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Health Desk articles

Can animals with no symptoms spread COVID?

Yes, but mostly to other animals of the same species. Currently, there is no evidence that animals are a major cause of spreading COVID-19 and the risk of animals passing COVID-19 to humans is low. According to a recently published study in the New England Journal of Medicine, transmission of the virus has been reported between cats, none of which had symptoms. The study found that three domestic cats infected with the SARS-CoV-2 virus that causes COVID-19 were able to transmit the virus to three other cats with no previous infection. None of the cats in the experiment showed any symptoms during the course of infection, but researchers found the continued spreading the virus from their noses for about six days. However, the research is rapidly evolving. This is just the first study to document asymptomatic transmission of COVID-19 in cats and as of now, there is no evidence of transmission of COVID-19 from cats to humans. Cats aren't the only animals that have been shown to spread the virus with no symptoms. Based on recent research conducted by the Dutch government, it is believed that minks infected with COVID-19 spread the virus to two human employees at regional farms. The minks were having symptoms of a respiratory illness, while another study about COVID-19 in animals has shown that mink can be infected with the virus without having any symptoms. Dogs, tigers, lions, and ferrets have also tested positive for COVID-19, but these animals all showed symptoms after testing positive for the virus and likely acquired the virus from humans.

What do we know about mouth and nose rinses, washes, sprays, or creams to prevent COVID-19?

There is no scientific evidence to support using home or traditional therapies to prevent COVID-19 at this time. The World Health Organization (WHO) and other international health leaders say that caution is needed when considering “traditional remedies” as preventative measures or treatments for COVID-19, because they have not been widely studied and may cause harm in some cases. There are many traditional remedies and home remedies that have been promoted to prevent COVID-19 infection. People have suggested using mouth or nasal washes, sprays, and creams (or fats) could prevent the virus from entering the body or kill the virus in the nasal cavity (nose) and throat before it has a chance to spread. **Nasal (nose) washes:** There is no scientific evidence that suggests rinsing the inside of your nose will prevent COVID-19 infection. Additionally, for patients with COVID-19, researchers have raised a concern about using contaminated nasal rinse bottles (as well as surfaces and rinse fluids), suggesting they could be a source of exposure. **Nasal (nose) sprays:** Ongoing studies seek to learn more about how saline, iodine, special soaps, and other ingredients used as nasal washes and sprays may help improve virus symptoms and decrease the spread of COVID-19.  One Israeli study published in November 2020, and recently re-released with updates as a pre-print in January 2021, shows promising results for a nasal spray known as Taffix. Taffix is a nasal inhaler approved for sale and used for the prevention of respiratory viral infections in Israel and some other countries. The 2020/2021 study analyzed 243 members of a Jewish ultra-orthodox synagogue community during a high holiday, in which individuals were gathered and praying throughout the day. At the two-week follow-up mark of the event, the study investigators found that the individuals who used Taffix had a reduction in odds of COVID-19 infection by 78%, compared to those who did not use Taffix. Eighteen members out of the total 243 were infected with COVID-19, 16 in the no-Taffix group and 2 in the Taffix group, both of whom did not adhere to the recommended use. Studies are ongoing to test over the counter and other types of nasal sprays for protection against COVID-19, with some showing early promise in lab and animal studies. **Mouthwash, rinses, and gargle solutions:** Like nasal washes and sprays, there is no scientific evidence that suggests using mouthwashes, rinses, and gargles will prevent COVID-19 infection. Ongoing studies seek to learn about how special antiseptic mouthwashes may help prevent COVID-19 (see the Experimental Therapies section below). So far, many studies have explored these treatments in laboratory cells, and data on humans is limited. **Alcohol, chlorine, or disinfectant spray:** Alcohol, chlorine (e.g. bleach solutions), or disinfectant sprays should never be sprayed or applied to your nose, mouth, or eyes, and doing so may cause serious harm. Drinking alcohol will not prevent or treat COVID-19. **Fats or oils:** This includes coconut oil, ghee, sesame oil, shea butter, petroleum jelly, and others. There is no scientific evidence that nasal treatments or mouth rinses with different fats will prevent, treat, or cure COVID-19. While many types of fats or oils (like coconut oil, sesame oil, and others) have been shown to kill or stop bad bacteria in cell-based laboratory studies, most of these studies have focused on how these ingredients may be used to prevent bacterial growth on food to improve food safety. Studies have not looked at the effect of fats on prevention of viral or bacterial infections in humans when applied in the nose or used as a mouth rinse. There is no scientific evidence that supports the theory that using these oils would improve health or prevent illness. In addition, though rare, it is possible that inhaling fats from the inside of the nose can cause lung problems. **Steam inhalation:** Though inhaling steam may help to thin mucous or relieve congestion (stuffy nose), there is no scientific evidence to suggest that inhaling steam will prevent or treat COVID-19. Contact with steaming hot water can cause burns, and inhaling steam can burn the inside of your nose. **Experimental therapies:** There are ongoing studies using nasal sprays (and rinses) and special mouthwashes to prevent COVID-19, such as the Taffix study discussed above. Much of the current scientific evidence is based on animal or laboratory cell studies. For humans, efficacy and safety studies are ongoing, and most treatments are not recommended for the public at this time. Currently, studies seek to understand if nasal rinses (using saltwater, special soaps, and other ingredients) may help to improve symptoms and decrease the viral load in patients with COVID-19 (with the thought that decreasing the viral load could decrease how much an infected person may spread the virus). Researchers are also studying whether gargling or rinsing with special solutions (e.g. povidone-iodine) may help prevent healthcare workers from contracting COVID-19. A pre-print study or a nasal spray medication (INNA-051) has shown good results in preventing COVID-19 in ferrets, but human studies have not yet begun. Human study results for Taffix nasal spray and its pre-existing approval for prevention of respiratory viral infections makes it feasible for human use in protection against COVID-19; however, it is not a replacement for mask use and physical distancing. To prevent COVID-19 infection, health authorities continue to recommend avoiding crowds, practicing social distancing measures (at least 6 feet/2 meters apart), frequent and careful handwashing, wearing face masks (wearing a cloth mask over a surgical mask is recommended by the U.S. Centers for Disease Control and Prevention), staying home when possible (especially if you are sick), clean high-touch surfaces often, and avoid touching your nose, eyes, and mouth.

What do we know about the Pfizer vaccine so far?

The Pfizer vaccine is being developed and produced by Pfizer, Inc. and the biotech company BioNTech SE. It is a genetic mRNA vaccine (mRNA-1273) currently in Phase 3 clinical trials across the globe. Here is a breakdown of everything you need to know so far about this vaccine’s development. \*\*Collaborators: \*\*Biopharmaceutical company Pfizer Inc, based in New York City, and BioNTech, biotechnology company based in Mainz, Germany, are collaborating on vaccine development and testing for the mRNA-based vaccine candidate BNT162b2. \*\*Latest information on how well the vaccine works:\*\* On November 30, 2020 with primary efficacy analysis data from its Phase 3 trial, Pfizer announced its experimental COVID-19 vaccine to be 95% effective 28 days after the first of two doses.  Out of approximately 44,000 total study participants, 170 contracted COVID-19. 162 who got infected were from the placebo group—meaning they didn’t receive the vaccine—and only 8 who got infected were in the group that was vaccinated with the Pfizer vaccine.  Ten of the COVID-19 cases were severe. Nine of those people were from the placebo group. One severe case was in the vaccinated group. This suggests the vaccine has high protection for severe COVID-19 cases, at 95% efficacy, meaning that if 100 study participants were the vaccine doses, 95 patients would not contract the disease and 5 would.  There have been no reported COVID-19-related deaths in the study. These new results of 95% efficacy are higher than the vaccine’s first interim analysis conducted during the study (announced on November 9th, 2020), which reported 90% efficacy based on an analysis of 94 COVID-19 cases among trial participants. Based on a study published in February 2021 in the New England Journal of Medicine, the Pfizer-BioNTech vaccine was found to appear to be highly effective against the more transmissible variant of the virus first detected in the U.K. (B.1.1.7) (virtually no drop from 95% efficacy). However, the vaccine showed a decreased ability to neutralize the strain first detected in South Africa (B.1.351). Specifically, they found that there was about a two-thirds drop in neutralization power (antibody power) against this variant compared to other forms of the SARS-CoV-2 coronavirus. It’s important to note that the vaccine was still able to neutralize the virus, and likely still may protect individuals from getting severe forms of the virus. In addition, these are initial lab experiments that are difficult to extrapolate results from. Pfizer has said that evidence is needed to understand how the vaccine works against the variant in real life. The company stated, "Nevertheless, Pfizer and BioNTech are taking the necessary steps, making the right investments, and engaging in the appropriate conversations with regulators to be in a position to develop and seek authorization for an updated mRNA vaccine or booster once a strain that significantly reduces the protection from the vaccine is identified.” \*\*Approvals:\*\* As of December 2, 2020, the U.K. authorized the distribution of Pfizer and BioNTech’s COVID-19 mRNA vaccine BNT162b2 for emergency supply, making the vaccine the first in the world to achieve authorization for COVID-19. Two days following the U.K.’s authorization, Bahrain approved the emergency use of the Pfizer and BioNTech vaccine, making it the second country in the world to do so. Five days following on December 9, Canada’s regulatory agency Health Canada approved the vaccine. On Friday, December 11, 2020, the U.S. Food and Drug Administration (FDA) authorized the Pfizer and BioNTech vaccine. Soon after, Pfizer and BioNTech bega rolling review processes with other global regulatory bodies, including in the U.S., Europe, Australia and Japan, and has been submitting applications to other regulatory agencies around the world, primarily in the Global North, with a range of approvals. \*\*Distribution timeline:\*\* Following the U.K.’s emergency approval on December 2, 2020, the companies began delivering the first doses to the U.K. nearly immediately, starting on December 8, 2020. Canada is set to receive 249,000 doses before the end of December to distribute across 14 different vaccination sites throughout Canadian cities. Following the U.S. approval of the vaccine on December 11, 2020, the U.S. will initially distribute approximately 2.9 million doses to all 50 states.  The distribution timeline for other countries undergoing the approval process will depend on the distribution decisions made by regulators there. Some countries are already coordinating pre-approval distribution and in many of these regions and countries, logistics surrounding the supply chain of the vaccine are being decided upon and run through so that when there is an approval, distribution can begin immediately. \*\*Distribution plan:\*\* In projections, Pfizer hopes to produce and supply up to 25 million vaccine doses in 2020 and 100 million doses before the start of March, with an estimated total distribution of up to 1.3 billion doses in 2021. Four of Pfizer’s facilities are part of the manufacturing and supply chain; St. Louis, MO; Andover, MA; and Kalamazoo, MI in the U.S.; and Puurs in Belgium. BioNTech’s German sites will also be leveraged for global supply. Each of these sites are important links in a global supply chain being assembled to tackle the massive logistical challenge of distributing COVID-19 vaccines around the world.  Jurisdictions primarily have the responsibility of determining who receives the vaccine in what order. For instance, within the U.S. each state will receive a certain number of doses of the vaccine based on residential populations. States have been asked to create their own plans for who will get the first doses.  In the U.K., British front-line health-care workers, as well as care-home staff and residents, are receiving the first doses. Bahrain has said that they plan to inoculate everyone 18 years and older at 27 different medical facilities, hoping to be able to vaccinate 10,000 people a day; so far, they have the second-highest vaccination rate in the world behind Israel. In general, the most likely distribution plan is for the vaccine to first go to emergency department clinicians, outpatient clinicians, testers at symptomatic sites, other high-risk health care workers, immunocompromised individuals, EMTs, and potentially essential federal employees, followed by the rest of the general population.  Vaccination distribution in some countries is moving more slowly than anticipated. In the U.S, for example, just 2.6 million individuals were vaccinated by December 31, 2020 compared to the 20 million goal by the end of 2020. In response, scientists and public health practitioners are considering vaccination tactics that differ from those that the FDA and other country’s health regulatory bodies approved. The tactics being considered are primarily halving doses of vaccines and delaying second doses to get first doses to more individuals, but also include reducing the number of doses and mixing and matching doses.  Health officials in the UK have already decided to delay second doses of two vaccines, one made by AstraZeneca and one made by Pfizer and BioNTech, and to mix and match the two vaccines for the two doses under limited circumstances. This decision has received mixed responses from scientists and public health practitioners, many of whom are concerned about the lack of data, particularly with regards to a mix-and-match approach.  The U.S. FDA critiqued the idea of halving the doses of the Moderna vaccine, saying that the idea was “premature and not rooted solidly in the available science.” Studies are underway to determine whether doses of the Moderna COVID-19 vaccine can be halved to 50 micrograms in order to double the supply of the vaccination doses in the U.S., according to the National Institutes of Health and Moderna.  \*\*Vaccine storage conditions:\*\* Storage requirements are important to consider for new vaccines. In order for vaccines to be safe and effective, they must be held at the correct temperature during distribution and storage in health centers, pharmacies, and clinics. Maintaining the correct storage temperature can be difficult, especially if the vaccine’s temperature requirement is very cold.  The Pfizer and BioNTech vaccine can be stored for five days at refrigerated 2-8°C (36-46°F) conditions (refrigerators that are commonly available at hospitals); up to 15 days in Pfizer thermal shippers in which doses will arrive that can be used as temporary storage units by refilling with dry ice; and up to 6 months in ultra-low-temperature freezers, which are commercially available and can extend the vaccine’s shelf life.  With regards to transit, Pfizer is using dry ice to maintain the recommended temperature conditions of -70°C±10°C (-94°F) for up to 10 days while in transit. However, Pfizer and BioNTech have determined that the vaccine can be moved only four times. \*\*Type of vaccine:\*\* The mRNA-1273 vaccine is what scientists are calling a genetic mRNA vaccine. This type of vaccine works by using genetic information from the coronavirus, which is injected into the body. The genetic information enters into human cells, instructs the body to make special spike proteins like the coronavirus, and causes the immune system to respond. \*\*Dosage:\*\* In the current Phase 3 clinical trial, participants receive two injections of 30 micrograms each into their upper arm muscle. The injections are given 21 days apart. Once an individual gets the first dose, they must get the second dose three weeks later in order to complete the vaccination. If approved, researchers expect that the same dosage and schedule will be prescribed to the public. A recent Israeli study that released results in February 2021 by the Lancet found that a single dose of the Pfizer vaccine was 85% effective against COVID-19 infection between two and four weeks after the first dose, and that the overall reduction in infections was 75%, including asymptomatic cases. Public health practitioners are enthusiastic about this finding of high efficacy after just one dose; However, the authors cautioned that the low numbers of COVID-19 cases in the study, and the fact that the study was conducted at one hospital, make it difficult to reach exact estimates and that these findings should be interpreted with caution. The study also does not determine the length of protection. Pfizer did not comment on the data, stating that “the vaccine’s real-world effectiveness in several locations worldwide, including Israel.”   Studies out of the U.K., which has been the quickest to inoculate its population, have also found that a single dose of the Pfizer vaccine could avert most COVID-19-related hospitalizations, though investigators stated it was too early to give precise estimates of the effect. \*\*How the vaccine is being studied:\*\* Vaccines are tested and studied in multiple phases (phased testing) to determine if they are safe and work to prevent illness. Before a vaccine is tested on humans, which is known as the preclinical phase, it is tested on laboratory cells or animals. Once it is approved for human research, there are three phases that take place before the vaccine can be considered for approval for public use. During the first stage (Phase I), the new vaccine is provided to small groups of people—the first time the vaccine is tested in humans to test safety (primarily) and efficacy of the vaccine.  The second stage (Phase II) involves testing the vaccine on people who have similar characteristics (such as age and physical health) to the target population, or the group for which the vaccine is intended. The goal of this stage is to identify the most effective doses and schedule for Phase III trials. The final stage (Phase III) provides the vaccine to thousands of people from the target population to see how safe and effective it is.  Once the vaccine has undergone Phase 3 testing, the manufacturer can apply for a license from regulatory authorities (like the FDA in the US) to make the vaccine available for public use. Once approved, the drugmaker will work with national governments and international health organizations to monitor vaccine recipients for potential side effects from the vaccine that were not seen in clinical trials (this is called surveillance). This phase also helps researchers understand how well a vaccine works over a longer time frame and how safe it is for the population. \*\*How Pfizer looked for COVID-19 cases in their trials:\*\* Researchers have standard definitions for routinely detecting COVID-19 cases for both symptomatic and asymptomatic individuals. For symptomatic individuals, there are three definitions considered for defining a COVID-19 case for the study. The first two are for regular cases, and the third is for severe cases.  The first definition is the presence of at least one COVID-19 symptom and a positive COVID-19 test (such as a PCR test) during, or within 4 days before or after, the symptomatic period, either at the central laboratory or at a local testing facility. The second definition is the same, but expands the definition to include four additional COVID-19 symptoms defined by the CDC (fatigue; headache, nasal congestion or runny nose, nausea). The third definition, which defines severe COVID-19 cases for the study, is a confirmed COVID-19 test per the above guidelines in addition to one of the following symptoms: clinical signs at rest indicative of severe systemic illness, respiratory failure, evidence of shock, significant acute renal, hepatic, or neurologic dysfunction, admission to an ICU, or death. The Pfizer research protocol states that for individuals who do not clinically present COVID-19 (that is, asymptomatic individuals), a serological test is used for defining a case, which measures the amount of antibodies or proteins present in the individual’s blood, and a positive case is defined as the presence of antibodies in an individual who had a prior negative test. By using these four definitions, researchers are able to detect COVID-19 cases in both symptomatic and asymptomatic individuals. However, the pharmaceutical company has stated that there are more data on the vaccine’s safety and efficacy for symptomatic cases, and that more data is needed to better understand the vaccine’s safety and efficacy for asymptomatic cases. \*\*Preclinical testing:\*\* Before testing could begin on humans, the trial vaccine was tested on primates at both 30 micrograms and 100 micrograms. On September 9, 2020, results were published demonstrating that the Pfizer vaccine had strong antiviral protection against the virus SARS-CoV-2. As a result, the Pfizer and BioNTech were permitted to advance the vaccine into human clinical trials by the FDA in the form of through the Investigational New Drug application (IND). \*\*Phase 1 trial:\*\* 45 healthy adults 18–55 and 65–85 years old were randomly assigned to either the placebo group or the vaccine group to receive 2 doses at 21-day intervals of placebo or either of 2 mRNA-based vaccines (BNT162b2 or BNT162b1, which was one of several RNA-based SARS-CoV-2 vaccines studied in parallel for selection to advance to a next trial). Participants received either 10, 20, or 30 microgram dose levels of BNT162b1, or BNT162b2 on a 2-dose schedule, 21 days apart. Both participants and observers working on the study were “blinded,” or not aware of which participants were receiving the active vaccines (and which ones) versus the treatment, in order to help prevent bias.  Both with 10 micrograms and 30 micrograms of vaccine BNT162b1, and t 7 days after a second dose of 30 micrograms of the BNT162b2 vaccine, “SARS-CoV-2–neutralizing antibodies” were elicited—special proteins that disable viruses in the body—in younger adults (18-55 years of age) and older adults (65-85 years of age). Younger participants had 3.8 times more antibodies than people who had recovered from the virus. In older adults (65-85 years of age) the vaccine candidate triggered antibodies at 1.6 times the volume of those who had recovered from the virus in the same age group. Vaccine BNT162b2, now known as the “Pfizer vaccine,” was associated with fewer reactions (such as fever and chills), and was therefore selected for Phase 2/3 trials.  In terms of safety and tolerability of vaccine BNT162b2, reactions were still reported. Study participants reported pain at the injection site, headache, fatigue, muscle pain, chills, joint pain, and fever. Most of these reactions and symptoms peaked by the day after vaccination and resolved by day 7.  \*\*Phase 2/3 trial: \*\*In an effort to speed up the trial, Phases 2 and 2 of the Pfizer vaccine were combined. This phase continued off of Phase 1 and also contained a placebo group as a control with patients randomly assigned into either the placebo group or vaccine group for vaccine BNT162b2. As with Phase 1, the observers and participants were also “blinded.” The first 360 participants enrolled made up the “Phase 2” portion, with 180 randomly assigned to receive the active vaccine and 180 to receive the placebo, stratified equally between 18 to 55 years and >55 to 85 years. Phase 3 enrolled 43,538 trial participants overall, half of whom were randomly assigned to receive the vaccine and half of whom were randomly assigned to receive the placebo. Out of 170 cases of COVID-19 among the study participants,162 cases of COVID-19 were observed in the placebo group versus 8 cases in the vaccine group, indicating 95% efficacy of the vaccine. No serious safety concerns were observed. Data collection is ongoing. \*\*Reported side effects and safety concerns:\*\* The study’s Data Monitoring Committee did not report any serious safety concerns related to the vaccine based on the trial data. Adverse events at or greater than 2% in frequency that were reported were fatigue at 3.8% and headache at 2.0%. Potential allergic reactions occurred in 0.63% of those who received the vaccine, compared with 0.51% of those who received the placebo.  On December 9, one day after the Pfizer and BioNTech vaccine began being distributed to individuals outside of the clinical trial in the UK, UK regulators advised that individuals with a history of anaphylaxis to a vaccine, medication, or food should not receive the vaccine. This warning was issued in response to two reports of anaphylaxis (severe allergic reaction) -- both among individuals with histories of severe allergies -- and one report of a possible allergic reaction since distribution in the UK began. Pfizer and BioNTech have stated that they are working with investigators to better understand the cases and causes of the reactions.  Within the clinical trial, individuals with a history of severe allergic reactions were excluded from the trials, and doctors were asked to look for such reactions in trial participants who weren’t previously known to have severe allergies. UK regulators also required health care workers to report any negative reactions to help regulators collect more information about safety and effectiveness.  In addition, four people who received the vaccine during trials later developed Bell’s palsy at 3, 9, 37, and 48 days after vaccination, respectively. Because these trials were so large, however, this is not more than we would expect to develop Bell’s palsy in a group of this size by chance. Bell’s palsy is a weakness or paralysis of one side of the face which is usually temporary. Any cases of Bell’s palsy and any other potential side effects or adverse reactions will continue to be monitored and evaluated for as the vaccine continues to be rolled out to the public. \*\*Impact on different populations:\*\* Pfizer and BioNTech both say they aimed to make their trials as diverse as possible to understand the vaccine’s effect on different populations. The trial participants are approximately 30% U.S. participants and 42% non-U.S. participants from across 150 trial sites globally. The participants are reported to have racially and ethnically diverse backgrounds. In the trials, 41% of global and 45% of U.S. participants are 56-85 years of age. Efficacy was reported to be consistent across age, gender, race and ethnicity demographics.  Notably, the observed efficacy in individuals over 65 years of age was observed to be greater than 94%. In September 2020, Pfizer and BioNTech expanded Phase 3 enrollment to approximately 44,000 participants. This expansion allowed for the enrollment of new, more diverse, populations, including adolescents as young as 16 years of age, and individuals with chronic, stable human immunodeficiency viruses (HIV), Hepatitis C, or Hepatitis B infection. In October 2020, Pfizer and BioNTech received permission from the FDA to enroll adolescents as young as 12. Their explanation for these expansions is to enable better understanding of the potential safety and efficacy of the vaccine in individuals from more ages and backgrounds.

