There is no evidence that any of the approved COVID-19 vaccines cause herpes zoster, also known as shingles. While there have been cases of shingles occurring following COVID-19 vaccines, there is no evidence that these cases are directly caused by the vaccines. It likely would have occurred regardless. If anyone thinks they might have shingles, they should contact their doctor as soon as possible for treatment.

While several women are reporting temporary irregularities in their menstrual cycle, there is no scientific evidence available yet on the causal link between the COVID-19 vaccine and its effect on menstruation. Furthermore, there is no evidence that any of the COVID-19 vaccines could impact fertility or lead to a loss of fertility.   Getting vaccinated during one’s menstrual cycle does not pose any risks and the menstrual cycle has not been reported to have any effect on the vaccine efficacy. Vaccines should be taken as early as possible regardless of the timing of one’s menstrual cycle.

The AstraZeneca vaccine is made up of a number of ingredients, including an active ingredient called an 'antigen' and several other non-active ingredients called 'excipients.' These ingredients range from forms of salt that help preserve the vaccine to water that dilutes it into the right concentration.

Two of the most common ways to measure vaccines in a country are the number of vaccines administered per 100 people in a specified area, or the percentage of a population that has been vaccinated with one or two doses. There are many metrics which can be used, depending on the need.

CoronaVac is Sinovac Biotech's COVID-19 vaccine and uses a "killed" version of the COVID-19 virus. It cannot cause disease but can still trigger an immune response in its recipients. While the efficacy rates of the vaccine are mixed, CoronaVac appears to meet the World Health Organization's requirements for 50% minimal protection against severe symptomatic infections of the virus.

The immune system continues to fight against germs or invaders, like bacteria, viruses, and fungi, even during lockdown. It creates new immunity when it is exposed to invaders, but it does not weaken when it is not continuously challenged.

There is currently no evidence to suggest that COVID-19 vaccines are associated with Stevens-Johnson Syndrome (SJS). There have been a very small number of documented cases of SJS after other vaccines— such as influenza, smallpox, polio, hepatitis B, DTP (diphtheria, tetanus, and pertussis), and MMR (measles, mumps, and rubella), but these associations have not be proven to be causal in scientific studies. Like other vaccines, COVID-19 vaccines are being carefully monitored for any adverse reactions. The available evidence suggests that receiving the COVID-19 vaccine is much safer overall than COVID-19 itself.

There is currently no research to suggest that vaccinated people would be more likely than their unvaccinated counterparts to transmit variants of SARS-CoV-2. The U.S. Centers for Disease Control and Prevention (CDC) has stated that "a growing body of evidence suggests that fully vaccinated people are less likely to have asymptomatic infection and potentially less likely to transmit SARS-CoV-2 to others." The U.S. CDC also says there is evidence that the currently authorized COVID-19 vaccines provide at least some level of protection against variants of concern, including B.1.1.7 originally identified in the U.K. and B.1.351 originally identified in South Africa. The World Health Organization (WHO) recommends widespread vaccinations to potentially help reduce the transmission of current variants, as well as prevent the emergence of new variants. More research is being conducted to learn more.

Vaccines are broad in targeting the COVID-19 virus' early genetic codes. Current vaccines offer some protection against variants, but they will likely need to be adjusted to work against some newer variants.

VIPIT and CSVT are acronyms for rare blood clotting reactions that have occurred in people who have received AstraZeneca or Johnson & Johnson's COVID-19 vaccines. It is uncertain whether or not the vaccines caused these clotting issues, but researchers are currently working to determine whether or not there is a link.

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.

Most vaccines and medications cause side effects, but there is no evidence to support the claim that a second COVID-19 vaccine injection can lead to death. Some severe side effects like blood clots are possibly linked to the AstraZeneca and Johnson & Johnson vaccines in very rare cases, but there is not enough evidence to determine whether or not the vaccines are associated with this adverse effect. Not all vaccines have two doses. Of the vaccines that do, some are just now beginning to roll out, including those with little data. Though people have died after receiving vaccines, there have been no direct reports that have noted vaccines were the reason those people died.

Because the news about this vaccine is still early, there is still a lot we don't know. Remaining questions include when the vaccine might be available for everyone, if it will work in children younger than 12 (as they have been excluded from the early trials), if it will stop the virus from spreading in people who are infected but don't have any symptoms (asymptomatic), if it will prevent people from developing severe cases, and how long the vaccine might offer protection from the the virus.

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.

This vaccine requires an initial injection followed by a secondary shot called a “booster” to achieve its full level of protection. The clinical trial includes more than 43,000 volunteer participants, many of whom have already received two doses of the vaccine. In the interim analysis, there were 94 cases of COVID-19 in trial participants, and the study will continue until there have been 164 cases of COVID-19 among study volunteers.

