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Health Desk articles

Can animals with no symptoms spread COVID?

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

Is indoor dining safe now, especially in covered tents?

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

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

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

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.

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. 

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.

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.

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: <>

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.

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

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

How are vaccines studied for long-term side effects?

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

Why 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 AstraZeneca 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.

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."

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

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

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

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

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

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

How do mRNA messenger vaccines work?

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

What do we know about how curfews work?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.

Why is Janssen starting a clinical trial with two doses?

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

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

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

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

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

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

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

Can convalescent plasma help treat COVID-19?

When someone has been infected with COVID-19, their body's immune system produces antibodies (special proteins) that work to destroy the virus. These antibodies can usually be found in someone's blood after they recover from the virus, specifically in a portion of the blood called 'plasma.' Antibodies in plasma help an infected person fight off the virus, so researchers are studying whether transferring plasma from patients who have recovered from COVID-19 (also called 'convalescent plasma') can help strengthen people's immune systems to fight off the infection. This experimental use of convalescent plasma for COVID-19 is not currently an approved treatment by the World Health Organization, and there is a lack of scientific evidence to allow convalescent plasma to be routinely prescribed to patients with COVID-19. However, there are potential benefits to convalescent plasma use that have been demonstrated with other diseases. These benefits are believed to outweigh the potential risks. Given the current lack of scientific evidence, the use of convalescent plasma has not been formally approved by the US Food and Drug Administration (FDA). On August 23, 2020, however, the administration did issue an emergency use authorization (EUA) for investigational convalescent plasma use for the treatment of COVID-19 in hospitalized patients. This means that convalescent plasma is now regulated as an investigational treatment for COVID-19, but it not yet fully approved for use. More than 70,000 patients have received convalescent plasma in the US. Recent studies are inconclusive and have not shown significant benefits for patients who receive convalescent plasma, but more research needs to be conducted before scientists reach a consensus about the benefits vs possible negative impacts plasma may have in patients with COVID-19.

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

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

Can someone be infected with COVID-19 more than once?

We are still learning a lot about what kind of immunity a person has after being infected with COVID-19, and how long that immunity lasts. A a small number of people have reportedly become reinfected with virus following an initial infection and research is ongoing. According to the US Centers fo Disease Control and Prevention (CDC), "reinfection means a person was infected (got sick) once, recovered, and then later became infected again. Based on what we know from similar viruses, some reinfections are expected. We are still learning more about COVID-19." In a press conference on December 4th, 2020, the World Health Organization acknowledged emerging evidence that suggests that COVID-19 immunity is unlikely to be lifelong, which suggests reinfection may be possible. The most reliable way to measure immunity to COVID-19 is unclear, and, whether from infection or vaccination, scientists still do not know how long immunity to COVID-19 may last. Though reinfection has been documented, there are many ongoing questions about whether or not reinfection poses an ongoing risk, how common it is, and what kind of immunity to the virus people might obtain once they have been infected. Currently researchers believe that most people will be protected from reinfection for up to six months following infection, but research is ongoing. There are multiple pre-print studies with large participant groups that suggest immunity does last for up to six months but decreases over time. Antibodies decrease more quickly in young adults who have had an asymptomatic infection. Pre-print studies have also suggested that reinfection is possible. It is important to note that there is a shortage of peer-reviewed papers (so other scientific experts are not yet able to rigorously study the data or full results). It is also important to note that antibody levels may not be a strong indicator of immunity against the virus and likelihood of reinfection. To prevent infection, reinfection, and spread of COVID-19, experts recommend frequent hand washing, social distancing (6 feet/2 meters apart), avoidance of crowded areas (especially indoors), wearing a face mask (though the U.S. CDC now suggests wearing a cloth mask over a surgical mask or a high grade respirator), and staying home when you are sick or know that you have been exposed to COVID-19.

What short and long-term effects does COVID-19 have on other body parts, including lungs, brain, heart and kidneys?