What is the context behind the misinformation about fetal cells used in the AstraZeneca COVID-19 vaccine?

The Oxford-AstraZeneca COVID-19 vaccine (AZD1222) does not contain human cells or tissues. The AZD122 (ChAdOx1 nCov-19) is a weakened version of an adenovirus—a harmless virus that usually causes the common cold in chimpanzees— and is used as a way to transport the vaccine's ingredients into the human body. This type of vaccine is called a "vector vaccine," because the adenovirus serves as the vector (or vehicle) for getting the drug into human cells. The adenovirus can stimulate a response from a person's immune system when their body detects it in cells. Essentially, the vaccine helps train human bodies to detect and eliminate a real COVID-19 infection through showing it mock spike proteins, before COVID-19 can cause any severe symptoms or a severe infection. During preclinical research, MRC-5 cells were used to determine how effective the vaccine may be in human clinical trials, but the MRC-5 cells are not used in the manufacturing process for this vaccine. There are different processes used to make vaccines. Often, when vaccines are being made, viruses are propagated (grown in the lab) in special laboratory cells, and the viruses are then collected to make the vaccine. To make this COVID-19 vaccine, the virus is propagated using another type of cells, the HEK 293 cell line. However, there is no evidence that these cells are present in the vaccine itself. The cells are removed through a filtering and purification process that breaks down the cellular pieces and remaining DNA before a vaccine is deployed to humans. The HEK 293 cells and MRC-5 cells (mentioned above), as well as many other research cell lines, were collected from fetal tissue in the 1960s and 1970s. Since then, labs have reproduced those cell lines for some medical purposes, including research and vaccine development. These cells are not part of the vaccine. It is also important to distinguish between fetal cells and cultured (lab grown) cells. Fetal cells are not used in vaccine production.

What do we know about the ingredients used in the Pfizer-BioNTech and Moderna COVID-19 vaccines?

Like other vaccines, COVID-19 vaccines contain an active ingredient that aims to teach the body how to recognize the virus, so that the defend itself when exposed. There are multiple ingredients in vaccines in addition to the active ingredient. The Pfizer-BioNTech and Moderna COVID-19 vaccines both use mRNA as the active ingredient and also contain ingredients like potassium chloride, monobasic potassium, phosphate, sodium chloride, dibasic sodium phosphate, and sucrose. Potassium, chloride, and phosphate are minerals that are commonly found in foods and medications. Sodium chloride is another name for salt, and sucrose is a type of sugar. All of these ingredients are commonly used in vaccines to deliver the medication as a liquid solution, and to maintain stability and pH levels. Unlike other vaccines, mRNA vaccines use very small fats (lipid nanoparticles) to deliver the mRNA into your body. Once in the body, these fats protect the mRNA, so that the mRNA can make it to cells, where it helps the body develop immunity. Once the mRNA is delivered to the cells, the lipids dissolve and are removed from the body. One part of the lipid nanoparticle is something called polyethylene glycol (PEG), an ingredient used in many toothpastes, shampoos, and other products as a thickener, moisture carrier, and solvent. PEG is also used in medications, including as laxatives, and in biopharmaceutical products. PEG has occasionally resulted in severe allergic reactions in some people. PEG has not been used in an approved vaccine before. Some scientists have suggested that PEG could be the reason for the allergy-like reactions that a small number of people have had following COVID-19 vaccination. However, this speculation has not been confirmed, and there remains considerable debate about whether or not PEG may have caused these reactions. The US National Institute of Allergy and Infectious Diseases is currently working with the US Food and Drug Administration to study how people respond to the mRNA vaccines when they have a history of allergic reactions or have high levels of antibodies against PEG. Severe reactions to vaccines can happen, but reactions to the mRNA COVID-19 vaccines have been rare (as of February 2021). In general, vaccination is both recommended and safe for most people.

What do we know about claims that masks do not work?

Despite ongoing claims that masks do not work, research shows that masks do work to help prevent transmission of respiratory diseases like COVID-19 and influenza (flu). A recent lab study conducted by the U.S. Centers for Disease Control and Prevention found that by wearing two masks, people's protection against virus in the air (also called aerosolized particles) was dramatically increased. The study demonstrated that wearing any kind of mask provides significantly more protection against infectious aerosols than not wearing a mask. Additionally, when dummies who wore two masks - like cloth face masks over surgical masks - were exposed to infectious aerosols, their level of protection was roughly 92%. (The group now recommends fitting a cloth mask over a medical procedure mask, and knotting the ear loops of a medical procedure mask and then tucking in and flattening the extra material close to the face. However, the U.S. CDC does not recommend wearing two disposable masks at one time or another mask on top of a KN95 or N95 mask.) Research before the COVID-19 pandemic had already shown the effectiveness of masks in healthcare settings, in homes of infected people, as well as in public settings during previous outbreaks of diseases like severe acute respiratory syndrome (SARS). Research during the COVID-19 pandemic has provided more evidence that masks are effective for reducing community transmission and saving lives. Many governments that responded effectively to the COVID-19 pandemic and lost fewer lives as a result, such as Taiwan, have used policies that include wearing masks in public settings. Beyond health research on the benefits of wearing masks for reducing transmission and saving lives, economic research has also shown links between wearing masks and improved long-term business/economic outcomes. For example, research by Goldman Sachs suggests that adopting a national mask mandate requiring the public to wear masks in the U.S. could potentially reduce the need for renewed lockdowns that "would otherwise subtract nearly 5% from GDP (Gross Domestic Product)." As there are many different types of masks in the market, it is important to remember that masks can differ in effectiveness. For example, now that healthcare workers have a better supply of personal protective equipment (PPE) such as medical-grade N95 respirators and surgical masks, some public health professionals are now calling for the general public to also wear more effective medical-grade masks. Previous recommendations focused on fabric face coverings for the general public, in order to ensure supply of medical-grade masks for healthcare workers. Now that the supply chain has improved in response to the COVID-19 pandemic, community transmission may be reduced further by encouraging the public to switch to more effective medical-grade masks when possible. Some European countries have moved to require medical-grade masks in public settings. Similarly, some public health professionals suggest that the public can increase the effectiveness of fabric face coverings by wearing multiple layers to filter out more respiratory particles. Dr. Anthony Fauci, a leading doctor and scientist for the U.S. COVID-19 response, has encouraged doubling up masks to increase the protection offered by porous fabric face coverings. In summary, masks do work and this is supported by research, although different types of masks vary in their effectiveness and masks alone are insufficient to respond to the COVID-19 pandemic (other public health measures, like maintaining physical distance and hygiene, are also needed). Experts suggest now focusing on how to make wearing masks in public even more effective.

What is the existing research on copper's effectiveness in dealing with COVID-19, particularly when used in face masks?

There has been research suggesting that SARS-CoV-2, the virus that causes the disease COVID-19, does not survive long on copper surfaces. However, this does not mean that copper products are always effective in protecting against COVID-19. In fact, many copper-based products currently on the market do not contain a sufficient concentration of copper for significant antimicrobial effects. One study that is commonly used as evidence on the effectiveness of copper is an April 2020 publication in the New England Journal of Medicine, which found that “no viable SARS-CoV-2 was measured after 4 hours” on copper surfaces. It is important to remember that this study in a controlled laboratory setting does not mean all commercial products with copper are able to protect against COVID-19 in real life. Products containing copper can vary widely and many products have not been designed, manufactured, and tested properly to ensure effectiveness. Furthermore, copper does not act instantaneously against microbes such as viruses, with research findings showing that copper can take 45 minutes just to reduce the amount of virus on a surface by half.  Dr. Lindsay Marr, an aerosol scientist from Virginia Polytechnic Institute and State University (Virginia Tech), suggested in a New York Times article that copper-based face coverings could potentially “come in handy for people who mishandle their mask,” assuming that “a hefty dose of copper could diminish the chances of viable virus making it into the eyes, nose or mouth via a wayward hand that’s touched the front of a mask.” Unfortunately, if a copper face covering does not contain sufficient copper, the product “won’t confer any more benefit than just regular masks” according to Dr. Karrera Djoko, a biochemist and microbiologist from Durham University. Additionally, Dr. Djoko also warns that there could be issues with durability of copper products, particularly for face masks that may be repeatedly disinfected, because many common household cleaners have compounds that can strip copper ions from a surface.  There can be some promising uses of copper to protect against COVID-19, such as using copper surfaces in healthcare settings to help reduce risk of hospital-acquired infections. That said, health experts warn against relying on commercially sold products with copper, such as copper face coverings, which are not carefully regulated and have not been rigorously tested for effectiveness.