Regeneron Pharmaceuticals, Inc., an American biotechnology company, recently received Emergency Use Authorization (EUA) for its COVID-19 antibody cocktail treatment of casirivimab and imdevimab by the United States. The treatment formerly known as REGN-COV2 is the first combination therapy to receive an EUA and can be used to treat mild to moderate cases of COVID-19 in recently diagnosed patients at high risk for severe cases of the virus and/or hospitalization. The treatment can also be used in pediatric patients at least 12 years of age and weighing at least 88.2 pounds or 40kg. It is an experimental drug that is designed to help the body prevent and fight off the virus. The drug is called a 'cocktail' because it mixes a combination of drugs so that it can be more effective and in this case, prevent the virus from becoming resistant to the treatment. This particular drug from Regeneron uses a combination of two "monoclonal antibodies," casirivimab and imdevimab. Antibodies are part of the immune system, and they help fight off infections and foreign invaders like COVID-19 by finding the virus, neutralizing it, and telling the rest of the immune system to begin launching its response. Monoclonal antibodies (which means 'one type of antibody') are antibodies created in a lab that can act as a replacement for the antibodies the body normally creates. These lab-made antibodies are different than the ones that the immune system creates naturally because they're uniquely designed to target and launch an attack against the specific the virus that causes COVID-19. Regeneron believes that individual antibody therapies are likely not strong enough to fight the virus that causes COVID-19, so they have combined two separate antibody treatments into one as a weapon to fight against the virus and prevent any drug resistance that might occur if they virus mutates and escapes the effects of the antibodies (called "viral escape"). Casirivimab and imdevimab are the two monoclonal antibodies in this cocktail which aims to help patients who were recently diagnosed with COVID-19 but have not yet launched their full immune system response, or who have a lot of the virus circulating in their blood. Additionally, this treatment is not authorized for use in people who are hospitalized or who need oxygen; just those with mild to moderate cases who recently tested positive for COVID-19. Regeneron also recently announced that people who received its antibody treatment had a lower number of medical visits for COVID-19 related causes in comparison to those who did not receive the treatment. Patients who received the antibody treatment made roughly 57% fewer visits to seek medical care than patients who received a placebo. In patients at high risk for serious complications from the virus (like those over 50 and people with cardiovascular or lung conditions), the reduction in visits was 72% lower than the group who did not receive the drug. Patients who were given the treatment also demonstrated lower levels of the virus in their blood and less severe symptoms than patients who did not receive the treatment. Though Regeneron's monoclonal antibody treatment has received an EUA, that authorization is only temporary so the cocktail therapy will continue to be evaluated in phase 2 and 3 clinical trials, according to the company. As of November 24, 2020, more than 7,000 people have participated in Regeneron's casirivimab and imdevimab clinical trials. The United States' government began distributing the treatment on November 24, 2020 starting with 30,000 treatment courses and expects to produce enough of the therapy to reach 80,000 patients by the end of November 2020. Regeneron's antibody cocktail is part of the United States' Operation Warp Speed and has received more than $500 million from the government to develop these treatments. This public–private partnership's goal is to create and distribution vaccines, therapies, and diagnostics for COVID-19 rapidly and safely and involves various government agencies and companies.

A “vaccine passport” is a proof that someone has been vaccinated against COVID-19. Currently, vaccine passports are being debated in the public health community for their many pros and cons. Vaccine passports are also being used, or planned to be used, in different ways across and within countries globally, which is a trend that is likely to continue.

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. 

There is no evidence to suggest that mRNA COVID-19 vaccines or non-mRNA COVID-19 vaccines would result in death, neuro-cognitive issues, debilitating/long-term inflammation, or infertility. 

In a study of hospital records of over 230,000 people who had been diagnosed with COVID-19, 33.62% of the patients developed a neurological or psychiatric diagnosis within 180 days of their viral infection. The most common diagnoses were anxiety and mood disorders but researchers are unsure of what causes these impacts in the brains of COVID-19 survivors.

The University of Oxford vaccine is being developed and produced by AstraZeneca plc, Inc. and is an adenovirus vaccine (ChAdOx1/AZD1222) currently in Phase 2 and 3 trials in the United Kingdom and India, and in Phase 3 trials in Brazil, South Africa, and the United States. As of December 30, 2020, the vaccine has been authorized for emergency use in adults over 18 years of age in the United Kingdom. Here's a breakdown of everything you need to know so far about this vaccine's development.

Most people get infected with a coronavirus at some point in their lives, meaning that it is highly likely that coronaviruses will continue impacting us. The likelihood of another novel coronavirus emerging is less clear, but science suggests that the risks are high.

Women may experience more significant side effects to COVID-19 vaccines, but more data is needed to know for sure.

The COVID-19 arm rash is a side effect from the vaccine that can cause an itchy or painful rash on the arms of people who have received a vaccine. The rash is harmless and tends to go away within a few days but can be treated with histamine medication or some pain medication if symptoms persist.

AstraZeneca worked in partnership with the University of Oxford to create their vaccine for COVID-19. This vaccine has been approved for emergency use authorization in dozens of countries around the world and uses a formula called a 'viral vector' where a weakened common cold virus (adenovirus) is used to deliver instructions to the body for how to fight COVID-19.

Glandular fever or Infectious Mononucleosis is a viral infection generally caused by Epstein-Barr virus (EBV). It can be transmitted by close contact with an infected individual. There have been recent news articles that patients with long term symptoms of COVID-19 may have reactivated EBV in their bodies. Some have reported ‘reactivated’ EBV in their blood tests, leading scientists to look at the relation between COVID-19 and EBV, which have similar symptoms. Research is underway to understand more, and as more information becomes available, scientists will be able to find conclusive evidence.

Early data on whether the COVID-19 vaccines are able to reduce transmission look positive, but more research is needed to get to a conclusion. A person who is vaccinated for COVID-19 may still be able to transmit the virus.

A recent string of blood clotting events in people who had received the AstraZeneca vaccine caused several European nations to halt their use of the shots while they investigated. The European Medicines Agency said that the benefit of the vaccine outweighs the risks and though there have been no direct links between these blood clotting events and the vaccine itself, they will continue to research.

The U.S. C.D.C. recommends that fully protected people should continue to wear masks in public, stay six feet apart and avoid crowded and poorly ventilated spaces. Fully vaccinated people can gather indoors with other fully vaccinated people without wearing masks. Fully vaccinated people can gather indoors with one household of unvaccinated people if they are at a low-risk of severe COVID-19 illness. After exposure to COVID-19 infected person, quarantine and testing are not needed unless symptomatic. However, those living in group settings need to quarantine and get tested after a known COVID-19 exposure. The CDC recommends avoiding medium or large gatherings, delay domestic and international travel, or follow CDC requirements and recommendations if you must travel.

You do not need to have any kind of COVID-19 test before you are vaccinated. It is recommended that you do not receive a vaccine until you are free from a prior COVID-19 infection for 90 days.

Major Brazilian cities are recording new daily highs in COVID-19 deaths as of March 2021, sparking concerns about the risks of a variant known as P.1 that was first identified in Brazil. P.1 is still being studied, but preliminary research suggests it could be associated with an increase in transmissibility and/or reinfection.

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.