Many people infected with COVID-19 have mild or no symptoms, but some of the short-term impacts reported by people with mild symptoms include shortness of breath, fever, cough, fatigue (tiredness), and body aches. For more severe cases, short-term impacts may include respiratory (breathing) failure, confusion or other neurological problems, and kidney or heart damage due to a lack of oxygen or blood clots that can sometimes cause long-term problems. The worse the symptoms of COVID-19 are, the more likely major organs are to be negatively impacted. COVID-19 may impact organ systems directly (in the case of the virus causing inflammation in the lungs and airways) or indirectly (where organ damage is caused by illness that is a result of COVID-19 infection, but the organ damage is not caused by the virus infecting the organ directly). Recent studies document long-term impacts of COVID-19 on different organs in the body, including lung scarring, limited lung capacity, neurocognitive impacts, heart damage, renal failure, and more. Lungs: Though it can impact other organs, COVID-19 is primarily thought of as a lung (or respiratory) illness. Patients with lung problems like asthma, chronic obstructive pulmonary disease (COPD), and other chronic (long-term) lung diseases may be at higher risk of having complications from COVID-19. In any infected patient, COVID-19 may cause pneumonia (where the lungs fill with fluid), acute respiratory distress syndrome (ARDS), and sepsis (a bloodstream infection). Lung problems may be short or long term, and experts have suggested that it can take months, possibly even more than a year, for lung function to return to normal after a COVID-19 infection. Early rehabilitation has been shown to improve respiratory (breathing) problems in patients who have had severe COVID-19. Heart: Studies have shown that heart problems are also common. One German study reported that 78 out of 100 patients recovering from a COVID-19 infection had heart-related problems, such as inflammation and scarring, that could have serious consequences. In addition, heart problems have been reported in 40% of COVID-19 deaths. In September, US CDC reported that heart conditions like myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the covering of the heart), are associated with COVID-19. Such heart damage might also explain long-term symptoms like shortness of breath, chest pain, and heart palpitations. Although rare, severe heart damage has also been seen in young, healthy people. Kidneys: The American Society of Nephrology reported that approximately 50% of patients with severe cases of COVID-19 in intensive care experience kidney failure. During July 2020, the impacts of COVID-19 on the kidneys made the news, following updated recommendations from the American Society of Nephrology. On this topic, Mount Sinai Health System Associate Professor of Nephrology and RenalytixAI Co-Founder, Dr. Steven Coca warns about the rise in “chronic kidney disease in the U.S. among those who recovered from the coronavirus...Since the start of the coronavirus pandemic we have seen the highest rate of kidney failure in our lifetimes. It’s a long-term health burden for patients, the medical community — and the U.S. economy.” New research and media reports are continuing to be released. Brain: Emerging evidence has revealed that some COVID-19 patients experience neurological symptoms in the brain, spinal cord, nerves, and ganglia (cell bodies that relay nerve signals). Researchers believe that these effects are an indirect impact of COVID-19 (meaning these effects occur because of illness related to COVID-19, but not as a direct result of the virus entering the tissue). Studies from around the world have reported neurological symptoms in COVID-19 patients ranging from brain inflammation and delirium to nerve damage, stroke, and impaired consciousness in as much as 30% of patients. Researchers have long been concerned about the risks of post-traumatic stress, dementia, and delirium in patients who require intensive care (even without COVID-19). The long-term implications of COVID-19 on the brain and nervous system are still unclear, since COVID-19 is a new disease and there has not been enough time to observe patients over long periods of time. Neurological complications have, however, been reported during previous epidemics, such as the Severe Acute Respiratory Syndrome (SARS) epidemic in 2003 and the Middle East Respiratory Syndrome (MERS) outbreak more recently in 2012. Since this is a new illness, the real long-term impacts remain unknown. The longer-term effects of COVID-19 are still being studied. Exhaustion, anxiety, dizziness, headaches, muscle aches, loss of taste and smell, and difficulty breathing are often reported in patients who experience symptoms for weeks following their infection with COVID-19. For some people infected with the virus, symptoms have lasted longer than 100 days.

