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Health Desk articles

Does wearing a face mask put you at higher risk of cancer?

Wearing a face mask does not put you at a higher risk of cancer. There is no current evidence linking the use of face masks to cancer, and science shows that any risks associated with wearing masks are low overall, while the benefits are high.  Because of how tiny oxygen and carbon dioxide molecules are, face masks neither decrease the amount of oxygen that enters a mask nor increase the amount of carbon dioxide that stays in a mask. As a result, face masks do not disrupt the body’s pH levels, affect the bloodstream, or alter one’s body in any way that would put someone at higher risk of cancer. The claim that wearing face masks causes cancer has been circulating on Facebook and other social media platforms, citing a January 2021 study that did not study face masks or mask wearing in general. An article from Blacklisted News falsely suggested that mask wearing can lead to reproduction of bacteria, which then leads to cancer. The articled stated that harmful microbes can grow in a moist environment, like the ones created around the mouth and face because of constant mask wearing. The article suggests that microbes can grow and replicate before traveling through the trachea into blood vessels in the lungs. From there, they allege the the microbes cause an inflammatory response. It's true that oral bacteria can contribute to oral infections, dental plaque, and cancer. However, bacteria is also a normal part of our skin and other organs. It can contribute to health in positive and negative ways. The study that linked mask wearing to the development of advanced lung cancer did not involve long-term mask wearing as part of the study. The article that wrote about it falsely assumed that masks could be the cause of this bacteria, rather than its normal presence in the human body and microbiome. There is no evidence that mask wearing can pose a danger to health, including altered carbon dioxide and oxygen levels. Bacteria can build up over time in a mask, so they should be cleaned and dried properly. This build up does not cause cancer.  The American Lung Association verified that masks cannot cause lung cancer and the United States Centers for Disease Control and Prevention noted that any carbon dioxide build up in masks should not impact people who wear face masks in order to prevent COVID-19 infections and transmission.

What does colder weather mean for the spread of COVID-19?

We do not know how the COVID-19 virus will impact people during colder winter months, but many experts predict higher rates of transmission and mortality than during the warmer, summer months. This is likely due to the impact cold weather has on human behavior such as forcing people inside where higher temperatures are preferred and ventilation is not sufficient to combat the spread of the virus. With groups of people congregating in confined spaces with limited airflow, the virus is able to circulate easily through aerosolized particles and respiratory droplets. Additionally, since a large percentage of COVID-19 have asymptomatic infections but they are still able to transmit the virus, many infected people are likely not restricting their movements to one quarantined room or area or taking necessary distancing or masking protocols. Traditionally, viruses like influenza and the common cold tend to increase amounts of infections in the winter and decrease in the summer. As with these other respiratory viruses, COVID-19 transmission will be impacted dramatically by control and prevention measures like social distancing, masking, and vaccination. The more people who engage in these activities, the more likely infections can be prevented. Though some viruses do not like humid, hot conditions, COVID-19 has been shown to spread rapidly in some regions during warm spring and summer months in both hemispheres. A study from October 13, 2020, before widespread prevention measures were undertaken showed that infections increased more quickly in places with less UV light and suggested that without any interventions, case rates may be highest in the winter and lower in the summer. However, weather itself does not appear to have an impact on the ability of the virus to spread though colder weather may make it more difficult for the body to fight respiratory infections. At this point, it is unknown whether or not COVID-19 will become a seasonal virus like influenza but we should expect any event that brings together people in closed environment can lead to an increased spread of the virus.

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

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

Is indoor dining safe now, especially in covered tents?

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

What do we know about the Regeneron cocktail for COVID-19?

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.

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

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

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

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

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

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

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

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

What do we know about controlling the spread of COVID-19 through hyper-local measures?

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.

Does COVID-19 impact young people?

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.

What do we know so far about airborne transmission and how does it differ from respiratory droplet transmission?

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.

Is it safe to wear a mask?

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.

What do we know about pregnancy and COVID-19?

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.

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

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

What are COVID-19 risks for cancer survivors (5+ years)?

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.

What do we know about new strains of this virus that is more infectious than the first strains?

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. 

Can the virus be transmitted through the air?

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.

What do we know so far about face masks and their ability to prevent COVID-19?

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.

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

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

Why are there multiple COVID-19 vaccines?

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

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

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

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

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

How are vaccines studied for long-term side effects?

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

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

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

What do we know so far about COVID-19 and alkalinity?

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. 

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

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

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

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

How do mRNA messenger vaccines work?

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

What do we know about the smallpox vaccine?

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