Blue surgical masks are safe to wear and are made with non-woven fabric.

Long-haul COVID is the continued experience of symptoms caused by COVID-19 for several weeks or months after the initial infection began. Some of the reported persistent symptoms include fatigue, headaches, shortness of breath, anxiety, and depression, palpitations, chest pains, joint or muscle pain and weakness, loss of smell, cough, low fever, headache, and cognitive dysfunction (brain fog, not being able to think straight or focus). More serious complications, although less common, include damage to the heart, lungs, kidney, and gut due to blood clots or weakened blood vessels.

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. 

No, there is no combination of food or drinks that can treat, prevent, or cure COVID-19. However, eating a varied and balanced diet including fruits and vegetables does help to support the immune system in general.

A human challenge trial (HCT) is a study that deliberately infects volunteers with a virus after they've been given a vaccine, in order to see if the vaccine is effective. Clinical trials usually allow participants to be exposed to COVID-19 in their day-to-day lives, but HCTs intentionally infect volunteers in order to learn about the virus, immune responses, medications, and treatments.

As of February 19, 2021, the World Health Organization (WHO) has approved the Pfizer/BioNTech COVID-19 vaccine (December 31, 2020) and two versions of the AstraZeneca/Oxford COVID-19 vaccine (February 15, 2021) under its Emergency Use Listing (EUL).  The Sinopharm inactivated virus COVID-19 vaccine is being developed and produced in conjunction with the China National Biotec Group and the Beijing Institute of Biological Products. The vaccine is in phase three trials in Argentina, Jordan, Egypt, Bahrain, and United Arab Emirates. Sinopharm is pursuing emergency approval and, according to WHO records dated January 20, 2021, Sinopharm submitted study data and safety, efficacy, and quality information to the WHO in December 2020. The assessment is ongoing and a decision could be made as early as March. Another Sinopharm COVID-19 vaccine is being tested in conjunction with the China National Biotec Group and the Wuhan Institute of Biological Products. This vaccine is currently in phase three trials in Jordan, Egypt, Bahrain, Morocco, Peru, and United Arab Emirates. According to WHO documentation dated January 20, 2021, there has not been a pre-submission meeting or further pursuit of emergency approval for this vaccine. 

As of March 30, 2021, there is not enough evidence to suggest COVID-19 vaccines can cause thrombosis but research is still ongoing. Most national drug agencies have noted the benefit of vaccines is greater than the risks they may pose.

The recent variant of COVID-19 called B.1.1.7, first found in the United Kingdom in 2020, has caused many to question whether or not current vaccines will still be effective in preventing the virus from causing a severe infection. The U.S. National Institute of Allergy and Infectious Diseases believe that the Pfizer and Moderna vaccines will provide protection against the variant first found in the UK. If not, mRNA vaccines can be altered in a laboratory by changing the sequence of the genetic code of the vaccine so it matches that of the new variant. Experts at AstraZeneca also believe that a vaccine they created with Oxford University will be effective against this new variant. It's unknown how the remaining COVID-19 vaccines, which have been approved for use in far fewer countries than the mRNA or AstraZeneca vaccines, will protect against vaccine variants. Many scientists remain optimistic that these vaccines will offer some protection against genetic changes.

According to the World Health Organization (WHO), the virus that causes COVID-19 is primarily spread through respiratory droplets (little spit droplets that fly out when a person sneezes, coughs or talks). Respiratory droplets can infect other people who are nearby, or indirectly infect others when they touch a surface contaminated with infected droplets. After an open letter by scientists in July 2020, the WHO now acknowledges the possibility of airborne transmission, which is caused by smaller and lighter 'droplet nuclei' (residuals of respiratory droplets from infected people) that can remain in the air for longer periods of time and remain infectious over long distances. Experts are looking at previous data from China to see whether the virus may spread through the air or through vents via airborne transmission. While a few lab-based studies have found that the virus can be present in the air for up to three hours, these studies did not assess if the virus is viable to infect anyone else. Recently, a research study published in Nature found viral contamination in air samples from patients isolated at a medical center, which supports the use of airborne isolation precautions in caring for COVID-19 cases. A few studies have also looked into how airborne transmission may have played a role in certain outbreaks, such as the one in the Diamond Princess cruise ship. One of these studies in pre-print found that it was likely that a combination of both close-range (respiratory droplet) transmission and long-range (airborne) transmission contributed similarly to disease progression aboard the ship. Thus far, the WHO still claims that evidence points to close person-to-person respiratory droplet transmission as the primary mode of COVID-19 transmission. However, experts warn that there is significant reason to believe airborne transmission is happening. The U.S. Centers for Disease Control and Prevention (CDC) now provides infection control recommendations for airborne transmission as well as respiratory droplet transmission. Definitive studies may take a long time to alter the body of evidence in the coming weeks and months, but proactive prevention measures such as universal use of masks (the U.S. CDC recommends wearing a cloth mask over a surgical mask for increased protection) could save lives in the meantime.

People with asthma should wear face masks. The U.S. Centers for Disease Control and Prevention (U.S. CDC) note that people with moderate to severe asthma might have an increased risk of severe case of COVID-19. Therefore, wearing a mask is an important way to prevent the spread of the virus. Studies also show that wearing a mask does not reduce oxygen levels and should not make breathing more difficult. The World Health Organization (WHO) recommends the use of face masks in public and when social distancing is not possible, and it is safe for people with asthma to wear a mask for as long as needed. People who feel it is difficult to breathe adequately with a mask ca, for example, try to limit the length of their outings requiring mask use. However, every patient is different and if you have been diagnosed with asthma, have a severe case, have difficulty breathing normally, or have difficulty breathing with a mask, you should speak with your doctor about options for protecting yourself and others from COVID-19. As of February 2021, the U.S. CDC recommends wearing a cloth mask over a surgical mask for increased protection.

Yes. Wearing a face mask helps prevent the spread of COVID-19 in two ways: It protects the person wearing a mask from being exposed to the virus and protects the people around them from being exposed to the virus. The World Health Organization recommends wearing a face mask as part of a comprehensive strategy to prevent the spread of the virus.