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.

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

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

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

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

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

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

What do we know about calprotectin and COVID-19?

Calprotectin is a type of protein that is released into the body by neutrophils (a type of white blood cell). Neutrophils help heal damaged tissues and stop infections from spreading. When there is any type of swelling in a person, the amount of neutrophils produced by the immune system increases naturally, in order to help protect and defend the body. When there is inflammation in the gastrointestinal (GI) tract (the digestive system in humans and animals that help them digest, absorb, and discard food and liquids), neutrophils move to that area and release the calprotectin protein to help protect and defend the body. Because of this, studies have shown that increased levels of calprotectin in the body are linked to higher levels of inflammation in the GI tract, so calprotectin levels are often tested in people with gastrointestinal issues to determine whether or not they have illnesses like inflammatory bowel disease or other infections. Despite calprotectin normally being used as a marker for inflammation in the intestines, new research claims that measuring levels of this protein might help determine whether or not people who have tested positive for the coronavirus may develop more severe symptoms. Recent research in a pre-print study and a Letter to the Editor (in the Journal of Infection) shows a potential link between the levels of calprotectin in people infected with COVID-19 and more severe cases of the virus. In another pre-print study (which should not be used to guide medical treatments or practices) researchers found a potential link between higher levels of calprotectin in the body of COVID-19 patients with a higher number of patients who require breathing support with a ventilator (a machine that makes sure your body gets enough oxygen by moving air in and out a patient's lungs).  Both of the studies suggest that testing levels of calprotectin in people with the virus might help doctors predict how severe each patient's symptoms and outcomes might be. Studies are ongoing, but there is not enough evidence at this time to support this finding and no scientific consensus whether or not calprotectin can serve as a prediction of how serious the virus will be in some patients. Researchers will continue studying calprotectin in COVID-19 patients, but for now, calprotectin is still used primarily as a way for doctors to see if patients have inflammation in their intestines.

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

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

What is the difference between a vaccine's effectiveness and its efficacy?

Though vaccine efficacy and vaccine effectiveness are similar terms and are often used interchangeably, the differences between the two are important. In this entry, we rely on the United States Centers for Disease Control and Prevention's (U.S. CDC) definitions of effectiveness and efficacy. When a new vaccine is being developed and studied in clinical trials, scientists report on vaccine efficacy. Efficacy is a term used to describe how well the vaccine protects clinical trial participants from getting sick or getting very sick. The term does not describe how well a vaccine works on the general public. The efficacy of a vaccine reflects ideal circumstances, like a research trial, which are different than real-world conditions. Once a vaccine is made available for large population groups, vaccine effectiveness can be measured. Effectiveness is the amount of protection given by a vaccine in a certain population when its used under field conditions (somewhat normal practices, less than perfectly controlled like in a research study). It considers other factors like population-level differences in health status, weight, age, and other factors across communities. Effectiveness is a more reliable and accurate term for how helpful a vaccine is at preventing disease in daily life when people are doing regular community-based activities like socializing, going to work or school, and grocery shopping.

What do the efficacy results of Pfizer's clinical trial mean?