What do we know so far about the new virus mutation in South England?

A recent surge of coronavirus cases in London and surrounding areas of Southeast England is thought to be linked to a new, fast-spreading variant of the COVID-19 virus. The new variant was detected in samples taken in late September in the Southeast English county of Kent, and now accounts for approximately 60% of COVID-19 cases in London. Aptly named “Variant Under Investigation,” or VUI-202012/01 for short, there are insufficient data and too many unknowns at this time to draw any conclusions about the new variant, according to the UK government’s New and Emerging Respiratory Threat Advisory Group (NERVTAG) and Science Magazine. Until scientists and public health officials run rigorous laboratory experiments and checks, they cannot provide definitive answers about the new variant. They stress the importance of care providers, public health practitioners, researchers, and policymakers keeping a vigilant eye on the new strain to learn more about its behavior and potential impacts on disease burden and spread.  Importantly, media channels report that there is no indication that the Pfizer-BioNTech and Moderna coronavirus vaccines will be less effective in protecting people from contracting this mutation of the virus. Additionally, there is no definitive evidence to suggest that the new variant is more deadly or linked to more severe illness. All viruses mutate and in the case of COVID-19, researchers have observed thousands of tiny modifications of since March 2020. However, the new variant of COVID-19 raises alarm for three primary reasons:  1 ) Early evidence indicates with “moderate confidence” that the new variant is significantly more transmissible than previous versions. One study from Imperial College London suggests that it is up to 70% more transmissible. Another way scientists measure virus transmission at a population level is by looking at the virus’ R0, or “R naught”, which describes the number of people one person can infect. A higher R naught is an indicator of pandemic growth, though actual growth depends on public health actions taken by the public. In recent weeks, the R naught in the region with the mutation is thought to have increased by 0.4 with the emergence of the new variant. From early laboratory experiments, scientists studying the new coronavirus variant have identified up to 23 changes to its genetic makeup, according to multiple sources. It is unprecedented to see the coronavirus seemingly acquire more than a dozen mutations at once, according to Science Magazine. One of these mutations demonstrated improved ability to infect human cells. This change is linked to the rapidly growing number of infections in Southeast England that, unabated, may only continue to rise. 2 ) Many of the mutations altered an important part of the virus called the spike protein, a crown-like structure encasing the viral genetic material and giving the virus its name. One such change alters a key piece of the spike protein, known as the “receptor-binding domain,” that binds to and unlocks the entryway into human cells. The new variant’s uncanny skill at entering and infecting cells likely gives it a leg up over other strains. This novel behavior may in part explain why the new variant has been detected in the majority of new cases in London, ousting other strains that may be less skilled in this mechanism.  3 ) The fact that the new variant has begun to rapidly replace other versions of COVID-19 as seen across testing centers in parts of England puts scientists on high alert. Virus mutations have the potential to introduce new and possibly aggressive behaviors, as well as increased transmission. For this reason, it is critical that scientists keep a close watch. These early research findings together suggest that the new variant is highly contagious, more so than previous strains. Its rapid dominance remains particularly concerning especially as it may take months to accurately capture how the new variant will take hold. However, it’s also important to not panic before we have more data and a more complete picture of this variant and its implications.

With healthcare workers getting many of the first vaccine distributions, how can vaccinations be coordinated for off-site emergency medical services (EMS) personnel?

The prioritization of initial COVID-19 vaccinations varies widely from location to location, with decisions being made at the federal, state, county and facility level. Emergency medical services (EMS) personnel are often included among the groups receiving the highest priority for the first shipments of the COVID-19 vaccine. Since the initial supply is not sufficient to vaccinate everyone within the highest priority groups, however, difficult decisions are being made about who is to receive the COVID-19 vaccines first. Some places are choosing to include EMS personnel outside of hospitals, such as in the fire department, in the first wave of COVID-19 vaccinations. Other places are distributing their first shipments of the COVID-19 vaccine straight to hospitals first. Decision-makers for each location can set priorities by taking into account public health guidance as well as data about their specific context regarding what resources are available and what are the most urgent needs.  Several public health frameworks exist and have informed decision-makers, including the U.S. Centers for Disease Control and Prevention (CDC), as they set their vaccination priorities for COVID-19.  In John Hopkins University’s framework for COVID-19 vaccine priority groups, Tier 1 includes front-line EMS personnel and Tier 2 includes other essential workers such as personnel in fire and police departments. In the National Academies of Medicine preliminary framework for equitable allocation of the COVID-19 vaccine, Phase 1a’s earliest “jumpstart phase” includes first responders like EMS, police and fire personnel. Depending on which public health frameworks are used, there can be differences in the recommendations for when to include EMS personnel outside of a hospital, such as in a fire department.  Additionally, the U.S. CDC previously made suggestions for sub-categorization of Tier 1 vaccine distribution when there is an “extremely short supply” during a pandemic of other diseases, such as influenza. The proposed ranking of groups within Tier 1 in this situation is: 1. Front-line inpatient and hospital-based health care personnel caring for sickest persons; health care personnel with highest risk of exposure 2. Deployed and mission critical personnel who play essential role in national security 3. Front-line EMS 4. Front-line outpatient health care personnel, pharmacists and pharmacy technicians, and public health personnel who provide immunizations and outpatient care 5. Front-line law enforcement and fire services personnel 6. Pregnant women and infants aged 6 -11 months old 7. Remaining groups within Tier 1, including but not limited to: inpatient and outpatient healthcare personnel not vaccinated previously; public health personnel; other EMS, law enforcement, and fire services personnel; manufacturers of pandemic vaccine and antiviral drugs While this guidance can be a point of reference for some locations seeking to decide how to allocate vaccinations to EMS personnel outside of hospital settings (who in this case might be categorized in group 3 or 7, depending on their involvement in front-line care), there are some notable differences that should be taken into account for COVID-19, compared to influenza. For example, COVID-19 has been especially deadly for older adults in long-term care settings, which is why long-term care residents and personnel are among the top tier priorities for COVID-19 vaccinations according to U.S. federal recommendations.  While the specific prioritization of EMS personnel outside of hospital settings may vary depending on the location, it is important for decision-makers to have a plan for how to vaccinate non-hospital-based EMS personnel and communicate this plan with transparency.

What do we know so far about how the U.K. is approving and rolling out vaccines?

**Approval status:** On December 2, 2020, the U.K. Medicines and Healthcare products Regulatory Agency (MHRA) granted an emergency-use authorization to a 2-dose mRNA vaccine developed by Pfizer and BioNTech, roughly seven months after the clinical trials started. Other vaccine candidates are currently under review by the regulator. **Approval processes:** In the United Kingdom, vaccines are approved by the regulator (the MHRA) based on criteria including safety, quality, and efficacy. The MHRA has been using a "rolling review" process since June 2020 to assess COVID-19 vaccines in an accelerated timeframe, with teams of scientists often requesting and reviewing data on various topics in parallel. The European Union (EU) requires vaccines to be authorized by the European Medicines Agency (EMA), but allows individual countries to use an emergency procedure to distribute a vaccine for temporary use in their domestic market. The MHRA chief executive stated that they used this existing EU provision to fast-track approval in the U.K. before the rest of the EU, since the U.K. is still subject to EU rules until their transition period for leaving is completed on December 31, 2020. **Distribution status:** The U.K. announced that 357 million doses of seven different vaccines have been purchased, which includes 40 million doses of the Pfizer and BioNTech vaccine. An initial delivery of 800,000 doses of the Pfizer and BioNTech vaccine (which can provide two doses to 400,000 people) was received from a manufacturing site in Belgium, and was divided between the four countries of the U.K. on the basis of population (with most going to England and Wales, 65,500 doses going to Scotland, and 25,000 doses going to Northern Ireland). The first vaccinations outside of trials in the U.K. began on December 8, 2020, prioritizing residents and caretakers in care homes for older adults (also known as aged-care). A 90-year-old woman was the first person outside of trials to receive a vaccine dose in her country. **Distribution priorities:** The U.K. Joint Committee on Vaccination and Immunisation (JCVI) identified that the first phase of vaccinations should focus on directly preventing mortality and supporting the National Health Service (NHS) as well as the social care system. This first phase includes nine priority groups, which taken together are estimated to represent 99% of preventable mortality: 1. Residents in a care home for older adults and their carers 2. All those 80 years of age and over and frontline health and social care workers 3. All those 75 years of age and over 4. All those 70 years of age and over and clinically extremely vulnerable individuals 5. All those 65 years of age and over 6. All individuals aged 16 years to 64 years with underlying health conditions which put them at higher risk of serious disease and mortality 7. All those 60 years of age and over 8. All those 55 years of age and over 9. All those 50 years of age and over The next phase of vaccinations will focus on further reducing hospitalization and targeting those at high risk of exposure and/or those delivering key public services. This next phase is likely to include people at increased risk of exposure to COVID-19 due to their occupation, such as first responders, the military, those involved in the justice system, teachers, transport workers, and public servants essential to the pandemic response. **Distribution processes:** The Pfizer and BioNTech vaccine requires storage in ultra-cold temperatures of -70 degrees Celsius. A shipping box has been developed that is packed with dry ice to maintain the necessary temperature for 5,000 doses, which can be transported by airplane. Once the doses arrive in the target country, the country can store the dry ice packs in a freezer farm for up to 6 months. If unopened, the dry ice packs can keep the doses cold for up to 10 days during transport. After the vaccine is thawed, it can be stored for up to 5 days at between 2 and 8 degrees Celsius. The U.K. Security Service (MI5) and National Cyber Security Centre (NCSC) are working to provide security for the vaccine supply chain and distribution, which could be disrupted by hacking and other attacks. The U.K. Ministry of Defence has announced that it is providing 60 military planners to work with the government's vaccine task force and 56 personnel to help construct vaccination centers. The U.K. Armed Forces Minister announced that more than 2,000 military personnel have been deployed so far to help with testing and other COVID-19 response, and that 13,500 military personnel remain on "high readiness" to provide support. In England, 50 NHS hospitals are serving as initial hubs for administering the vaccine.

What do rising COVID-19 cases during the fall of 2020 in U.S. Midwestern states mean for other states, like Florida?

Without a distinct, explicit, and obvious uptick in travel pattern volumes, and access to data about those travel pattern volumes, it is not possible to predict how the number of cases in one state or geographical region, such as the U.S. Midwest, will impact COVID-19 infection rates in another state or region, such as Florida. Known mass migration from one region to another could help epidemiologists predict how COVID-19 may spread, but U.S. travel tends to be spontaneous and multidirectional, with individuals traveling across and between different regions, rather than traveling as a large group from one specific region to another. Though widespread travel and transmission patterns are difficult to predict, we can reasonably conclude that a high volume of COVID-19 cases throughout the United States means that the likelihood of transmission of COVID-19 in the country is high, compared to other parts of the world. To prevent the spread of COVID-19, public health experts continue to recommend that people wash their hands, wear masks (the U.S. Centers for Disease Control and Prevention recommends wearing a cloth mask over a surgical mask for increased protection), avoid crowds (especially indoors), practice social distancing, and stay home when possible. Out of the top five states that have seen COVID-19 cases rise the fastest during the first couple weeks of October 2020, four states (Idaho, Nebraska, South Dakota, North Dakota) are in the Midwest. Some health care workers and public health researchers have referred to the rising cases in the Midwest during the fall of 2020 as a "third wave," after the summer wave and the initial wave of COVID-19 cases. Dr. Anthony Fauci and other infectious disease experts have warned that states across the U.S. could see another wave of COVID-19 cases, particularly with current case numbers remaining high in several places, colder weather setting in and coinciding with what is typically the annual influenza (flu) season, and people starting to become fatigued with maintaining pandemic prevention measures. Simultaneously in Florida, 5,558 new COVID-19 cases were reported on October 22, 2020, which is one of the highest single-day increases that the state has seen since mid-August 2020 (the only days with higher numbers in the fall of 2020 are thought to be due to irregularities in reporting). The reported increase brings Florida's statewide total to 768,091 COVID-19 cases and over 16,470 deaths related to COVID-19 as of October 22, 2020. Following the Florida Governor's decision on September 25, 2020 to move to Phase 3 of their reopening plans, including fully open bars and restaurants, public health experts have been warning that Florida could see a rise in COVID-19 cases and that this could also coincide with the anticipated flu season.

What would successful contact tracing look like following the President of the United States’ COVID-19 infection?

Given that the the period between exposure to COVID-19 and symptom onset can be between 2-14 days, U.S. President Donald Trump could have been infected as early as two weeks ago. He could have been contagious as early as approximately 12 days before his positive test result. Since other prominent individuals in Donald Trump’s circles have also tested positive in days following Trump’s positive result — such as Melania Trump, presidential adviser Hope Hicks, and Trump campaign manager Bill Stepien — all infected members of the White House may have overlapping chains of transmission and as a result, contact tracing efforts will be complex. As a result, the optimal, comprehensive contact tracing approach in this situation would look as follows:  1. Donald Trump and all individuals who tested positive in his close circles would provide detailed information on where they were and who they had close contact with in the 14 days prior each of their positive test results. Close contact includes anyone who has been within 6 feet (2 m) of any of them for at least 15 minutes, or indoors with any of them without a mask on within two days of any of the three diagnoses 2. A team of contact tracers would then quickly alert the identified individuals, to let them know that they may have been exposed to COVID-19 3. The individuals from the close contact group would then be assessed for symptoms and tested for COVID-19 4. The people from the close contact group who test negative for COVID-19 would then be instructed to self-quarantine for 14 days after they were exposed, keep social distance from others, self-monitor for COVID-19 symptoms, and send doctors and the state health department daily health updates 5. The people from the close contact group who don’t have symptoms, but have also not been tested, would be instructed to follow guidelines as if they tested negative 6. The people from the close contact group who test positive would be instructed to self-isolated and recover at home for minimum 10 days and then self-quarantine for 14 days after being exposed, seek medical care if they experience emergency warning signs, and monitor symptoms and avoid spreading the virus 7. The people from the list who have symptoms of COVID-19 but can’t be tested would be asked to follow the guidelines as if they tested positive 8. Each close contact would get tested again one week after initial testing 9. Contact tracing steps 1-8 would repeat for the close contacts of each individual who tests positive Though the incubation period of the virus that causes COVID-19 is 2-14 days, the incubation period of infection is most often 3-5 days, so it's most likely that Trump was infected between Saturday, 9/26/2020, and Monday, 9/28/2020. That makes him mostly likely infectious as of Tuesday, 9/29/2020. This entry was updated with new information on October 4, 2020.

In scientific terms, is it absolutely safe to say that "bald men are more likely to have COVID-19?"

No, it is not safe to say in scientific terms that bald men are more likely to have COVID-19. In May 2020, a research study was widely reported in news headlines, which suggested male pattern baldness (androgenetic alopecia) could mean higher risks for severe COVID-19 symptoms. However, this is not exactly what the researchers found. The authors of this publication also acknowledged there were research limitations meaning their results cannot be generalized to a larger population and further studies are needed. Published in the Journal of the American Academy of Dermatology (JAAD), the researchers wrote that out of 122 men and 53 women admitted with COVID-19 to hospitals in Madrid, Spain, they found 79% of the male patients had some hair loss or baldness (alopecia) while estimating the prevalence of baldness in the general population is only 31%-53%. However, the researchers acknowledged limitations of their findings, including how only 175 people were studied (in research terminology, this is considered a** **small sample size that limits how findings can be generalized to a larger population). They also acknowledged that patients in the study were all admitted to a hospital with COVID-19, meaning there was no comparison group (control group) of participants without COVID-19 to compare the findings against the general population. Additionally, the research did not include information about patient outcomes (such as how the patients fared after they were admitted to the hospital), so it was not possible for researchers to compare outcomes for patients with and without baldness. In general, many researchers and doctors have cautioned that older people and men are more likely to have severe cases of COVID-19 requiring hospitalization, and older men are also more likely to be bald. For these reasons, "bald men are more likely to have COVID-19" is an incorrect interpretation of the published research.