Scientists are working to better understand the new variants (or versions) of the COVID-19 virus, how they spread, if vaccines will be effective, if the new variants are detectable by viral tests, and whether the variants cause mild or severe disease. Information about new variants of COVID-19 is changing quickly. According to the US Centers for Disease Control and Prevention, there is no evidence that the new COVID-19 variants cause more severe illness or increased risk of death. However, there is some evidence that suggests that one mutation (D614G) may spread more quickly than other variants. Viruses constantly change as they reproduce in order to keep spreading into more cells. These changes are called "viral mutations." Mutations create a new, updated version of the virus, which we call a "strain" or "variant" (though other similar words include "lineage" and "mutant"). These variants may have different properties than previous versions of the virus and may allow the virus to infect more people or may cause more severe illness. Many variants of COVID-19 have been documented globally, and scientists are continuing to monitor the virus as it changes and spreads around the world. To prevent the spread of COVID-19, international health agencies and the public health community continue to encourage the everyone to wear face masks (the U.S. Centers for Disease Control and Prevention now recommend wearing a cloth mask over a surgical mask or individual KN95/N95 masks), practice social distancing (maintaining 6 feet/2 meters physical distance), avoid crowds especially in indoor areas, and practice frequent hand washing with soap and warm water. 

Imposing restrictions at a hyper-local level, such as by postal code or zip code, can work to contain COVID-19, but is not without challenges and comes with a set of both pros and cons. The pros come into effect if individuals who are residents of that zip code or neighborhood a) follow the restrictions imposed and do not travel outside their neighborhood, especially at a mass level. The cons come into effect if individuals who are residents of that zip code or neighborhood either do not follow restrictions imposed, or travel outside their neighborhood, especially at a mass level. As a result, it’s crucial to communicate with residents so that they understand the expectations and what is at risk if local measures aren’t followed. To help ensure that they are followed, local public health officials and leaders must share information with residents on how to access the resources that they need hyper-locally, both for healthcare and otherwise, so that individuals are not pushed to seek resources outside of their affected area, and in turn potentially increasing positive rates in other neighborhoods, worsening the problem overall.  Of note is that hyperlocal surveillance of COVID-19 is also useful for tracking and ultimately controlling the spread of the virus, as the more local the data is, the more granular it is likely to be and the less gaps it is likely to have.

We should all be wearing masks to prevent the spread of COVID-19 to others and prevent infection in ourselves. The virus is spread primarily through respiratory droplets and aerosolized transmission when people speak, cough, sneeze, or sing so wearing a mask can prevent people from releasing viral particles from their mouth and nose into the air.

If a pregnant person becomes infected with COVID-19 there is a higher chance they will require hospitalization and suffer more serious symptoms of the disease. In early November 2020, the U.S. Centers for Disease Control and Prevention (U.S. CDC) released a report on 400,000 women between the ages of 15 and 44 with symptomatic COVID-19 which found that admission to the intensive care unit (ICU), invasive ventilation, extracorporeal membrane oxygenation, and death were more likely in pregnant women than in non-pregnant women. The report includes that increased risk for admission to the ICU was "particularly notable" among Asian and Native Hawaiian/Pacific Islander pregnant women, and that both disproportionate risk for SARS-CoV-2 infection and higher risk for death was observed for pregnant Hispanic women. Highlighting the racial/ethic disparities, the report states that "regardless of pregnancy status, non-Hispanic Black women experienced a disproportionate number of deaths." This report adds to the current knowledge around increased risks related to COVID-19 for pregnant women, particularly pregnant women of color, and suggests that pregnant women should be counseled about increased risks of severe illness or death related to COVID-19 as well as measures to prevent infection in their families. Preterm birth has also been associated with COVID-19, according to another report released by the U.S. CDC in early November 2020. The U.S. CDC encourages people to take preventive measures while pregnant and to seek prenatal care throughout pregnancy. If a person is infectious during labor, it is possible for them to spread the virus to the baby. Outside of the U.S., the World Health Organization (WHO) has reported that emerging international research suggests pregnant women with COVID-19 are more likely to need intensive care if severely ill, and more likely to give birth prematurely. The latest findings also suggest that pregnant women with COVID-19 who have pre-existing medical conditions, who are older, or who are overweight are more likely to suffer severe health complications due to COVID-19.