On November 18th, 2020, Pfizer announced that its experimental COVID-19 vaccine (BNT162b2) prevented infection in 95% of overall participants who received the drug company’s late-stage clinical trial dose. In adults over 65 years of age, the vaccine was effective in over 94% of volunteers. These early results exceeded the minimum United States Food and Drug Administration (U.S. FDA) target of 50% efficacy—but it is important to reiterate that no vaccine is ever 100% effective. It is impossible to know how well a vaccine actually works until it is deployed  in the real world and given to large populations, not just volunteer participants in a trial.  While the current data is promising, it has yet to be evaluated by the U.S. FDA, and more information is needed before Pfizer can pursue approval for the vaccine. The company has concluded its phase III trial but will continue to monitor patients for any adverse reactions or events. Additionally, to ensure that there are not major safety concerns, the U.S. FDA is requiring manufacturers to provide at least two months of follow-up data for at least half of the volunteer participants. Most serious side effects from vaccines occur within about six weeks after the vaccine is given. In vaccine clinical trials, any observed impacts of the vaccine on volunteer participants are eventually considered side effects with more serious side effects causing the trials to pause or stop completely. No safety concerns about these potential side effects have been reported so far. Pfizer recently stated that the only side effects that occurred in more than 2% of participants was fatigue at 3.8% and headache at 2.0%. 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. This vaccine requires an initial injection followed by a secondary shot called a “booster” to achieve its full level of protection. The vaccine was found to be effective against COVID-19 beginning 28 days after the first dose. The clinical trial included more than 43,000 volunteer participants, many of whom already received two doses of the vaccine. In the interim analysis, there were 94 cases of COVID-19 in trial participants, and the study continued until there have been 164 cases of COVID-19 among study volunteers. It is important to note that these study results may not play out the same under “real life” circumstances because of differences in health status, weight, age, and other factors across communities. While Pfizer has reported that 42% of participants are from “diverse backgrounds,” the study population may not reflect the diversity of our global populations and communities despite the vaccine being effective across age, gender, race and ethnicity demographics in the trials.

What are some of the birth and infant outcomes following COVID-19?

Maternal COVID-19 infection during pregnancy may be a risk factor for premature birth. In November 2020, the US Centers for Disease Control and Prevention (CDC) released outcomes data for infants born to birth givers who had been diagnosed with COVID-19 during pregnancy. The data was collected between March and October of 2020 and included a total of 3,912 infants. Incidence of prematurity in study participants was higher than average, which suggests that maternal COVID-19 infection acquired pregnancy (not in general) may be a risk factor for prematurity. This report found that 12.9% of infants born to individuals who had been diagnosed with COVID-19 during pregnancy were born prematurely (<37 weeks gestation), which is greater than the national estimate of 10.2%. In the U.S., COVID-19 has not impacted all communities equally; non-Hispanic Black and Hispanic communities have been unduly impacted by the virus. Racial and ethnic disparities also exist in overall health outcomes and impact maternal morbidity, mortality, and adverse birth outcomes. In this study, non-Hispanic Black and Hispanic women were disproportionately represented, and the authors note that further observation and analysis of outcomes by race and ethnicity is needed. Another study published in the Lancet in October 2020 found that the incidence of preterm births went down in the Netherlands after the implementation of COVID-19 pandemic mitigation policies. The authors suggest that some of the observed decrease in preterm births could be related to reductions in maternal exposure to air pollution and reductions in pregnant women seeking obstetric care that induces preterm birth. While the impact of COVID-19 on pregnancy outcomes remains under investigation, the CDC continues to encourage pregnant people to attend prenatal care appointments; practice handwashing, social distancing, and mask wearing (preferably a cloth mask over a surgical mask); and avoid crowds especially in indoor areas to prevent COVID-19 infection. They also suggest that providers counsel pregnant individuals on steps to prevent COVID-19 infection.

What do we know so far about using VCO for COVID-19?

Virgin coconut oil (VCO) is being studied in the Philippines and other countries as a potential supplementary treatment for COVID-19 — that is, a potential additional treatment used in combination with other COVID-19 treatments. These community-based trials are being carried out by the Filipino Department of Science and Technology (DOST) at the Sta. Rosa Community Hospital in Laguna, and involved both probable cases of COVID-19 (i.e. highly suspected cases) and mild cases of COVID-19. There are also two trials being carried out at the Philippine General Hospital (PGH) looking into the effects of VCO on moderate cases of COVID-19 or those who are hospitalized. These two sets of studies aim to understand if VCO can shorten the COVID-19 recovery time, prevent further complications, and prevent hospitalization time. These studies follow 6 months of laboratory experiments that found VCO to decrease the coronavirus count by 60 to 90% for mild to moderate cases of COVID-19. If proven to be effective with sufficient evidence in the community-based trials, VCO could be a safe and affordable supplementary treatment for COVID-19. It is important to note that these studies are still in development and that The World Health Organization (WHO) does not support the use of any specific medication to treat, cure, or prevent COVID-19. While coconut oil is safe in certain doses, more evidence is needed to understand its effect on COVID-19 and it should not be used as a COVID-19 treatment or prevention medication. 