Is there a specific process through which COVID-19 enters the body? Does COVID-19 first enter through the throat before it "destroys" the lungs?

COVID-19 enters the body through the nose, mouth, and eyes. This happens primarily when someone infected with the virus releases small droplets of liquid that contain part of the virus through actions like coughing, sneezing, speaking, or singing. These small bits of virus range in size, from the wet, teardrop-sized types of droplets you might see when you sneeze, to microscopic ones that are so light and dry, they might remain in the air for hours. When a person is in close contact with these droplets, the virus enters the body through these three areas. Then, the virus lands at the back of the throat, also called the top of the upper respiratory tract, in roughly 80% of people who have mild cases of infection. For other more severe cases, the virus can then move down to the lungs, potentially causing pneumonia, which happens in 15-20% of cases, although most recover. When COVID-19 spreads to the lungs, it does not mean that they will be "destroyed." It means that there is an infection involving fluid within tiny branches of air tubes or sacs in the lungs called 'alveoli.' These air sacs may fill up with so much liquid or pus that they become swollen, and their walls can thicken, so it is hard for oxygen to be processed and delivered through the lungs, making it harder to breathe. Every virus has a different way of infecting humans, though many viruses gain entry into the body through the nose, mouth, and eyes and often cause upper respiratory infections like COVID-19.

In what way could the public better understand efficacy rates of COVID-19 vaccines published by various companies, and do the efficacy rates affect a population’s herd immunity if that is the ideal goal of vaccination programs?

Vaccine efficacy and vaccine effectiveness may sound similar, but are actually different terms to scientists and health professionals. According to the U.S. Centers for Disease Control and Prevention (U.S. CDC), vaccine efficacy is a term used to describe how well the vaccine protects clinical trial participants from getting sick or getting very sick. Vaccine efficacy refers to results reported from clinical trials and reflects circumstances specific to the research settings, rather than describing how well a vaccine works on the general public in real-world conditions.  So far many of the vaccine efficacy rates that have been released (ex. Moderna and Pfizer/BioNTech’s vaccine efficacy rates of ~95%) refer to how COVID-19 vaccine candidates can prevent symptomatic disease in people, not how the vaccine candidates reduce transmission. Researchers are still studying how effective the COVID-19 vaccines are in reducing transmission. “Herd immunity” refers to a given percentage of people that need to become immunized to a virus, through vaccines or through becoming infected naturally, against a virus in order to provide safety for an entire population - i.e. the herd. It’s the idea that if most people have developed immunity, then the rate of transmission will be low or non-existent. Researchers are still learning about what herd immunity for COVID-19 looks like. It is hypothesized that we may need at least 60-70% of the population vaccinated or recovered from infection in order to achieve herd immunity, but this has not yet been confirmed in real-world settings. Furthermore, the COVID-19 vaccine efficacy rates published by pharmaceutical companies do not yet tell us the exact vaccine effectiveness rates that can be expected in actual populations, and focus on how the vaccines prevent disease symptoms rather than how the vaccines reduce transmission. Researchers are still understanding how vaccine efficacy reported from clinical trials will impact herd immunity. It is currently thought that the percentage of people who agree to get vaccinated will be a more important factor for achieving herd immunity. It is important to remember that the goal of vaccination is not only to achieve herd immunity and reduce community transmission, in order to reduce the pressures on the healthcare system and protect at-risk individuals who may not be able to receive the vaccine for health reasons - vaccinations are also intended to protect individuals from getting sick or dying. Vaccinations play an important role for individual health as well as for public health on a societal level. Everyone who is able to get a vaccine is highly encouraged to do so, to help protect themselves as well as others.

Can gasoline and/or diesel be used to disinfect masks, surfaces, or even skin? What are potential dangers, if any, in doing so?

No. Gasoline and/or diesel should not be used as a disinfectant, does not work as a disinfectant, has not been shown to kill the virus that causes COVID-19, and may be very harmful to human health. According to the U.S. National Institute for Occupational Safety and Health, gasoline exposure through the skin or eyes, drinking, or breathing can cause many health problems including the following: ·      Irritation or burns of the eyes, skin, or mucous membranes (i.e. the tissues in the nose, eyes, mouth, throat) ·      Headache, weakness, blurred vision, dizziness, slurred speech, confusion, convulsions ·      Chemical pneumonitis (when liquid gasoline is inhaled into the lungs and causes damage) ·      Possible liver or kidney damage ·      Long-term exposure may cause cancer ·      Gasoline is flammable and improper storage / use can lead to fires and burn injuries Gasoline exposure should be avoided and, if accidental exposure does happen, washing the exposed area is important. When exposed to gas fumes, it is important to leave the area where the fumes are to an area with fresh air or ventilation. Seek medical help for breathing problems as well as slurred speech, dizziness, confusion, or other symptoms of neurological (brain and nervous system) problems. 

Is there a cure for COVID-19? What is the cure?

There is no known cure for COVID-19 right now, but there are ways to manage the symptoms of the disease. A cure is a substance or act that ends and relieves the symptoms of a medical condition so patients can have their health restored. One for COVID-19 is currently being researched in many clinical trials around the world, but no treatment or practice has been shown to effectively meet these standards. Healthcare professionals around the world are researching various treatments for COVID-19, including drugs that already exist to treat other conditions to see if they may be effective against COVID-19 as well. No treatments are currently approved by the U.S. Food and Drug Administration (FDA) for COVID-19, but because COVID-19 is a public health crisis, doctors can treat patients using some drugs that are not technically approved for COVID-19. Emergency use authorization enables unapproved medical products or unapproved uses of approved medical products to be used for diagnosis, treatment or prevention in an emergency setting, even if the treatments may still be under further study. Remdesivir, an antiviral drug manufactured by Gilead Sciences that stops the virus from replicating, received emergency use authorization by the U.S. FDA. It reportedly reduced the recovery time for hospitalized patients from 15 days to 11 days, and early results indicate that it may reduce mortality among patients who are very sick from COVID-19. In terms of clinical management of symptoms, the U.S. National Institutes of Health (NIH) COVID-19 treatment guidelines indicate that Remdesivir supplies are limited and should be prioritized for patients who need it most (hospitalized patients who require supplemental oxygen). The guidelines also recommend the use of dexamethasone, a steroid that can reduce inflammation, for patients who require ventilators or supplemental oxygen (and potentially other corticosteroids). Healthcare professionals may use ventilators and supplemental oxygen to ensure that hospitalized patients have a healthy supply of oxygen in the body, and monitor patients accordingly. Prone positioning (flipping COVID-19 patients onto their bellies in order to open up their lungs ) is also widely used to help patients recover from the virus. At present, there is no cure for COVID-19.

What must regulating bodies, such as the Food and Drug Administration (FDA), look out for when approving a vaccine for Emergency Use Authorization (EUA) vs. approving a vaccine for general use?

Regulatory agencies in multiple countries began granting approvals for emergency use of COVID-19 vaccine candidates in late 2020. The standards can vary from place to place but are typically rigorous, with a focus on evidence for safety and efficacy from large-scale clinical trials. Notable exceptions include China and Russia, which provided early approvals of vaccine candidates before large-scale clinical trials were completed and began widespread vaccinations of people outside of trials months earlier than most other countries. The process for emergency use authorizations can vary widely. For example, some regulatory agencies need to consider not only their country’s policies, but also regional agreements between countries like in the European Union. A few regulatory agencies, such as the U.S. FDA, also do their own careful analysis of the raw data, as opposed to relying on the findings provided from the vaccine manufacturers like the U.K. regulatory agency.  Several health experts have now raised the importance of approving the COVID-19 vaccines for general use, not just emergency use. A major concern is that COVID-19 vaccines may still be needed after the emergency nature of the current pandemic has finally subsided, in order to continue to protect people against COVID-19 in the future. As regulatory licensing for general use can take time and require even higher standards of evidence (ex. often the completion of phase 3 clinical trials), experts are urging regulatory agencies to continue these processes in order to be prepared for health needs after the pandemic. Otherwise, there is a risk of a gap in being able to vaccinate people against COVID-19 once the immediate emergency is over, if only emergency use authorizations have been granted.

Is indoor dining safe now, especially in covered tents?

Indoor dining is still high risk when it comes to dining during the COVID-19 pandemic, even if the dining takes place in covered tents. The SARS-CoV-2 virus that causes COVID-19 mostly spreads from person to person. The virus is transmitted from infected people when they cough, sneeze, talk, or sing, which can be transmitted through droplets in the air: droplets that fall and then are transmitted through surfaces, or through airborne transmission, which is when droplets are very light and remain suspended. An individual who might be in close proximity to an infected person can then inhale the virus and get infected themselves, or touching their nose, mouth, or eyes after touching the virus. The virus can even spread through people who do not show any symptoms but are infected with COVID-19. When dining indoors with individuals outside of your household, the risk for transmission of COVID-19, particularly through airborne transmission, is increased substantially compared to outdoor dining and dining at home. Covered tents that hold multiple tables at once have the possibility of being slightly safer than a fully insulated, indoor restaurant, but it depends on the design of the tent, and is still a risk given that multiple people from different households are sharing space without being in fully open outdoor air.  Single-table tents are still a risk if they are not aired out for at least three hours before seating a new table, as COVID-19 that is aerosolized can remain in the air for up to three hours. If the three-hour time span is allotted for airing out single-table tents, the method is only effective if they’re used by individuals of the same household, and even then there’s a non-zero chance that COVID-19 could still be in the air if someone from a previous sitting was infected.  The U.S. CDC ranks on-site dining with indoor seating capacity reduced to allow tables to be spaced at least 6 feet apart, and/or on-site dining with outdoor seating, but tables not spaced at least six feet apart as high risk, and ranks on-site dining with indoor seating or with seating capacity not reduced and tables not spaced at least 6 feet apart as highest risk. Design concerns to consider with regards to COVID-19 safety include airflow, which is extremely important for ventilating a space and decreasing risk (eg. three walls of tent seating as opposed to a fully enclosed four makes a significant difference); the number of people allowed in the space (the fewer people, the better); the distance between tables (at least 6 feet and the further the better); humidity levels, if relevant (the more humid, the better); and if the restaurant has explicit rules around mask use and safety.

Why would it have been hard for AstraZeneca to discover blood clots in clinical trials?

The AstraZeneca vaccine went through rigorous Phase 3 testing and regulatory approval processes before being administered in the general public where it has been approved. In the reported Phase 3 trial data of more than 23,000 people, a total of 175 severe adverse events were reported (84 in the study group, 91 in the control group). Three events were considered possibly related to either the control or experimental vaccine. These events included one case of hemolytic anemia (in the phase 1/2 study control group), one case of transverse myelitis (in the study group 14 days after the second vaccine dose), and a case of high fever without another diagnosis (the patient information remains masked as part of the trial). Blood clots were not mentioned in the study published online on December 8, 2020. In clinical trials, it can be very difficult to identify uncommon side effects or serious adverse events (or reactions). When an event is uncommon, it can take a very large study group for it to be observed in research even once. Vaccine studies are designed to evaluate if the vaccine works, and if it is safe. COVID-19 vaccines were studied in clinical trials with thousands of participants before emergency use approval. Even with diverse and large study groups, it is possible that some side effects, reactions, or serious adverse events may not have been seen in the study population. Events that only occur in a few people out of a million or more can be very difficult to detect. In statistics there is a formula that is sometimes used to estimate how many people would need to be studied to detect a serious adverse reaction (SAR). The formula is called the rule of three. For example, if a medication were to cause a SAR in 1 person in every 1,000, then a company would need to study 3,000 people (the rule of 3) in order to have a 95% chance of observing or detecting even one case. For even more rare events that may occur in 1 person in every 10,000, a company would need to study 30,000 people to have a 95% chance of observing or detecting one case. For comparison, the type of rare blood clotting that was observed is estimated to occur in only a few people out of every million.  To help understand more rare adverse effects, drugs and vaccines are studied even after they are approved for the public. Data collection continues for years. This Phase 4 study (or observation) continues as the sample size of the study population is much larger, currently in the many millions for the COVID-19 vaccines. Researchers are continuing to gather data and information about events that occur in people who have received the vaccine. In Epidemiology: An Introduction, a text by Kenneth Rothman, the author notes that a lot of the data around drug safety “comes from studies that are conducted after a drug is marketed.” For the COVID-19 vaccines, government agencies (like the U.S. Food and Drug Administration and others) are collecting data about possible adverse events. Suspected adverse events are reported to the agency, and the agency investigates further. A reported or possible association does not mean that a vaccine caused an event to happen.  Trained researchers monitor and analyze data from these reports. They try to evaluate whether it is likely that the reaction was caused by the vaccine. To do so, they study the possible pathways that could cause the reaction to occur. They also compare the probability of the reaction in those who have been vaccinated to the probability of the reaction in those who have not. Now that many millions of people are being vaccinated with the new COVID-19 vaccines, it is not surprising that some rare events, like allergic reactions and blood clots, are being reported. Researchers now need to work to determine if the events are related to the vaccines and why. Many thousands of blood clots are diagnosed every year. Immobility, surgery, obesity, and smoking are some of the many risk factors. According to the European Medicines Agency, it is possible that blood clots could also be related to receiving the AstraZeneca COVID-19 vaccine. There has not been evidence of issues related to specific batches or a particular manufacturing site for the AstraZeneca vaccine. As of April 4, 2021, a total of 222 cases of thrombosis (169 cases of cerebral venous sinus thrombosis and 53 cases of splanchnic vein thrombosis have been reported) have been reported to EudraVigilance - the European system for managing information about serious adverse reactions to medicines. About 34 million people had been vaccinated in the European Economic Area and United Kingdom by this date.  On April 7, 2021, the European Medicines Agency safety committee concluded “that unusual blood clots with low blood platelets should be listed as very rare side effects of Vaxzevria (formerly COVID-19 Vaccine AstraZeneca).” The U.K. regulatory agency recommended alternatives to the AstraZeneca vaccine to be given to people under 30 years of age, following 79 reported cases of blood clotting and 19 deaths. As of April 16, 2021, the Australian regulatory agency is also conducting a review of the AstraZeneca vaccine following three reported instances of rare clotting, including one fatal case. AstraZeneca has not applied for regulatory approval in the United States, but another viral vector vaccine for COVID-19 made by Johnson & Johnson is also under review for rare blood clotting as of April 13, 2021. Regulatory agencies take vaccine safety seriously and often exercise an abundance of caution. COVID-19 vaccines have been credited with saving lives and reducing hospitalizations on a large scale. 

What do we know about COVID-19 reducing life expectancy?

Life expectancy is the estimated number of years that a person can expect to live based on their current age in a specific place. Life expectancy is often measured in two ways. The first way is called Period Life Expectancy and it is calculated by measuring how frequently people died in a specific group in a specific time and then multiplied to represent an entire population. The second way life expectancy can be measured is through using a Cohort Life Expectancy approach and this is measured by calculating mortality risks throughout the lifetimes of a group of individuals born during the same period of time. Because of advances in medical treatment, before 2020, period life expectancy was increasing in many parts of the world. As a result of deaths that have happened during the COVID-19 pandemic, many experts have said that period life expectancy values will decrease, at least temporarily. While period life expectancy is commonly used to report on population health, it is a projection that cannot account for any future changes in mortality (or death), unlike cohort life expectancy. The period life expectancy measure assumes that the number of people in any age group who die in one year will be the same the following year and so on. For example, many people died from COVID-19 in 2020, but with vaccines and other improved methods of prevention and treatment, the number of deaths may be less in 2021. If this is true, the period life expectancy would likely increase again. On February 25, 2020, the U.S. CDC reported that the period life expectancy in the United States fell by a full year in the first six months of 2020 -- from 78.8 years in 2019 to 77.8 years. This period life expectancy reflects the average life expectancy for an infant born in 2020. The value does not mean that everyone who is alive now will die one year earlier. Changes in period life expectancy were reported between males and females. In 2019, female period life expectancy was 5.1 years higher than for males (76.3). In 2020, female period life expectancy was 5.4 years higher than for males (75.1 years for males and 80.5 years for females). Differences in life expectancy were also reported based on  race and ethnicity. Life expectancy decreased most for Black individuals, then Latino individuals, then white individuals. As a result of these differences in decreases, the Latino population had a lower period life expectancy advantage compared to the white population by about a year as of the first half of 2020. The white period life expectancy advantage compared to the black population increased by nearly two years to a 6 year difference overall. This is the widest period life expectancy has been between Black individuals and white individuals in the population since 1998. The CDC life expectancy estimates were specifically based on information for the first half of 2020. When remeasured in 2021, life expectancy as well as cohort life expectancy are likely to decrease alongside decreases in COVID-19 deaths and increases in COVID-19 vaccinations. 