There is increasing evidence that COVID-19 can spread through airborne transmission, which is when a person infected with COVID-19 releases tiny droplets of fluid into the air called 'droplet nuclei' by coughing, sneezing, talking, or during some medical appointments and procedures. Droplet nuclei are very light, relatively dry, and microscopic in size so they can remain suspended in the air like a mist, which is why airborne transmission is also called 'aerosol transmission.' This is different from the main theory that the virus spreads through bigger respiratory droplets that are heavier, fall to the ground relatively quickly, and do not remain suspended in the air or spread through the air.  While researchers are continuing to study aerosol transmission of COVID-19, the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC) acknowledged evidence of airborne transmission in poorly ventilated spaces. Enclosed spaces have been found—through scientific studies as well as case studies—to contain enough virus to cause infections in people more than six feet apart, or who passed through a space soon after an infectious person left the room.  One study conducted at the University of Nebraska Medical Center collected air and surface samples from the rooms of isolated individuals to examine viral shedding, and found evidence of the novel coronavirus in the air from isolated individuals who had COVID-19 (including at a distance from the infected individual and outside of their room in the hallway). As a second piece of evidence, a study from Singapore found that COVID-19 virus aerosol particles were found in two "airborne infection isolation rooms" in hospital wards, despite these rooms being intentionally well ventilated to prevent transmission. In a study that modeled the transmission of COVID-19 during the outbreak on the Diamond Princess cruise ship in early 2020, researchers found that aerosol inhalation of the virus was likely the dominant contributor to COVID-19 transmission among passengers.  Another study outlined the case of the Skagit Valley Chorale rehearsal in Mount Vernon, Washington, which took place in early March 2020 and resulted in 45 out of 60 members of the chorus testing positive for or showing COVID-19 symptoms after a 2 ½ hour indoor practice session. No attendees reported physical contact between members, as person-to-person contact and touching of surfaces was intentionally limited. No one was located within 3 meters in front of the index COVID-19 case, where larger respiratory droplets from that individual would have likely landed. The authors concluded that inhalation of infectious respiratory aerosol from shared air was the leading mode of transmission and that dense occupancy, long duration, loud vocalization, and poor ventilation increased risk.  Another case study was reported in China in early February when a who passed by the door of a symptomatic patient several times person contracted COVID-19. Finally, one China-based study compared risks of COVID-19 outbreak among 126 passengers taking two buses on a 100-minute round trip. Compared to individuals in the non-exposed bus (Bus #1), those in the exposed bus (Bus #2) were 41.5 times more likely to be infected, suggesting airborne transmission of the virus, particularly given the closed environment with air recirculation and lack of contact between passengers.  These studies, and others like them, highlight the importance of combining proper ventilation with cloth masks and social distancing to prevent transmission of the virus. The U.S. CDC's most recent guidelines suggest wearing a cloth mask over a surgical mask or an individual KN95/N95 mask as these methods can offer the most protection from the virus, but any mask offers substantially more protection than not wearing one. Studies such as these are particularly important as it would not be ethical to run a randomized control trial (RCT) to test different transmission modes in infecting individuals, and given that it’s difficult to specifically pinpoint in a study how someone was infected without a highly controlled environment, such as that of an RCT. Public health experts have repeatedly warned that airborne transmission is most likely contributing to transmission, especially in indoor spaces, and recommendations should incorporate the need for sufficient ventilation, high-efficiency filtration, and limiting crowded spaces, in addition to universal adoption of masks, social distancing, and frequent handwashing with soap and water.

The Emergency Use Authorization (EUA) is a different standard than FDA Approval. FDA Approval from the US Food and Drug Agency is an independent, scientifically reviewed approval for medical products, drugs and vaccines. Based on substantial clinical data and evidence, the product is deemed safe, effective and able to be produced within federal quality standards. The process for an Emergency Use Authorization (EUA) is different than an FDA approval. EUA is a mechanism used by the FDA to facilitate making products available quickly during a public health emergencies (like the current COVID-19 pandemic), when there is no other adequate and approved medical product available. Emergency Use Authorization allows for the use of medical products that are not yet formally approved, so that in the midst of an emergency, the products can be used to diagnose, treat or prevent serious illness or conditions. In order to give the authorization, FDA evaluates the potential risks and benefits of the products based on the scientific evidence that is available at that time. EUAs end when the emergency declaration ends. They can also be revised or revoked as more data is made available.

Wearing a face mask is both safe and recommended to slow the spread of COVID-19. The United States Centers for Disease Control recommends widespread use of cloth face coverings over surgical masks to prevent spread from people who might have the virus that causes COVID-19 without realizing it. While N95 masks are in short supply and should be reserved for healthcare workers, cloth face coverings should always be worn when interacting with other people in close proximity (including but not limited to grocery shopping, ordering food at a restaurant, interacting with people within 6 feet in outdoor spaces). You should clean your hands before touching the mask, make sure the mask covers your nose and mouth, and ensure the mask fits tightly on your face without leaving exposed spaces. Additionally, you should avoid touching the front of the mask, avoid taking the mask off when talking to other people; only remove the mask by touching the straps; wash your hands after removing the mask; wash the mask in soap and detergent with hot water at least once a day; and avoid sharing masks with others or leaving used masks around other people. While mask wearing is recognized as safe and is advised by the World Health Organization and other leading health advisory groups, there are cases where masks should not be used. For instance, masks are not safe for children under 2 years of age, people who have trouble breathing in general, or individuals who are unconscious or who would be unable to remove the mask without help.  Several cities and states, such as New Orleans and Washington, have mandated the use of face masks to slow the spread of the virus. However, masks alone are not enough. In addition to wearing a mask to help stop the spread of the virus, public health experts encourage social distancing (staying at least 6 feet (2 meters) away from others) as well as frequent and thorough hand washing.

The SARS-CoV-2 virus that causes COVID-19 mostly spreads from person to person. The virus is transmitted via tiny droplets from infected people when they cough, sneeze, talk or sing. An individual who might be in close proximity to an infected person can then inhale the virus and get infected themselves. The virus can even spread through people who do not show any symptoms, but are infected with COVID-19. It is not only important to stay home and maintain social distance if you have symptoms, but it is necessary to maintain physical distance even when one may not have symptoms, in order to keep oneself and others around safe from getting infected through any asymptomatic or presymptomatic cases. U.S. CDC and WHO, therefore, recommend that social distancing should be maintained indoors and outdoors between people who are not from the same household. Social distancing, along with other preventative measures, like hand washing with soap and water for at least 20 seconds and using face masks (the U.S. CDC now recommends wearing a cloth mask over a surgical mask), can reduce the spread of COVID-19 to a great extent.

There is no scientific evidence to suggest that taking vitamin C will prevent against or cure COVID-19. Though studies are underway, there is not enough scientific evidence to recommend taking vitamin C as part of a treatment for COVID-19 unless it is part of a study protocol.

The claim that the prolonged use of face masks can cause oxygen deficiency, carbon dioxide intoxication, dizziness, or other health challenges is not grounded in science. Science shows that the risks associated with wearing masks are generally minimal, and the benefits plenty. Even if a person is wearing an airtight medical grade mask, like an N95 or FFP2 mask, the risks of lethargy, headache, and dizziness are low, even after wearing one for several hours. For an average healthy person wearing a cloth or surgical mask, there is even less risk of these symptoms occurring, because they still allow oxygen to flow out of the mouth and nose freely. While it might feel like breathing is more difficult in a mask and you are not getting enough air, that is likely a response to stress or anxiety from wearing the mask and can usually be helped by focusing on normal breathing patterns. Shallow breathing, hyperventilation, and breath holding can cause increases in carbon dioxide which leads to headaches and nausea. These symptoms are generally not caused by the use of masks.

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.

There is no evidence to suggest that cloth masks can cause suffocation though they may raise your body temperature.

The majority of cancer survivors, who have been cancer-free for at least five years, are likely to have normal immune system functions and are not at an increased risk for COVID-19. However, every body is different so every cancer survivor should speak with a doctor who knows their full medical history and can discuss their personal risks with them. For some cancer survivors, their previous treatments might impact their risk of getting COVID-19 or having a severe form of the disease, as these treatments can have long term effects on the immune system and cause the survivor to have preexisting conditions that may put them at a higher risk for viral infection. For example, patients who have undergone a bone marrow transplant (also known as a 'stem cell transplant') might not regain a completely functional immune system as the transplant depletes their white blood cell system (which the body then replaces). Some patients who have undergone bone marrow transplants are no longer immune to illnesses they had become immune to before the procedure. These patients can be at risk for a number of infections, including COVID-19, but the longer it has been since treatment, the more time your body's immune system has had to improve. Despite not having a higher risk of becoming infected with the virus than the general population, it should be noted that cancer survivors do have a higher risk of complications if they become infected with COVID-19. This group is also more likely to be hospitalized if they are infected, compared to people who have never had cancer before. To protect themselves from the virus, just like the general population, cancer survivors should use protective measures like wearing cloth masks over surgical masks, maintaining at least six feet of distance, staying home when they can, and washing hands thoroughly and often.

The virus that causes COVID-19 can infect people of all ages. Although older people are known to be more likely to have severe side effects of the virus, that does not mean young people are not at risk of getting sick, or even dying, from COVID-19. In addition, young people, including children, may spread COVID-19 to relatives and contacts who may be older or have other risk factors. Young people with underlying health conditions are at higher risk of severe COVID-19, but young people with no prior health issues have also been impacted by the disease. Less severe COVID-19 can lead to lingering health impacts that have prevented some young people from going to school, working and resuming other normal activities for months. As of December 3, 2020, over 1.4 million US children have tested positive for COVID-19. In total, children have accounted for 12% of US COVID-19 cases though there was a 23% increase in child COVID-19 cases recorded between November 19 and December 3, 2020. In spite of the recent increase, the incidence of severe illness in children remains uncommon, though it is possible. In a study of 85,000 COVID-19 cases in India, almost 600,000 of their contacts showed that children of all ages can become infected with COVID-19 and spread it to others. More than 5,300 school-aged children in the study had infected 2,508 contacts. More evidence is emerging on how some young people develop severe symptoms and complications related to COVID-19, and are contributing to the widespread transmission of the virus. Young people should take preventive measures, including wearing face masks (recent guidance from the U.S. Centers for Disease Control and Prevention suggests wearing a cloth mask over a surgical mask or a high quality respirators), practicing social distancing (6 feet/2 meters), avoidance of crowds, and frequent hand-washing, to prevent the spread of COVID-19. These measures are suggested for their own protection as well as for preventing the spread of COVID-19 to others.

COVID-19 can be spread in all climates and seasons. According to an August publication in the journal Nature, 'No human-settled area in the world is protected from COVID-19 transmission by virtue of weather, at any point in the year.' Studies that have explored the impact of temperature or weather on COVID-19 spread have shown mixed results. Some have been positive, some negative, and others neutral. Researchers have concluded that there are many factors that likely play a much larger role in the spread of the virus than the weather, including population density, human mobility, social distancing policies and practices, testing, public health facilities, and more. While more studies are needed, warmer weather does not appear to reduce the spread of COVID-19, and it does not impact how the virus spreads from person to person. Routine hand-washing, social distancing practices, avoidance of crowds, wearing face masks (the U.S. Centers for Disease Control and Prevention recommend wearing a cloth mask over a surgical mask), and surface cleaning should be used to prevent the spread of COVID-19 between people and via indirect (non-contact) transmission.

According to the World Health Organization (WHO), wearing masks is part of an overall strategy to suppress the transmission of COVID-19, along with maintaining at least 2 meters (6 feet) distance and frequently washing your hands. A recent study conducted by the U.S. Centers for Disease Control and Prevention found that by wearing two masks, people's protection against the virus in the air dramatically increased. The study demonstrated that wearing any kind of mask provides significantly more protection against infectious COVID-19 aerosols than not wearing a mask. When dummies wearing two masks - like cloth face masks over surgical masks - were exposed to infectious aerosols, their level of protection was roughly 92%. The CDC 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. There are generally two kinds of face masks that are available: medical masks and non-medical (or fabric) masks. Medical masks can protect people from getting infected as well as prevent people who are infected from spreading disease to others. Therefore, WHO recommends medical masks to be worn by health workers, care givers of patients infected with COVID-19, anyone who has mild symptoms of COVID-19, people with other health conditions which make them more susceptible to COVID-19, as well as people who are 60 years or older because they have a higher risk of getting infected with COVID-19. The WHO advises that non-medical masks should be worn in areas where there is high transmission of COVID-19, crowded places where at least 2 meters (6 feet) physical distancing is not possible, on public transport, in shops and other closed areas. COVID-19 can spread from people without symptoms, as they may not know that they are infected but are equally capable of spreading the virus. Hence, masks should be worn in public settings. The U.S. CDC warns that masks with exhalation valves or vents may not help prevent the spread of COVID-19 from the person wearing such a mask to others, therefore these masks should not be used for that purpose. The U.S. CDC also does not recommend face shields as substitutes for masks because of the large gaps below and alongside the face. Ideally, face shields should be used in combination with face masks. Wearing a face mask protects others from you when you cough, sneeze, talk, or just breathe, particularly indoors or when standing close to someone. Face masks also protect the wearer by preventing people from touching their mouth and nose, as well as reducing the amount of virus inhaled from other people nearby and reducing the risks of severe illness. In addition to social distancing measures (maintaining 6 feet or 2 meters between people), face masks are recommended to prevent the spread of COVID-19, even in hot climates. There is no evidence that surgical masks or cloth masks lower oxygen levels at all. It is important to use a mask that allows you to breathe comfortably while talking and walking and that fits well on your face. For safety, there are exceptions to wearing masks for children under the age of 2, for people with certain medical conditions or who have trouble breathing, and for anyone who is unconscious or unable to remove the mask without assistance. Mask wearing is a fundamental element of pandemic response for respiratory illnesses because masks act as a physical barrier from the release of infectious respiratory droplets that may come from your mouth or nose when you speak, sing, sneeze or cough.