What do we know so far about the variant of COVID-19 first identified in South Africa?

There are many thousands of COVID-19 virus variants that exist, most of which are not concerning. However, experts are concerned about a variant that is dominant in South Africa, also known as 501.V2 or B.1.351.  This variant was first identified in Nelson Mandela Bay, South Africa, in samples that date back to the start of October 2020. It has since become the dominant virus variant in the Eastern and Western Cape provinces of South Africa and spread outside of South Africa to at least 20 countries, including the U.S., Norway, Japan, the U.K., and Austria. Most variants are not significant and in some cases can even weaken the virus. The South African variant is one that appears to be more contagious and more evasive of current vaccines. Its contagiousness is due to a mutation in the virus's spike protein that makes it easier to spread. The UK variant also has this protein, making the variants similar. There is no evidence so far to suggest that the South African variant causes more severe or more deadly cases of COVID-19. In a pre-print study of the Pfizer vaccine using blood samples from vaccinated individuals studying protection against two of the South Africa variant mutations, efficacy was just slightly less than the original 95%. Early results from a Moderna study of the vaccine’s efficacy against the variant suggest around the same efficacy (94.1%), although the immune response may not be as strong or prolonged.  Early results for Novavax and Johnson & Johnson suggest some protection but reduced. Testing for the Novavax vaccine suggests a reduction from 89.3% efficacy against the virus to 60.1% efficacy against the variant, and early results from the Johnson & Johnson testing suggest a reduction from 72% efficacy to 52%. And finally, preliminary data on protection from Oxford’s AstraZeneca's vaccine suggests that it offers limited protection against the South Africa variant when mild disease is triggered, but experts state that it should still protect against severe disease.

What do we know about 2008 references to SARS-CoV-2 and SARS-CoV-3?

SARS-CoV-2, the virus that causes COVID-19, emerged in late 2019 and caused a global pandemic starting in early 2020. Following the current scientific naming convention, there has been no virus identified as SARS-CoV-3 as of early 2021. In 2008, a study was published by Chinese scientists funded by the European Commission as part of the Sino-European Project on SARS Diagnostics and Antivirals (SEPSDA). The study used the terms SARS-CoV1, SARS-CoV2, and SARS-CoV3. These numbered SARS-CoV terms refer to gene fragments of SARS-CoV-1, the virus that causes severe acute respiratory syndrome (SARS). The 2008 study focuses on a method of packaging an RNA sequence that could reduce labor costs. It is unrelated to the SARS-CoV-2 virus. SARS-CoV-1, originally referred to as simply SARS-CoV, was first identified during the SARS outbreaks of 2002-2004. SARS-CoV-2, originally referred to as 2019-nCoV, because it was a novel coronavirus that emerged in 2019, is a different virus from SARS-CoV-1. In a scientific consensus statement published by Nature in 2020, SARS-CoV-2 was renamed after being recognized as a sister to other respiratory syndrome-related coronaviruses, including SARS. The recognition took place based on phylogeny (the study of evolutionary relationships between biological entities), taxonomy and established practice. SARS-CoV-1 and SARS-CoV-2, while related, are different viruses and just two of many coronaviruses (named for crown-like spikes on the surfaces) in the RNA virus family of Coronaviridae.

Where can I find information on adverse reactions from the vaccines? How are they being reported and made public?

Most regulatory policies require COVID-19 vaccine candidates to go through rigorous clinical trials, which include documentation of adverse reactions. The vast majority of participants in COVID-19 vaccine clinical trials did not experience severe adverse reactions. Results from the clinical studies are published and publicly available. One platform that consolidates the results is the COVID-19 Real-Time Learning Network, which is made available thanks to a collaboration between the U.S. Centers for Disease Control and Prevention (CDC) and the Infectious Diseases Society of America (IDSA). Additionally, now that COVID-19 vaccine candidates have been given to millions of people around the world, more data is becoming available from countries that are monitoring the vaccine distribution and collecting information. For example, in the United States, adverse reactions can be reported by providers of the COVID-19 vaccines, as well as by recipients on the national VAERS (Vaccine Adverse Event Reporting System) online platform. This reporting system is part of the many expanded vaccine safety monitoring systems that have been developed. Based on early data from these reporting systems, the U.S. CDC released a report in January 2021 on anaphylaxis, a severe and potentially life-threatening allergic reaction that rarely occurs after vaccination. This report is publicly available, along with several other reports and resources, and includes recommendations such as ensuring that patients with previous history of similar allergic reactions are monitored for 15-30 minutes following COVID-19 vaccination and are taught how to recognize signs of anaphylaxis. If someone has questions about potential adverse reactions because of their health status, including any pre-existing health conditions, please consult with a healthcare provider. If someone has received a COVID-19 vaccine dose and has experienced serious adverse side effects, please consult with a healthcare provider and report the adverse effects to a vaccine safety monitoring system as appropriate. For reference, the U.S. CDC has provided a list of what is normal to expect after COVID-19 vaccination, including typical minor side effects: <https://www.cdc.gov/coronavirus/2019-ncov/vaccines/expect/after.html>

Why are some people testing positive for COVID-19 after taking a COVID-19 vaccine?

There are a few main reasons why someone may test positive for COVID-19 after taking a COVID-19 vaccine.  1. The vaccines that are currently most widely distributed—the Moderna vaccine and the Pfizer-BioNTech vaccine—are reported to have about 95% efficacy. This means that about 5% of vaccinated people are still likely to contract COVID-19. As a result, some individuals are testing positive for COVID-19 despite having gotten a vaccine. The chance of hospitalization or death in a vaccinated COVID-19 patient is significantly lower than an unvaccinated COVID-19 patient. 2. After someone gets the shot, it takes time to build up immunity to COVID-19. The full benefits of the vaccines aren't reached until two weeks after the second dose of the Moderna vaccine and 7 days after the second dose of the Pfizer-BioNTech vaccine. In the time leading up to maximum immunity, the chances of contracting COVID-19 are not zero. 3. COVID-19 vaccine efficacy rates published by pharmaceutical companies do not yet tell us the exact vaccine effectiveness rates that can be expected in actual populations. As a result, it is possible that the number of individuals (5%) who are estimated to still contract COVID-19 despite being vaccinated could actually be different in the population. No vaccine is perfect, and there are a range of factors that contribute to chances of the vaccine not working, such as weakened immunity and viral load exposure.  It is highly unlikely that false positives are contributing to the numbers of vaccinated individuals testing positive, given that neither the Moderna nor the Pfizer-BioNTech vaccine cause you to test positive on a viral test. Public health professionals advise wearing a mask and maintaining physical distance even after getting vaccinated, in order to protect those that are not vaccinated as yet and to stop further spread in the community.

How are vaccines studied for long-term side effects?

After vaccines are approved for use they are monitored closely by national and international health and medicine regulators. Studying long-term effects of vaccines helps health authorities ensure that protection from taking a vaccine outweighs risks. The United States uses several reporting mechanisms for monitoring long-term vaccine side effects. They include: - Vaccine Adverse Event Reporting System (VAERS) which works as an early warning system to detect possible safety issues with vaccines by collecting information about possible side effects or health problems that occur after vaccination - The Vaccine Safety Datalink (VSD) which helps discover if possible side effects identified using VAERS are actually related to vaccination - The Post-Licensure Rapid Immunization Safety Monitoring (PRISM) system which is the largest vaccine safety surveillance system in the United States and actively monitors a subset of the general population for vaccine impacts - The Clinical Immunization Safety Assessment (CISA) Project which works alongside health systems to consistently monitor and evaluate the safety of vaccines throughout large populations Additionally, the U.S. CDC unveiled V-safe in response to COVID-19. V-safe is a smartphone-based tool that uses text messaging and web surveys to provide personalized health check-ins after you receive a COVID-19 vaccine. Using V-safe allows vaccine recipients to quickly tell the CDC if they are experiencing any side effects after getting the COVID-19 vaccine. Depending on which side effects people are experience, someone from the CDC may call to check on them and get more information.  Monitoring vaccines and reporting any side effects to local and national health agencies is an important part of the vaccine process. Any reports of a potential side effect from a vaccine can lead to health officials issuing new recommendations or warnings, restricting the vaccine, or even recalling it if necessary (but very few vaccines have even been recalled). Though safety and efficacy data are intensely reviewed before vaccines are approved for usage, constant monitoring of their side effects is a necessary step in ensuring the public's safety.

Why are there multiple COVID-19 vaccines?

Dozens of countries have now rolled out mass vaccination campaigns using a variety of vaccines. Knowing this, it makes sense to question why more than one or two or these vaccine formulas are necessary. The answer to this is as multi-faceted as populations are diverse, but in short, we will need multiple vaccines to stop the pandemic. No one pharmaceutical or biotechnology company would be able to produce enough product and distribute it to the entire global population fast enough to curb the pandemic. Producing more than one vaccine also means that manufacturing delays become less risky. With the world relying on multiple companies to produce the live-saving products, delivery delays of one vaccine can be offset by the production of other vaccines. For countries with electricity challenges, last mile health outposts, and a lack of roads, it is not always feasible to deliver Pfizer and Moderna's mRNA vaccines, because of the refrigerated temperatures they require for transport. Many countries will likely rely on another vaccine formulation that has a longer shelf life and has no refrigeration requirements. Cost is another reason for multiple vaccines. High resource-countries have pre-purchased millions of different vaccines directly from distributors in order to immunize their populations, which is not possible for some countries. Vaccine prices range from a couple of US dollars per dose to roughly $50, depending on the producer. Many countries do not have the financial resources to spend billions of dollars in addition to their annual health budgets to procure vaccines for their populations. As such, dozens of countries are reliant on programs like COVAX to help them obtain free or low-cost vaccines for their citizens. Lastly, vaccines need to protect diverse groups of people. Every person will respond differently to each vaccine and have a different immune response. So having a variety of vaccine types fill these needs is a more concrete strategy than relying on or or two vaccines alone. We still have many unanswered questions about how long immunity might last, who might have a more robust immune system response than others, or even how effective they might be in children.

What do we know about the smallpox vaccine?

Smallpox was among the deadliest viral diseases in human history, killing an estimated 30% of the people infected and leaving many survivors with permanent life changes, such as blindness or disfigurement.** ** The smallpox vaccine developed by Edward Jenner in 1796 is considered the first successful vaccine to be created. In the original version, a patient was infected with another disease, cowpox, to induce an immune response that could protect against smallpox. Smallpox vaccines have evolved over time, with some eventually using a different virus called vaccinia (which is similar to cowpox and less harmful than smallpox) to induce a protective immune response. Since smallpox vaccines are considered live virus vaccines, as opposed to weakened (attenuated) or killed (inactivated), more precautions are required when getting this type of vaccine and there are higher risks of severe side effects. Thanks to extensive global vaccination efforts reaching 80% coverage in each country, smallpox was recognized as eradicated in 1980 by the World Health Organization. This means that the smallpox vaccines no longer need to be routinely given, and many people born after this time have not been vaccinated against smallpox.In July 2020, a report was published in Genome Biology about the origins and genetic diversity of some historical smallpox vaccine strains. The authors have stated that "understanding the history, the evolution, and the ways in which these viruses can function as vaccines is hugely important in contemporary times" and that "this work points to the importance of looking at the diversity of these vaccine strains found out in the wild. We don't know how many could provide cross protection from a wide range of viruses, such as flus or coronaviruses."

Why has vaccine rollout been so slow in the European Union compared to other countries?

Globally, the COVID-19 vaccine rollout has been wrought with challenges and unforeseen delays. In spite of the European Union having contracts in place for 2.3 billion doses of COVID-19 vaccines, availability is still limited and rollout has been slow. This is because of a lengthy and complex vaccine approval process, delays in production and delivery, and gaps in planning. Nonetheless, according to the EU vaccine strategy, all adults should be able to be vaccinated during 2021 and the European Commission has promised that “all Member States will have access to COVID-19 vaccines at the same time and the distribution will be done on a per capita basis to ensure fair access.” To be sure, it is difficult to compare the EU to single-country jurisdictions. There are likely to be logistical rollout challenges that are specific to the EU, because one country’s hurdles can directly impact other countries in the Union. While the European Commission has encouraged Member States to follow a common vaccine deployment strategy, there is some tension between supporting a coordinated EU approach while also considering the needs of country-level governments that seek to maintain some autonomy. **Approval process delays:** Both the Moderna mRNA-1273 vaccine and the Pfizer-BioNTech BNT162b2 vaccine have been approved by the European Medicines Agency, but EU approvals for the vaccines have trailed approvals in other countries like the U.S. and Canada. The EU approved the Moderna and Pfizer vaccines weeks after the US and Canada did so. The Astra Zeneca vaccine, which is approved for use in the UK and Canada but not yet in the United States, is also waiting on approval from the EU.  **Delays in production and delivery: **On top of its lengthy approval process, vaccine deliveries to the EU have also contributed to a slower rollout than expected. The AstraZeneca vaccine is nearing the end of the EU regulatory approval process, but the company stated recently that it plans to deliver far fewer doses than it had promised. The change has increased tensions between the vaccine maker and the EU, which pre-financed AstraZeneca’s vaccine development. Though there have not been reports of widespread delays on the Moderna vaccine, Poland reported a delayed Moderna vaccine on January 25, 2021. The new target date for the delayed delivery is during the weekend of January 30-31, 2021, though it is unclear if this will occur as planned.  Ursula von der Leyen, President of the European Commission, speaking at the World Economic Forum on January 26, 2021, highlighted European investments in COVID-19 vaccine development and stated that “the companies must deliver. They must honor their obligations.” She went on to mention plans for a vaccine export transparency mechanism to ensure that vaccine allocations are being delivered as promised. A reorganization at Pfizer led to Pfizer-BioNTech reducing vaccine deliveries to all European countries starting the week of January 18. Pfizer stated in a press release on January 15 that the goal of the reorganization is to “scale-up manufacturing capacities in Europe and deliver significantly more doses in the second quarter.” As a result, a Pfizer vaccine manufacturing facility in Puurs, Belgium experienced a temporary reduction in the number of doses delivered beginning the week of January 18, set to end the start of the following week, (January 25) with the original schedule of deliveries resumed. The reorganization’s impacts were not exclusive to the EU, however, given that Pfizer’s Belgian plant supplies all vaccines delivered outside of the U.S.. Canadian officials claimed that the reduction would halve the number of vaccines they received over late January and February, and Norwegian officials also released a statement about the reduction. Italy threatened legal action. Though the reduction was set to last just one week, Pfizer noted that the reorganization would “temporarily impact shipments in late January to early February.” The company stated that to help compensate, it will significantly increase doses available for EU patients in late February and March.  Given that rollouts have been slow in a number of individual EU countries, such as Germany, the Netherlands, and France, this announcement placed more pressure and concern on the in-country programs and EU vaccine rollout overall, which has been criticized for not purchasing more vaccines. It also complicates the timing of second dose vaccinations for healthcare workers and elderly individuals, and, as a result, the overall vaccine distribution timeline. **Gaps in planning: **A December 2020 report published by the European Centre for Disease Prevention and Control, which looked at the EU, the European Economic Area, and the United Kingdom, stated that only Bulgaria, Hungary, Malta, the Netherlands, and Sweden were found to have existing infrastructures sufficient enough for deployment of the COVID-19 vaccines. (All 31 surveyed countries had begun deployment and vaccination plans for COVID-19 vaccines in anticipation of approvals and deliveries beginning in late 2020.)  Many countries planned to employ existing vaccine infrastructure during the COVID-19 vaccine rollout, and several countries were aware of gaps in equipment to accommodate the ultra-low temperature requirements of some COVID-19 vaccines.  Delivery systems, priority populations, human resource requirements, monitoring systems, and levels of preparedness for the vaccine rollout varied widely among surveyed countries. Unsurprisingly, these differences have the potential to influence how vaccines are provided to residents and can explain some of the variation observed across the EU. The European Centre for Disease Prevention and Control continues to support COVID-19 vaccination across the EU and has provided support to Member Countries through research and planning activities as well as collaboration with the World Health Organization Regional office for Europe, the European Medicines Agency, and the EU/EEA National Immunisation Technical Advisory Groups. The report also found that as of November 30, 2020, only 9 EU countries had published interim recommendations for priority groups to be considered for vaccination. The other countries were in the process of developing such plans. Pfizer and BioNTech reached an agreement with the European Commission to supply 200 million doses of a vaccine in November 2020, and the first COVID-19 vaccine to be approved in the EU (the Pfizer-BioNTech vaccine) was approved on December 21, 2020.