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.

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>

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.

Pfizer-BioNTEch and Moderna have started working on booster doses for their vaccines because of concerns that current versions will be less effective against new, possibly more contagious, COVID-19 variants.  Pfizer-BioNTEch and Moderna vaccines are made using mRNA, which is like a genetic software code that can be updated relatively easily and quickly. Tweaking the vaccine can be done in a couple of days, but updated vaccine trials might require more time. The FDA's testing process and policy for the new booster shots is not yet known, but is expected to be publicized soon. Some experts suggest that the end result may look similar to the FDA's process for the flu vaccine, which changes every year but does not go through full-scale clinical trial phases every time an adjustment is made. Viral mutations are a common phenomenon in infectious diseases. COVID-19 vaccine manufacturers report that their vaccines work against the mutations identified in the U.K. and South Africa, but their laboratory studies suggest that the vaccines are less effective against the variant identified in South Africa.

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.

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.

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.

The Covaxin vaccine is a vaccine developed by Bharat Biotech and uses an inactivated virus approach to help the body build an immune response against COVID-19. Inactivated viral vaccines have been used for over 100 years, including for polio, rabies and hepatitis A. In order to grow cells in laboratory settings for vaccine research, serum from calf or fetal blood is sometimes used. It helps cells grow and replicate so they can be studied. Covaxin has been reported to use calf serum as a building block in its vaccine development, according to journalists. Bharat Biotech—the maker of Covaxin—has yet to comment on whether the presence of calf serum is used in the vaccine itself, or just in the vaccine's development process According to Bharat BioTech, the Covaxin vaccine is made up of 6µg of whole-virion inactivated SARS-CoV-2 antigen (Strain: NIV-2020-770), and the other inactive ingredients such as aluminum hydroxide gel, TLR 7/8 agonist (imidazoquinolinone, TM 2-phenoxyethanol, and phosphate buffer saline.

Eating more acidic or alkaline foods is not related to an increased or decreased risk of COVID-19 infection. Widely circulated social media posts falsely suggest that the pH of COVID-19 ranges from 5.5 to 8.5. Often these posts advise readers to eat alkaline foods (specifically fruits and vegetables) with a pH of more than 8.5 to prevent COVID-19.  Viruses themselves do not have pH levels, because they are not water-based solutions.In chemistry, pH (power of hydrogen, or potential for hydrogen) is a scale used for water-based solutions to indicate if they are acidic (pH below 7, with a lower pH indicating a stronger acid), neutral (pH around 7), or basic (pH above 7, with a higher indicating a stronger base). Since viruses are not water-based, the pH scale does not apply to the novel coronavirus SARS-CoV-2, the disease that causes COVID-19.While some illnesses or medications may cause blood pH levels to increase or decrease in our bodies, foods eaten as part of a regular diet do not have a significant impact on blood pH. Saliva and urine pH may change in response to diet, but these changes are variable from person to person and **will not prevent or cure COVID-19**. Many claims about alkaline foods preventing COVID-19 refer to a 1991 paper in which another type of coronavirus, the coronavirus mouse hepatitis type 4 (MHV4), was studied in mouse or rat cells in a solution with a pH of 5.5 to 8.5. Mice and rats are not the same as humans, and this study was not conducted in humans or on human cells. In addition, MHV4 is not the same as the SARS-Cov-2 virus that causes COVID-19, and this study was performed well before the SARS-Cov-2 was discovered in 2019. Eating a well-balanced diet including a variety of fruits and vegetables can help support immune function which may help to prevent illness in general, but there is not enough evidence to suggest that a well-balanced diet would be effective in preventing or treating COVID-19. 

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.

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.

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."

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.

COVID-19 mRNA vaccines help our bodies create spike proteins, which generate an immune response to fight the COVID-19. There is no evidence that mRNA vaccines create other proteins, and there is no evidence that mRNA vaccines cause autoimmune diseases. 

COVAX is the largest international partnership for COVID-19 vaccine development and equitable distribution in the world. As many countries may struggle to afford the amount of vaccine dosages necessary to treat their populations, COVAX helps guarantee a share of doses for each eligible participant country (also called 'economy') and will ensure countries are not pushed to the back of the line or unable to receive the most effective vaccines according to their financial abilities.  COVAX secures agreements with numerous vaccine producers directly so that the risks of paying for on only one or two vaccine candidates are minimized as the organization is working with roughly 10 companies. This means that if a vaccine is not shown to be effective or cannot get appropriate authorization in individual countries, there are still other vaccines in the COVAX portfolio that might meet these standards. As of December 8, 2020, 189 countries are participating in the COVAX Facility program for fair and equitable distribution of an eventual licensed vaccine, assuring that each participating country would receive a guaranteed share of doses to vaccinate the most vulnerable 20% of its population by the end of 2021.

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.

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.

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.

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.

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.

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.

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.

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.

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.

According to the US National Institutes of Health, "there are insufficient data to recommend either for or against the use of vitamin D for the prevention or treatment of COVID-19." Researchers are now working on several studies to determine if Vitamin D can be effective in preventing or treating COVID-19. Multiple observational studies have shown an association between vitamin D deficiency and higher numbers of COVID-19 cases and deaths. While current evidence does suggest that vitamin D deficiency may be a risk factor for COVID-19, there have not been studies to evaluate whether vitamin D supplementation may help prevent COVID-19. Further studies are also needed to better understand what level of deficiency carries COVID-19 risk. A pre-print study from November 2020, found that vitamin D supplementation did not benefit hospitalized patients with severe COVID-19. Researchers noted that vitamin D levels did increase, but hospital length of stay, mortality (death), admission to the intensive care (ICU), and the need for mechanical ventilation (ventilator support for breathing) did not significantly differ between the experimental group who received vitamin D and the placebo group (who did not receive vitamin D). Studies to explore the possible benefit of vitamin D supplementation in prevention and treatment of COVID-19 are ongoing.

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. 

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.

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. 

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.

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.

The human body has lots of different types of cells, and they serve many different purposes. MRNA vaccines like Pfizer and Moderna's vaccines interact with multiple types of cells once they enter the human body, including immune cells, which are the cells that launch a response to the virus and help us build immunity to COVID-19. Additionally, "T-follicular helper cells" (T cells) are a type of immune cell that is activated by the mRNA vaccine. "Germinal center B cell responses" (GC B cells) are also activated by the mRNA vaccine.  mRNA vaccines also interact with dendritic cells. Dendritic cells help our bodies with transporting foreign invaders, like a virus or a vaccine, to the body's immune-boosting T cells, so that we can build up immunity to that foreign invader. Lastly, the mRNA vaccines also interact with cells in our muscles when the vaccine is injected.

EIDD-2801, also called Molnupiravir, is an oral antiviral drug that was developed by the Emory Institute for Drug Development (EIDD). It was originally developed to treat influenza. It is in Phase II/III of its clinical trials as a treatment for SARS-CoV-2 infection. Similar in function to Remdesivir, EIDD-2801 targets the enzymes in the COVID-19 virus and replaces them with another compound. This switching creates mutations in the virus that make it incapable of functioning. The nonprofit biotechnology company owned by Emory University, Drug Innovation Ventures at Emory (DRIVE) partnered with a biotechnology company in Miami, Ridgeback Biotherapeutics to start the clinical trials for this treatment. Ridgeback has partnered with Merck & Co. to develop and distribute EIDD-2801.

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.

Gelatin from pork and cow products is often used in vaccines to stabilize the drug's ingredients and ensure they remain effective through the distribution process.  The COVID-19 vaccines from Pfizer, Moderna and AstraZeneca do not use pork gelatin in their formulas, but there is widespread concern over vaccines from other companies, which have not released a list of their ingredients. Three of the companies that religious groups are concerned about most are Sinovac, Sinopharm, and CanSino Biologics, which have not released official statements about whether or not their products use pork-derived gelatin. Gamaleya Research Institute, Johnson & Johnson, Novavax, and Bektop have received limited approval for releasing their vaccines around the world, but have not noted whether or not they use gelatin in their formulas either. No other companies have declared that they are using pork products in their vaccines at this time though nearly all of them are still in the development, research and clinical trials phases.

Positive COVID-19 antibody tests and a prior COVID-19 infections do not guarantee immunity to the virus, making the COVID-19 vaccine recommended for individuals who have tested positive for the COVID-19 virus and/or for COVID-19 antibodies. With regards to safety and efficacy, so far the Pfizer and Moderna vaccine trials have concentrated on individuals who were not already previously infected with COVID-19, so it's still not clear what the effect of vaccination will be on those who have been previously infected with COVID-19 or have COVID-19 antibodies at the time of vaccination. In those trials, some individuals had prior infections, and evidence suggests that the vaccine was safe and effective for them. Receiving a vaccine even after infection is also common practice with other viruses, such as influenza and the Human papillomavirus (HPV). To help ensure safety, the Advisory Committee on Immunization Practices (ACIP) recommends waiting until you have recovered from the illness if experiencing symptoms before receiving the vaccine (typically 10 days after the onset of symptoms).

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.

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.

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.

Chlorine dioxide is not a potential cure or treatment for COVID-19 and no studies currently support its use with any evidence. Chlorine dioxide is a bleaching agent that can cause serious and even life-threatening illnesses. Though several warnings about this chemical being used in alleged COVID-19 treatments have been issued, products continue being sold with the promise to combat the virus. Chlorine dioxide is not meant to be swallowed by people in any capacity, let alone in treating an illness.  These products often describe this chemical as a liquid with 28% sodium chlorite solution and instruct users to mix it with citric acid before drinking. When the acid is combined with the sodium chlorite solution, it activates the acid to become chlorine dioxide.

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.

Type 2 diabetes is considered an underlying (pre-existing) medical condition that has the "strongest and most consistent evidence" for increasing the risk of severe illness due to COVID-19, according to the U.S. Centers for Disease Control and Prevention (CDC). In July 2020, U.S. health officials stated that almost 40% of people who have died with COVID-19 had diabetes. Beyond diabetes leading to COVID-19 complications, researchers are now studying the potential for COVID-19 to lead to diabetes. Medical experts have reported diabetes onset in patients who tested positive. In some cases, the patients appeared to have otherwise recovered from COVID-19, and/or had no previous history, genetic predisposition, or traditional risk factors (such as lifestyle factors) for diabetes. As of October 2020, over 300 doctors applied to share cases for review in a global registry on this topic led by King's College London. The U.S. National Institutes of Health (NIH) is also funding research on how COVID-19 may cause high blood glucose levels and diabetes. Additionally, doctors as well as researchers have been raising the alarm on how more children appear to be getting diagnosed with diabetes during the COVID-19 pandemic, compared to similar months in previous years. Prior to the COVID-19 pandemic, other viral infections including influenza and other coronaviruses have been linked to triggering Type 1 diabetes, but this is usually in people who are predisposed to developing diabetes. While researchers know that infections stress the body and can lead to higher blood glucose levels, researchers still have not fully understood why some people develop diabetes after infection and others do not. The connections between COVID-19 and diabetes are continuing to be studied. Diabetes is a disease where the blood glucose (sugar) levels are too high, and is generally differentiated into Type 1 (where the body cannot produce the insulin that is required to turn blood glucose into energy) and Type 2 (where the body does not respond well to insulin, allowing blood glucose levels to rise).