Could shaking, convulsions, and tongue spasms really be side effects of a COVID-19 vaccine, specifically Moderna's?

Vaccines imitate real infections in our bodies, and they can sometimes cause minor symptoms in people. This happens because, in trying to fight off the imitation infection, some bodies develop real symptoms. As of January 25, 2021, almost 55 million doses of the Pfizer and Moderna vaccines have been given to help protect people from a COVID-19 infection. Within this group, medical research has not found the symptoms of shaking, convulsions or tongue spasms as known side effects of the vaccine. The United States Centers for Disease Control and Prevention and the Food and Drug Administration have said that these symptoms have not been documented in any reported vaccine patients and are not in line with the list of side effects noted during clinical trials. Additionally, the United States Vaccine Adverse Event Reporting System has yet to receive any reports from patients that list these side effects after they received their vaccines. However, it is recommended that anyone who has had previous allergic reactions to vaccines to not receive an injection of the COVID-19 vaccine, because in very few cases they can cause allergic reactions. When vaccines are distributed at scale, the way they currently are for COVID-19, some little known side effects may be reported during the rollout. Those side effects may or may not be related to the vaccine itself. Despite national health, medical, drug regulatory agencies and pharmaceutical companies noting that side effects like convulsions and shaking are not listed and have not been reported, it is important for anyone experiencing any severe side effects to report them to their physician and drug regulatory agencies and seek medical care immediately. While vaccine side effects are often minimal, fevers and pain at the injection site sometimes occur after vaccination. Severe side effects are rare and must be quickly reported to the patient's physician and national medication regulatory agencies.

What do we know about the mRNA vaccine and cytokine storm?

There is no evidence to suggest that mRNA COVID-19 vaccines or non-mRNA COVID-19 vaccines would result in cytokine storms.  Cytokine storms happen when outside pathogens trigger an overproduction of proteins called cytokines. This overproduction can result in damaged lung tissue, acute respiratory distress syndrome, and death. While no single definition of cytokine storm is widely accepted, three features of cytokine storms are commonly shared: elevated levels of cytokines, acute systemic inflammatory symptoms, and either secondary organ dysfunction or any cytokine-driven organ dysfunction. Although the mechanisms of lung injury and organ failure in COVID-19 are still being studied, data suggest that cytokine storms contribute to the development and severity of COVID-19 in some patients.  One hypothesis about cytokine storms is that they are a consequence of a process through which antibodies bind to viruses and give them easier entry to cells instead of attacking them, which incites a harmful immune response. This is called antibody-dependent enhancement (ADE). Scientists are not yet completely sure if ADE actually promotes cytokine storms and are also considering other factors that may play a role.  ADE and cytokine storms can result naturally due to a range of underlying causes; however, there is no evidence that they would result from an mRNA COVID-19 vaccine, or any COVID-19 vaccine. In very rare cases, ADE has resulted from vaccines, such as the Respiratory syncytial virus (RSV) vaccine in the 1960s and the Dengue vaccine in 2016, due to Dengue's four strains. Today’s routinely recommended vaccines, however, do not cause ADE, and Phase 3 trials are designed to specifically detect such negative outcomes.  Neither Moderna nor Pfizer-BioNTech, the two leading biopharmaceutical companies that produced the mRNA COVID-19 vaccines being distributed, found any evidence of ADE or cytokine storm from any trial phase. In addition, rates of disease were significantly lower in the vaccinated group, and among those who did contract COVID-19 in the vaccinated group, rates of severe disease were lower than in the placebo group. Scientists and public health professionals will continue to closely monitor vaccinated individuals to ensure that ADE and cytokine storms can be entirely ruled out as a side effect of COVID-19 vaccines. For the moment, however, there is no evidence that shows the vaccines to have such effects.

What do we know about the vaccine clinical trials for people of various ethnicities and in various countries around the world?

During clinical trials for drug or vaccine development, testing is done on recruited participants in settings controlled by investigators, meaning that the studies do not necessarily reflect real-world populations and conditions. There are many factors to consider when evaluating the safety and efficacy of COVID-19 vaccines, such as race and ethnicity, sex and gender, age, and different health conditions. Race and ethnicity are believed to be important to consider when evaluating vaccine candidates. For example, with previous vaccines for influenza, a study found that race-related differences in immune responses to the vaccines were linked to genes being expressed differently in African Americans and Caucasians. It is possible that there could be differences in immune responses to the COVID-19 vaccines, so there is a need for diverse participants in clinical trials. Unfortunately, clinical trials have mostly recruited a limited pool of people for participation, historically as well currently. There have been efforts to diversify the race and ethnicity of participants in COVID-19 vaccine trials, but there remain inequities in who has sufficient information to provide consent as well as who has the time and resources (such as transportation access) to participate. Additionally, there can be a lack of trust for participation due to the history of exploiting racial and ethnic minorities, such as the infamous Tuskagee syphilis that hurt many African Americans in the U.S. Globally, drug development and clinical trials have taken place mostly in countries with more financial resources, historically as well as currently. There have been efforts to address some of these inequities, such as COVID-19 vaccine manufacturers running clinical trials with participants recruited from multiple countries. Unfortunately, there is still limited data about the safety and efficacy for people in certain parts of the world, because fewer participants there have been able to participate in clinical trials. Clinical trial participation must be diversified, in order to understand how different people around the world will be impacted when given the COVID-19 vaccines.

How do mRNA messenger vaccines work?

A vaccine’s role is to teach the immune system how to recognize a foreign body (the coronavirus in this case) that could make a person sick. Once the immune system is able to identify a harmful invader, it can attack the actual virus if it enters the body. Most vaccines are made from an inactivated or weakened pathogen (bacteria or virus). Because the virus in the vaccine is weakened or inactivated, they don’t cause severe disease in the body but are able to train the immune system to recognize the invader and be able to fight it by creating antibodies. These antibodies are a special kind of protein that know how to fight that specific virus. The immune system then remembers to make these antibodies in case such virus does enter our body in the future, and thus prevent disease. mRNA vaccines or "messenger RNA" vaccines are different. They're a type of vaccine that does not carry an inactivated or weakened pathogen. Instead, they carry information, which instructs the cells in the body to create a protein or a part of a protein, which in turn triggers an immune response. Teaching the cells to create this harmless but foreign protein allows the body to activate its immune system. On seeing a foreign element in the system, the immune system fires into action and starts producing antibodies to fight against the invader. Soon after making the protein, our cells break down the mRNA and get rid of it. mRNA COVID-19 vaccines cannot cause COVID-19 because they do not carry the full information needed to make the SARS-CoV-2 virus in the body. They only carry information from a specific protein found on the surface of the SARS-CoV-2 virus. mRNA vaccines are faster to produce (about a week) as compared to conventional vaccines that can take many months to produce an experimental batch. The production of mRNA vaccines is safer than traditional vaccine production as it doesn’t require actual viruses, whereas, producing traditional vaccines require growing large quantities of actual virus and can pose to be a potential biohazard. Although traditional vaccines are very effective, it has been posited that mRNA vaccines could create an even stronger immune response to certain viruses, but more evidence will need to be gathered on that. One challenge of mRNA vaccines is that it is very fragile and needs to be stored at very cold temperatures.

What do we know about how curfews work?

The intended purpose of curfew orders is to reduce nonessential interactions between individuals from different households by keeping people at home during a time when they are more likely to participate in nonessential activities that could result in less compliance with public health practices. The logic of this argument is that people are more likely to be working during the day and running essential errands such as grocery shopping, whereas in the evening and early hours people are less likely to be gathering for essential reasons, and are more likely to be gathering socially with a risk of leniency towards public health recommendations and mandates. Contact tracing efforts have shown that the most common sources of COVID-19 spread include gatherings at places such as bars and restaurants. In addition, the percent positivity of COVID-19 is highest among 18 to 24-year-olds across counties in the United States—the country with the most cases and deaths of COVID-19—indicating high public health need to target that age group, which curfews do.  By maintaining most normal activities, curfews also have less of a negative financial and mental health impact on society than lockdowns. Curfews also signal the severity of the situation, and as a result, are potentially helpful for reducing interactions between people overall.  One critique of curfews, particularly ones that start early in the evening, is that for a short period of time before a curfew begins they can result in more people being crammed together (on transit, in stores, etc.) who are rushing to get errands done and get home on time. In addition, jurisdictions close by (such as neighboring cities) can have different curfews, making it difficult to really ensure the curfew is effective as an individual with an early curfew could stay out in a neighboring city with a later curfew. It could also create difficulty for local businesses when curfews differ and one jurisdiction’s businesses are able to stay open later than others'. In addition, individuals can go around the curfew, for instance, by gathering in homes after the start of curfew.  Overall, there isn’t strong evidence that curfews help or hurt efforts to curb the spread of COVID-19. There are pros and cons to curfews, with logical reasons pointing towards their use. However, targeted actions such as limiting indoor dining or cracking down on large indoor gatherings are more likely to be more effective.

What do we know about arthritis drugs (including tocilizumab or sarilumab) as a treatment for severe COVID-19?

Tocilizumab and sarilumab are drugs used for arthritis treatment that have shown potential to reduce deaths among severely ill COVID-19 patients. Several clinical trials around the world are underway to study the effect of tocilizumab and sarilumab to treat severe SARS-CoV-2 infection. There have been mixed results about their efficacy to treat COVID-19 based on the studies conducted so far. A recent study of 800 patients conducted in the UK has shown encouraging results. As per the pre-print, which has not been peer-reviewed yet, hospital mortality among critically ill patients with COVID-19, who were on organ support in intensive cares, had better survival rates (28% and 22.2% respectively for early tocilizumab and sarilumab treatments) compared to those who were not treated with these drugs (35.8%). Based on the available research evidence, the U.K. NHS has encouraged the use of tocilizumab and sarilumab to support the treatment of patients with COVID-19 who have been admitted to intensive care units. Tocilizumab and sarilumab are immunosuppressor drugs, that work to suppress a protein called IL-6. When a virus infects a body and starts replicating itself, the immune system response activates, which in the case of severe infections may then lead to an inflammatory response, where the immune system starts attacking the body’s own cells. In case of severe COVID-19 illness, some patients experience a self- damaging cytokine response with very high levels of IL-6. These drugs help to inhibit such a response.

Should someone still get the first dose of a COVID-19 vaccine, without assurance that a second dose will be available?

For COVID-19 vaccines that are designed to have two doses, it is important to get both doses to maximize protection. In late 2020, the U.S. Food and Drug Administration (FDA) authorized emergency use of COVID-19 vaccines from Moderna and Pfizer / BioNTech, both of which are designed to be implemented in two-doses.  Studies have shown each of these vaccine candidates to be relatively safe and ~95% effective at preventing symptomatic COVID-19 disease in adults after both doses. There are many reasons why a second dose may become delayed or unavailable due to issues like limited vaccine supply and other logistical challenges. As a result, there are proposals to ration vaccine doses or to initially give a single dose to as many people as possible. The reaction of scientists to these proposals is mixed, because of limited data on the impacts of changing recommended vaccine dosing. According to data provided by Moderna, one exploratory analysis of participants who received just one dose of its vaccine suggested that the efficacy in protecting against symptomatic COVID-19 could be around 73%, in the short-term. Efficacy in protecting against symptomatic COVID-19 after the first dose of the Pfizer vaccine was about 52.4%, with most of the cases happening in the days immediately following the first dose. From day 10 after the first dose until the second dose, the efficacy in protecting against symptomatic COVID-19 was around 89%.  It is important to note that the second dose was given on day 21 in these Pfizer / BioNTech trials, so there is limited data on how well the first dose would protect someone after day 21.   On January 4, 2021, the FDA issued a statement about following the authorized vaccine dosing schedules, saying: “We have been following the discussions and news reports about reducing the number of doses, extending the length of time between doses, changing the dose (half-dose), or mixing and matching vaccines in order to immunize more people against COVID-19. These are all reasonable questions to consider and evaluate in clinical trials. However, at this time, suggesting changes to the FDA-authorized dosing or schedules of these vaccines is premature and not rooted solidly in the available evidence.” More research is being done to help answer the question about how beneficial it is to change a recommended vaccine dosing schedule in order to stretch limited supplies to as many people as possible. 

How does Pfizer identify cases of COVID-19 in its clinical trials?

Clinical trial researchers have standard definitions for routinely detecting COVID-19 cases for both symptomatic and asymptomatic individuals. There are three ways that researchers classify and identify symptomatic COVID-19 cases in clinical trials. Criteria for the first classification includes: the presence of at least one COVID-19 symptom and a positive COVID-19 test during, or within 4 days before or after, having symptoms. The second classification is the same, but also includes four additional COVID-19 symptoms defined by the CDC (fatigue, headache, nasal congestion or runny nose, nausea). Criteria for the third classification, which identifies severe COVID-19 cases in clinical trials, includes a confirmed COVID-19 test (per the above guidelines), as well as one of the following symptoms: clinical signs of severe systemic illness, respiratory failure, evidence of shock, significant acute kidney, liver, or brain dysfunction, admission to an ICU, or death. The Pfizer research protocol states individuals who do not clinically present COVID-19 (that is, asymptomatic individuals) are tested for COVID-19 antibodies. A positive asymptomatic case is defined as the presence of antibodies in an individual who had a prior negative test. By using these four definitions, researchers are able to detect COVID-19 cases in both symptomatic and asymptomatic individuals. However, the pharmaceutical company has stated that there are more data on the vaccine’s safety and efficacy for symptomatic cases, and that more data is needed to better understand the vaccine’s safety and efficacy for asymptomatic cases.

Is it safe or effective to get a vaccine dose for COVID-19 while testing positive?

The U.S. Centers for Disease Control and Prevention (CDC) does recommend that people who have had COVID-19 still get vaccinated, because it may be possible to get reinfected and vaccines can sometimes induce better immunity than natural infection. However, this recommendation typically applies to people who have recovered from COVID-19, rather than people who are currently still sick. For people who currently have an active COVID-19 infection, their bodies are already creating antibodies in response, so health experts recommend waiting until after recovery for vaccination. Researchers are still understanding how immunity evolves over time, but it is generally thought that most people have some level of protection against reinfection for the first few months after recovery. The U.S. CDC even suggests that people who have not had COVID-19 in the past 90 days should be a higher priority for vaccination than people who have had COVID-19 recently. Additionally, it takes time for the body to develop immunological protection after vaccination, and vaccines requiring two doses do not have maximum protection until after the second dose. This means that it is still possible for someone to become sick if exposed to COVID-19 before or immediately after vaccination. People who are known to have COVID-19 may not be able to go receive vaccinations until after they recover because they could risk getting others sick. Scientists are continuing to learn about the safety and efficacy of COVID-19 vaccines with the ongoing studies and data collection. For vaccines that have been approved by regulatory agencies and are already in the market, phase 4 clinical trials (also called “open-label studies” or “post-marketing surveillance”) are a way to continue studying the risks and potential benefits over a longer period of time. More data will become available in the future. 

Why was Pfizer's vaccine developed so quickly, and why should this speed not worry the public?

On January 11, 2020, the CEO of BioNTech Dr. Ugur Sahin, designed 10 different possible candidates for a COVID-19 vaccine in one day. Two of them were selected for study in initial COVID-19 vaccine trials, and one (the mRNA-1273 vaccine) advanced onwards to trial phase 2/3, and has now been approved for emergency use in countries around the world such as the UK, Israel, Singapore, and the US, with other authorizations pending. In addition to the vaccine's rapid design, the timeline from start to approvals (under one year) is also the shortest overall vaccine timeline ever. There are two primary reasons that the Pfizer vaccine was developed so quickly: 1) The use of mRNA vaccine technology, and 2) the rapid sharing of the COVID-19 virus’ genetic sequence.  The mRNA-1273 vaccine works by injecting genetic information from the coronavirus into human cells. This instructs the body to make special spike proteins like the coronavirus, and causes the immune system to respond effectively against the virus. This specific method means that BioNTech only needed the genetic sequence of the COVID-19 virus to design a vaccine. Other methods involve more timely processes, like weakening or killing a virus, or producing part of the virus in the lab.  The mRNA process involves slotting genetic material from the virus into a tested and reliable delivery “package.” The process, also known as an mRNA vaccine “platform technology,” is not the most traditional vaccine approach, but has been in development for over 20 years.  mRNA vaccines are non-infectious, so this type of vaccine can have safety benefits over conventional vaccines that contain weakened or inactivated germs. Production for mRNA vaccines is also cell-free and tends to be faster, cheaper and easier to scale than cell-based vaccine manufacturing techniques (ex. inactivated influenza vaccines are typically grown in cultured cells).  China’s initial rapid identification of the genetic sequence and early sharing of the sequence globally on January 10, 2020, prior even to the understanding of human-to-human spread of COVID-19, promoted rapid availability of this critical vaccine development data. The speed of the Pfizer vaccine timeline was also aided by other factors, such as ongoing work studying coronaviruses, a growth in preprint publications (where researchers can share findings before the peer-review publication process is completed), and the unprecedented scale of COVID-19 that continues to infect, harm, and kill people across the world, leading to more resources being allocated to preventing and treating COVID-19 and well as expedited logistical timelines. There are multiple, clear, reasons that explain both the quick design of the Pfizer COVID-19 vaccine and the quick overall Pfizer COVID-19 vaccine timeline, none of which jeopardize the safety or efficacy of the vaccine.

What do we know about rationing doses of the COVID-19 vaccines?

Scientists and public health practitioners are considering vaccination tactics that differ from those that the FDA and other country’s health regulatory bodies approved. The tactics being considered are primarily halving doses of vaccines and delaying second doses to get first doses to more individuals, but also include reducing the number of doses and mixing and matching doses.  Health officials in the UK have already decided to delay second doses of two vaccines, one made by AstraZeneca and one made by Pfizer and BioNTech, and to mix and match the two vaccines for the two doses under limited circumstances. This decision has received mixed responses from scientists and public health practitioners, many of whom are concerned about the lack of data, particularly with regards to a mix-and-match approach. Moncef Slaoui, scientific adviser of Operation Warp Speed, the U.S. effort to accelerate COVID-19 vaccine development and distribution, proposed distributing half-doses of the Moderna vaccine (50 micrograms versus 100 micrograms) on Sunday, December 3, as an approach to increasing the amount of vaccinations available. In support of this approach, Slaoui cited that the Moderna study compared the immune response in people given 50 micrograms against those given 100 micrograms of the vaccine, and that the doses yielded identical responses.  However, the trials primarily focused on studying 25 micrograms and 100 micrograms, and the U.S. Food and Drug Administration (FDA) which would have to approve the shift in vaccine distribution stated that this data was insufficient to justify a shift to halving doses or other proposed regimen changes designed to stretch out doses at this point, as of January 6, 2020. The data on the 50 microgram doses comes from the Phase 2 study by Moderna, that was tested on hundreds of people versus tens of thousands tested with the 100 micrograms in Phase 3, and was designed to test only for immune response and not efficacy of the vaccine.  On the evening of late Monday, January 4, 2021, the U.S. FDA critiqued the idea of halving the doses of the Moderna vaccine, saying that the idea was “premature and not rooted solidly in the available science.” Studies are underway to determine whether doses of the Moderna COVID-19 vaccine can be halved to 50 micrograms in order to double the supply of the vaccination doses in the U.S., according to the National Institutes of Health and Moderna.

What do we know about COVID-19 spike glycoproteins and their relationship to the HIV virus?

Glycoproteins, which are a type of molecule made up of proteins and carbohydrates (like sugar), can be found in many viruses. They serve as a way to assist the viruses with entering and binding to the human body. Glycoproteins are found in viruses including SARS (SARS-CoV-1), chikungunya, dengue virus, hepatitis C, ebola, influenza, and more. HIV and COVID-19 have glycoproteins, including spike-like glycoproteins that push out from the virus's surface to attach to cells. However, both COVID-19 and HIV also have distinct genetic codes and different ways of infecting and impacting the people they infect. A recent retracted and debunked study implied that four pieces of genetic code in the COVID-19 virus have striking similarities to genetic sequences found in HIV strains from Thailand, Kenya and India. The research team noted that, similar to those HIV strains, some of the four pieces of code in COVID-19 were found on the spike part of a glycoprotein of the SARS-CoV-2 virus. The debunked study suggested it was likely that scientists manually placed the four genetic chunks into COVID-19 samples from the HIV-1 genome, or in other words, that the virus was created in a laboratory. This study was taken down from its pre-print host site and has been widely debunked for numerous reasons. Though both COVID-19 and HIV have similar spike proteins, with surfaces that are covered by a coat of sugar molecules ( which is how the viruses latch onto and enter human cells) they are not unique to these two viruses by any means. The four DNA protein sequences that the study highlighted are found in many different organisms, including the ones that cause cryptosporidiosis and malaria, in addition to SARS-CoV-2 and HIV. Additionally, the sample of genetic code used in the study was so short and thus not unique, that the code could easily be found in a number of other viruses. A paper rejecting the original study's findings noted that, after a genetic analysis using a more detailed database of genetic sequencing codes, scientists found not just similarities between COVID-19 and HIV, but also at least 100 identical or highly similar codes in genes from mammals, insects, bacteria, and others and in a large number of viruses caused by many different reasons. The paper showed that the genetic codes were not essential for HIV's functions, as they were highly varied and could include many moderations, further disproving the link between HIV being a potential source for SARS-CoV-2's genetic code. Finally, the paper demonstrated that several of the four genetic code insertions were found in bats in 2013 and 2018, so they existed in nature before COVID-19 was even identified, let alone genetically sequenced. Though there are several similarities between HIV and COVID-19 including spike glycoproteins and some similar genetic codes, the scientific community has disproven the idea that genetic codes from HIV could have been altered and substituted into SARS-CoV-2 to cause the COVID-19 virus.

Why is Janssen starting a clinical trial with two doses?

Janssen Pharmaceuticals, part of Johnson & Johnson, has designed a COVID-19 vaccine candidate to be delivered in a one-dose regimen. The company is also starting a clinical trial for a two-dose regimen. Johnson & Johnson announced that the new phase 3 trial for a two-dose regimen has been planned to be complementary and run in parallel with the ongoing phase 3 trial for a one-dose regimen, erring on the side of caution in case two doses have the "potential to offer enhanced durability in some participants." The existing phase 3 trial for a one-dose regimen, called ENSEMBLE, has been enrolling participants with a goal of testing the Janssen vaccine candidate with up to 60,000 people from multiple countries around the world. The newer phase 3 trial for a two-dose regimen, called ENSEMBLE 2, intends to test two doses of the Janssen vaccine candidate with up to 30,000 participants from multiple countries around the world. These ENSEMBLE and ENSEMBLE 2 trials follow the promising interim results from the phase 1/2a clinical trial of the Janssen vaccine candidate, which has been studying both one-dose and two-dose regimens for preliminary data on safety and effectiveness. Due to the urgent nature of the COVID-19 global pandemic, many phases of vaccine development and testing have been implemented in parallel. For example, sometimes clinical trial phases are combined into a phase 1/2 or 2/3 trial, or a later phase trial is started in parallel based on promising interim results of an earlier phase trial (rather than doing trials sequentially that wait for an earlier phase trial to be completed before starting a later phase trial). Johnson & Johnson is not the only major vaccine developer to be running clinical trials in parallel. Scientists will be able to say more about the effectiveness of the one-dose and two dose regimens after more data from the parallel phase 3 trials become available.

What do we know about the risks of combining more than one of the approved vaccines?

For COVID-19 vaccines that require more than one dose, such as the Pfizer-BioNTech and Moderna vaccines, researchers are still learning about the outcomes of mixing a first dose of one vaccine with a second dose of another. In the clinical trials that have led to emergency authorization of COVID-19 vaccines, combining doses from different vaccines has not yet been tested. This means that scientists do not yet know if combining doses from different COVID-19 vaccine candidates will be as effective or safe. To help provide more data, a clinical trial was announced on February 8, 2021 to begin testing the combination of one dose from the AstraZeneca vaccine candidate with one dose from the Pfizer-BioNTech vaccine candidate. This clinical trial, dubbed Com-Cov, is being led by the University of Oxford and is considered the first in the world to test the combination of different COVID-19 vaccine candidates. Enrollment of 820 participants over 50 years of age is starting, and scientists hope this clinical trial can provide more data and insights by the summer of 2021. It is important to remember that outcomes can potentially vary depending on which COVID-19 vaccines are mixed. For this reason, the first clinical trial testing a combination of the AstraZeneca and Pfizer-BioNTech vaccine candidates may eventually add additional vaccine candidates. As more COVID-19 vaccine candidates become ready for approval, more studies may be needed to understand the outcomes of combining doses between the multiple available vaccine candidates. There are many potential benefits to being able to combine COVID-19 vaccine candidates, which is why scientists are eager for more data to evaluate this. Ramping up COVID-19 vaccine supplies and coordinating distribution remain a challenge, so being able to give vaccines based on availability could mean more people receive the vaccinations faster and more lives are saved. The U.K.'s deputy chief medical officer has said that there may be benefits to having data that could support more "flexible" vaccination programs, since there is currently an insufficient global supply of COVID-19 vaccines. Beyond the logistical benefits, there could potentially be immunological benefits of using two different vaccines to combat the same pathogen in certain cases. For COVID-19 vaccines that are given in two doses, the "prime" dose is followed by a "boost" dose to help stimulate and amplify the body's immune response, with the goal of developing immunological memory to protect against COVID-19 infections in the future. The strategy of using doses from different vaccines is known as "heterologous prime-boost." Some COVID-19 vaccine candidates, like the Russian Sputnik V, have even been designed to use this strategy with the first and second doses containing different viral components. With newer and faster-spreading variants of COVID-19 emerging around the world, some of which could be partially resistant to immune responses triggered by the vaccines, scientists are also planning to investigate whether combining different vaccines can help offer more protection. Multiple COVID-19 vaccine candidates have been developed in record speed to help combat the global pandemic. In order to take full advantage of every tool that is available for pandemic response, scientists are studying the potential of combining doses from different COVID-19 vaccine candidates. As more data becomes available, public health experts and policymakers will be able to make more informed decisions about "mixing and matching" COVID-19 vaccine doses.

What does it mean to combine phases of clinical trials during vaccine development?

There are several reasons why scientists might combine clinical trial phases in the process of developing a vaccine. Usually, testing a vaccine occurs in three to four phases after early, preclinical research is done in the lab or on animals, like primates. Phase 1 trials are where researchers try to study very basic elements of vaccines in small groups of people to see how the body absorbs the drug, how long it stays in the body, and to show how toxic the vaccine may be depending on the dosage. Phase 2 trials examine how effective a vaccine is in different doses and looks at short-term side effects, usually with several hundred patients. Finally, phase three trials involve hundreds or thousands of volunteers. They are used to see how well a vaccine may work and what types of side effects are most common over a longer period of time. Phase three trials often determine whether the benefits of a vaccine outweigh the risks. Many vaccines never reach the the third phase as the vaccines might not be shown to be beneficial, may have dangerous side effects, or might not work as well in humans as they do in animal studies. Developing vaccines often takes many years, sometimes decades, and this can cause major challenges when a disease like COVID-19 is spreading quickly around the world. Vaccines do not usually keep up with the speed of a pandemic, so researchers often combine phases 1 and 2 or 2 and 3 to speed up the development and testing processes. This helps scientists learn much more quickly whether a vaccine will continue being studied if it appears safe and effective or if it will be stopped because it has not shown to help prevent severe symptoms of an illness. When study phases are combined, the same safety protocols and standards are used as in traditional trials and all safety requirements must be met even at a more rapid testing speed.

Why is chlorine dioxide dangerous if taken for COVID-19?

Chlorine dioxide has not been verified by the medical and scientific community as a cure for COVID-19 or other diseases, and its use can be dangerous to human health. The U.S. Food & Drug Administration (FDA) has warned that risks of ingesting chlorine dioxide include: severe vomiting, severe diarrhea, low blood cell counts and low blood pressure due to dehydration, respiratory failure, changes to electrical activity in the heart that can lead to potentially fatal abnormal heart rhythms, and acute liver failure. The Government of Mexico and the Pan American Health Organization (Organización Panamericana de la Salud in Spanish) have also issued warnings to discourage the use of chlorine dioxide as a treatment for COVID-19. Chlorine dioxide is an oxidizing gas that can dissolve in water to form a solution. It is typically used as a disinfectant to sterilize medical and laboratory equipment and facilities or to treat water, rather than being used directly with humans, because it can pose significant health risks and has not been proven to treat diseases. The U.S. Centers for Disease Control and Prevention (CDC) says that while using chlorine dioxide as intended (not as a treatment for disease) is generally safe, direct exposure in larger quantities can cause “damage to the substances in blood that carry oxygen throughout the body.” If experiencing serious poisoning from consumption of a toxic substance like chlorine dioxide, people can seek assistance from a poison control center or seek medical care. Adverse reactions to COVID-19 products can also be reported by consumers and medical professionals to the U.S. FDA’s MedWatch Adverse Event Reporting Program.

What do we know so far about the COVID-19 vaccines during or before pregnancy and breastfeeding?

None of the three leading vaccine manufacturers (Pfizer, Moderna, and AstraZeneca) have reported data about the COVID-19 vaccine on knowingly pregnant or breastfeeding individuals. As a result, we have a limited understanding of how effective the three leading vaccines are for pregnant and breastfeeding people, and if there are specific risks.  Given this lack of data, some regulators and public health entities have not included pregnant people in their vaccine recommendations to the public with some specifically warning pregnant individuals against taking the vaccine. The WHO was one of these entities until Friday, January 29. Previously their guidance said that the vaccine was "currently not recommended" for pregnant women unless they are at high risk of exposure.  While their guidance, in practice, is still similar, recommending pregnant people with comorbidities or at high risk of exposure may be vaccinated in consult with doctors, they’ve directly noted that we “don’t have any specific reason to believe there will be specific risks that would outweigh the benefits of vaccination for pregnant women.” Until there is more data on COVID-19 vaccines and pregnancy, this trend of mixed guidance across different regulatory bodies and countries is likely to if and as vaccines continue to get approved.  Pregnant people who do receive a vaccine may be able to produce an immunity to the virus from the vaccine that can cross the placenta which would help keep the baby protected after birth. Regarding safety, however, when you receive an mRNA vaccine for COVID-19 you expel the mRNA particles from your body within days, so if pregnant it’s unlikely to cross the placenta and impact the baby. The process for collecting this data will involve analyzing the impacts of the vaccines on individuals who receive a vaccination and later discover that they’re pregnant. Countries are coordinating internal reporting and monitoring systems to record and track this information.  The clinical trials had some participants enrolled who didn’t know they were pregnant at the time of vaccination, but there were not enough of those cases to have enough data for definitive conclusions. For example, in Phase 2/3 of the Pfizer and BioNTech vaccine study, 23 pregnancies were reported through November 14, 2020. Twelve were in the vaccine group and 11 in the placebo group. Two adverse events occurred in pregnancies in the placebo group, including miscarriage. These initial data do not raise concern for lack of vaccine safety in pregnancy and breastfeeding, but more data is needed to safely recommend the use of this vaccine by pregnant and breastfeeding individuals. The U.S. FDA also recommended in June 2020 that the pharmaceutical companies developing COVID-19 vaccines first conduct developmental and reproductive toxicity (DART) studies of their vaccine before enrolling pregnant or breastfeeding people, or women not actively avoiding pregnancy, in their trials.  Pfizer and BioNTech have directly stated that they are conducting DART studies, which will provide us with more information on the safety and efficacy of their vaccine for pregnant and breastfeeding individuals. On December 13, the American College of Obstetricians and Gynecologists released a position paper advocating for the inclusion of pregnant women in vaccine rollouts and not waiting for further data collection. While the group advocates for obtaining informed consent from pregnant and lactating women receiving the vaccine, they feel the benefits of protection outweigh the risks. The U.S. Centers for Disease Control and Prevention (CDC), the American College of Obstetricians and Gynecologists (ACOG), and the Society for Maternal-Fetal Medicine support the use of new mRNA COVID-19 vaccines in pregnant and breastfeeding individuals when they become eligible for receiving the vaccine. As of January 26, 2021, the World Health Organization also supports pregnant and breastfeeding women receiving the Moderna mRNA vaccine if they choose. Before more data is available, it is best for pregnant and breastfeeding individuals to speak with their doctors about the best way to proceed. While it is unlikely that a doctor would recommend a pregnant or breastfeeding person get vaccinated before more data is available unless they were high risk, every risk profile is different and is worth discussing with a care provider.

What do we know about Eli Lilly's COVID-19 treatments?

The United States Food and Drug Administration (U.S. FDA) recently issued two Emergency Use Authorization (EUAs) for American pharmaceutical company Eli Lilly's most recent COVID-19 treatments. The first emergency use authorization was issued on November 19, 2020, for bamlanivimab, an antibody treatment. Bamlanivimab has been shown to reduce emergency room visits and hospitalizations in patients who receive the medication quickly after their diagnosis, according to early studies. No benefit has been shown in hospitalized patients with the virus. The treatment was developed with collaborators including Vancouver-based AbCellera and the U.S. National Institutes of Health. Bamlanivimab is a monoclonal antibody drug that mimics the immune system’s own antibodies that fight off harmful antigens such as viruses (like COVID-19). In this way, the medication might be able to help block the virus from entering and infecting healthy human cells. This drug should be dispensed as soon as possible after a person tests positive for the virus and within 10 days of developing systems. Bamlanivimab is authorized for people 12 years of age and older who weigh at least 40 kilograms (88 pounds) and who may be at risk for developing a severe case of COVID-19 infection or be hospitalized due to its impacts. Bamlanivimab was developed from the blood of a recovered patient who had developed antibodies to the virus. The data used to support this emergency use authorization was based on a phase two randomized clinical trial in 465 non-hospitalized adults with mild to moderate COVID-19 symptoms. Patients treated with bamlanivimab showed reduced viral load and rates of symptoms and hospitalization in comparison with those who did not receive the treatment. On November 19, 2020, (U.S. FDA) issued an EUA for the emergency use of Eli Lilly's drug baricitinib to be used in combination with another COVID-19 U.S. FDA-approved treatment, remdesivir, in adult patients who have been hospitalized with COVID-19. This treatment, which also goes by the brand name Olumiant, is normally used to treat rheumatoid arthritis and was developed in partnership with Incyte. In comparison to treating patients with remdesivir alone, baricitinib was shown to reduce time to recovery, when combined with the remdesivir. The safety of this investigational therapy is still being studied, but this medication combination was authorized for patients two years of age or older with suspected or confirmed cases of the virus who require supplemental oxygen, invasive mechanical ventilation, or extracorporeal membrane oxygenation (ECMO). The combination of drugs improved patients' median time to recovery from eight to seven days compared to remdesivir alone, a 12.5% improvement in the  1,000 patient study that began on May 8,2020, to assess the efficacy and safety of baricitinib plus remdesivir versus remdesivir in hospitalized patients with COVID-19. The proportion of patients who progressed to ventilation, or died by day 29, was 23% lower when given both drugs in comparison to remdesivir alone. By day 29, deaths among patients were also reduced by 35% for the combination treatment when compared to remdesivir by itself. The recommended dose for baricitinib in COVID-19 patients is 4 milligrams once daily for 14 days or until hospital discharge.

What does the AstraZeneca AZD1222 (ChAdOx1 nCoV-19) vaccine contain?

Some vaccines, including the Oxford Astra-Zeneca vaccine, are developed using something called a viral vector. A viral vector involves using a weakened and modified version of a virus, in order to teach the body how to activate an immune response against the actual virus. The University of Oxford-AstraZeneca vaccine, AZD122, uses an adenovirus vector as its technology. A spike glycoprotein (S) is found on the surface of the SARS-Cov-2 coronavirus virus through which the virus binds to receptors on human cells (ACE2 receptor) and gains access to insert itself and cause infection. Genetic material of this spike protein is added to ChAdOx1 virus vector so that the adenovirus can stimulate a response from a person's immune system when their body detects it in cells. When the vaccine is injected, it penetrates into the body and gives a blueprint (DNA) for how to defend itself against COVID-19. In this case, that means the cells start to produce club-shaped spike proteins found in coronaviruses, including COVID-19. These three-dimensional spike proteins are so similar to a normal COVID-19 infection that it causes inflammation and the creation of antibodies and T cells. Then, when a vaccinated person is eventually exposed to COVID-19, their body attacks the virus because it already recognizes how to respond to those spike proteins, and can fight against them to prevent infection. Essentially, the vaccine helps train human bodies to detect and eliminate a real COVID-19 infection by showing it mock spike proteins, before COVID-19 can cause any severe symptoms or a severe infection. Similar to all vaccination, it could cause side effects. Completed Phase 3 study results of this vaccine trial are yet to be published, but some early trial data showed that 60% of trial participants reported side effects from the injections. These symptoms included pain, feeling feverish, chills, muscle ache, headache, and malaise and many were treated with paracetamol. Injection-site pain and tenderness were the most common local adverse reactions within 48 hours of the injection and a significant number of side effect symptoms were reported in each age group over temporary symptoms of fever, sore throat, headaches or diarrhea. 

What checks and balances are in place to ensure vaccine manufacturers are producing safe products?

Standard vaccine development is a long process. Multiple studies on safety often take place over multiple years. Manufacturers use phased testing to determine an effective vaccine dose and to evaluate if the vaccine works, if it’s safe, if it has significant or serious side effects, and if immune systems respond well to the vaccine. To pursue regulatory authorization, a vaccine’s benefits must be shown to be greater than its risks, and vaccine safety and effectiveness are considered to be top priorities by regulatory agencies. Regulators around the world oversee vaccine development and testing at both national and international levels. In the European Union (EU), the European Medicines Agency (EMA) has a COVID-19 Task Force (COVID-ETF) that takes “quick and coordinated regulatory action on the development, authorization, and safety monitoring” for medicines and vaccines to treat and prevent COVID-19. In the US, the Food and Drug Administration (FDA) Center for Biologics Evaluation and Research (CBER) ensures that “rigorous scientific and regulatory processes are followed by those who pursue the development of vaccines.” Similar to the COVID-ETF in Europe, the FDA has also recruited experts from government agencies, academia, nonprofit organizations, pharmaceutical companies, and international partners to “develop a coordinated strategy for prioritizing and speeding development of the most promising treatments and vaccines.” To facilitate timely vaccine development during health crises, the US FDA sets clinical trial standards for scientific data on safety and efficacy, which manufacturers need to achieve in order to bring a vaccine to the US population. Once manufacturers meet those criteria, companies can pursue Emergency Use Authorization (EUA) approval, through which the manufacturer’s EUA submission is reviewed by FDA career scientists and physicians. So far, Moderna and Pfizer have both submitted data on their vaccines for FDA EUA approval.  While some COVID-19 vaccine manufacturers have requested emergency authorization with regulatory agencies around the world, it is important to note that if emergency authorization is approved, it is generally considered to be an emergency exception, with temporary permissions designed to accommodate the current COVID-19 public health crisis. Emergency authorization is not the same as formal licensing, which can take months. Unlicensed vaccines may be authorized by regulatory agencies and their lack of licensing does not mean that the vaccine has not been rigorously tested. Because of the nature of pandemic circumstances, for emergency authorizations, governmental agencies rather than manufacturers often assume responsibility for vaccine safety. In the US, for example, the Public Readiness and Emergency Preparedness Act (PREP Act) provides manufacturers, distributors, and others with liability immunity, as long as they have not participated in “willful misconduct.”  Regulatory oversight and monitoring will continue even once vaccines are approved for emergency use. In addition to testing by the vaccine manufacturers, government regulators regularly test vaccines for quality, and tweak manufacturing once they are released onto the market. Post-authorization, US vaccine safety monitoring is performed by the federal government (US FDA and the US Centers for Disease Control and Prevention [CDC]) and other agencies and organizations who are involved in healthcare delivery. Vaccine safety and monitoring systems are in place to quickly identify rare side effects that were not identified in clinical trials, and to detect possible vaccine safety problems.  Though no major safety concerns have been identified in the current vaccine trials, even when the current clinical trials are completed pharmaceutical companies, regulatory agencies, public health experts, researchers, and others will continue to evaluate safety, efficacy, effectiveness, and side effects in the years to come. The US FDA has stated that “efforts to speed vaccine development to address the ongoing COVID-19 pandemic have not sacrificed scientific standards, integrity of the vaccine review process, or safety.”

What can we expect when a population first begins getting vaccinated?

Once vaccine doses are distributed in the millions to a population, we can expect to see cases of COVID-19 dropping in those populations within a few months. Following a decrease in case numbers, we can expect decreases in hospitalization rates (the number of hospitalizations per 100,000 individuals), and then decreases in mortality rates (the number of deaths due to COVID-19 in a population). Importantly, we do not yet know how much we'll see these case numbers drop following the first vaccinations, because we don't yet know how effective the vaccines are outside clinical trials. The decrease could be minuscule or massive — and there's no way of knowing until the vaccines are distributed. The data we have on the most promising vaccines reflect vaccine efficacy, which is different than effectiveness and shows us how well a vaccine works to prevent a particular disease in a controlled, research environment. The data currently shows 95% efficacy for the Pfizer vaccine and 94.5% efficacy for the Moderna vaccine, with efficacy to be announced soon by AstraZeneca. We will not have data on vaccine effectiveness until a vaccine is made available to large populations outside of clinical trials. Given that U.K. Medicines & Healthcare products Regulatory Agency (MHRA) authorized the supply of Pfizer and BioNTech’s COVID-19 mRNA vaccine on December 2, we will likely have data on the Pfizer vaccine's effectiveness first. Once we have information on effectiveness, we’ll have a better sense of how the vaccines will impact metrics such as case numbers, test-positive rates, hospitalization rates, mortality rates, and level of disease severity. If vaccine distribution begins in early-mid-December (the Pfizer vaccine is set to begin being distributed in the U.K. on December 8), by mid-March to the highest risk individuals a population may begin to see declining case numbers. Depending on the rate at which a population is vaccinated, and particularly when distribution of the vaccine moves from highest risk individuals to the broader public, a December distribution start date to high-risk individuals followed quickly (within one month or so) by the general public could potentially vaccinate approximately 70% of that population by mid-late summer (within 6-8 months). This level of vaccination in a population would mean the population reaches herd immunity, triggering significant decreases in COVID-19 metrics such as case numbers, hospitalization rates, and mortality rates. However, if the general public in a population does not have access to vaccinations until later than this timeline (for example, April - June), herd immunity may not be reached until the fall or end of 2021 (6-8 months following). It is important to note that these types of timelines are estimates and based on an assumption that mass vaccination production and delivery is efficient. It also typically takes a few weeks for the body to build immunity after vaccination, so as a result, it is still possible for someone to contract COVID-19 just after they receive a vaccine, influencing case numbers. Case numbers, hospitalization rates, and mortality rates following vaccination in a country will depend on a variety of factors. First, different populations within countries suffer from COVID-19 morbidity and mortality differently. Black Americans, for example, have 2.6x higher case numbers, 4.7x higher hospitalization rates, and 2.1x higher mortality rates than white Americans. This will impact how much case numbers, hospitalizations and deaths fall in those populations after the first doses of vaccines get distributed to Americans. The distribution of vaccines is also not guaranteed to be equitable and there are varying degrees of willingness to even take a vaccine in some populations. Finally, some communities within a country may continue to practice recommended preventative guidelines (i.e. masks, social distancing) after the first rounds of vaccination, while others may not. Current projected distribution plans across the two most promising vaccines is for the vaccine to first go to emergency department clinicians, outpatient clinicians, testers at symptomatic sites, other high-risk health care workers, immunocompromised individuals, EMTs, and potentially essential federal employees, followed by the rest of the general population. However, in the case of Pfizer, they are permitting the regions, countries, and states, distributing the vaccines to determine the distribution plans. For instance, in the U.S., distribution plans are by state. In the United States, vaccines are currently intended to be allocated to all 50 states and eight territories, in addition to six major metropolitan areas. Pfizer, which has filed for emergency use authorization (EUA) in the U.S. and is the closest to potential approval, is prioritizing this approach over a plan that would prioritize the hardest-hit areas of the country, which they’ve said was decided due to the rapid wide spread of the virus. This plan will have impacts for the case rates and other metrics, as equal distribution will lead to different outcomes than targeted distribution. Other barriers to vaccine access include, among others, continual access to health care, particularly given that both the Pfizer and Moderna vaccine require two doses; cost (the vaccines are free but vaccination providers will be able to charge an administration fee); and potential supply chain challenges.

What is immunological memory to SARS-CoV-2 and can it last for more than six months after infection?

Immunological memory is the ability of your body's immune system to recognize a foreign virus or bacteria that the body has encountered before and start an immune response. A pre-print study was released on November 16, 2020 that assesses immunological memory to the virus SARS-CoV-2 for more than six months. This study analyzed 185 COVID-19 cases in the United States, including 41 cases after 6 months post-infection. Study authors found it promising that they could measure at least three components of immune memory in 96% of cases over 5 months after symptom onset. The authors believe this implies that durable immunity to help protect against reinfection of COVID-19 could be possible in most people. No significant difference was detected between males and females, and the authors reiterated that "the magnitude of the antibody response against SARS-CoV-2 is highly heterogenous between individuals." The authors acknowledge several study limitations, such as the relatively low number of severe COVID-19 cases in their study. Additionally, there is limited data on protective immunity against the virus SARS-CoV-2 and the disease COVID-19, so the authors cannot make direct conclusions about protective immunity from their study results at the time of publication because "mechanisms of protective immunity against SARS-CoV-2 or COVID-19 are not defined in humans." More research is underway to better understand long-term immunity against COVID-19.
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