What do we know about using CT scans to diagnose COVID-19?

High levels of false negatives from RT-PCR testing and long waits to receive test results have led many medical institutions to use chest CT (computed tomography) scans to diagnose COVID-19. Several studies, mostly conducted in China, have shown higher sensitivity of CT scans in detecting coronavirus when a PCR test showed a negative result. However, this does not mean that CT scans alone should be used for disease identification. CT scans can also miss detecting the virus and be misidentified with other pulmonary infectious/ viral pneumonias. Some experts believe that CT scans do not add any diagnostic value, while others believe that from a population health perspective during a pandemic, CT scans should be used to isolate suspicious cases for COVID-19, because of its high sensitivity and rapid identification. Some studies support a dual approach of CT scans and RT-PCR, or the use of chest CT scan to screen for coronavirus when RT-PCR tests are negative. CT scans are relatively expensive compared to swab tests and also expose patients to a small dose of radiation. Some experts argue that because CT scans are resource intensive, they cannot be used as a population-wide testing tool. The American College of Radiology (ACR) and US CDC recommend against using Chest CT scanning for screening or diagnosis of coronavirus disease 2019. On the other hand, the National Health Commission of China has encouraged the use of Chest CT scans for diagnosis. Local resource constrains and expert physician advise on individual patient conditions are important factors in deciding on the use of CT scans or not.

Do positivity rates show herd immunity has been reached?

Positivity rates of COVID-19 are not an indication of herd immunity. The rate of positivity in a community is defined as the percentage of total COVID-19 tests that come back positive out of all the people who have been tested in that community or population, within a given time period. Positivity rates can indicate an increasing outbreak, if the rate of positive tests increases while the amount of testing stays the same. A positivity rate can also indicate that not enough tests are being conducted, if more tests come back with positive results but tests were conducted on a smaller percentage of the population than the week before. Neither of these have anything to do with herd immunity. "Herd immunity" refers to a given percentage of people that need to become immunized to a virus, through vaccines or through becoming infected in a natural setting, against a virus in order to provide safety for an entire population—i.e. the herd. It's the idea that if most people are immune, then the rate of transmission will be low or non-existent. COVID-19 is not vaccine-preventable at this time and we know very little about how we become immune to the virus. Herd immunity would require a large majority of the population to become infected with the virus and obtain long-term immunity to COVID-19 — but since we know so little about long-term immunity right now, we can't say anything about herd immunity in relation to COVID-19. Percent positive rates of COVID-19 are not being used to determine herd immunity in a community because we know so little about immunity in general, and because positive rates can mean a wide variety of things. If there is a higher percentage of positive test results in a region, this is not indicative of any potential for herd immunity, because evidence to support long-term immunity is lacking.

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

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).

What do we know about false positives with rapid antigen testing?

Antigen tests for COVID-19 have many advantages, including rapid results, cheap production costs, and a high rate of accurate test results for people who are actively infected with COVID-19. However, one of the major downsides of these tests is their high rate of false negative results (having a negative test result even if you are actively infected with the virus). Comparatively, false positive test results, which incorrectly show that a healthy person is infected by the virus when they are not, are very rare in tests that have been approved by regulatory agencies like the U.S. Food and Drug Administration (FDA). Despite having low rates of false positives, these types or errors in antigen tests still exist due to technical issues like handling, contamination, or test errors. These considerations have a large impact as their effects can directly result in health impacts for people who test positive (but are not) and are quarantined with people with active infections or receive treatments like medication when it may be harmful. While most newer antigen tests aim to accurately identify people with active COVID-19 infections at least 80% and 90% of the time (true positive rate), some antigen tests have been reported to have false positive or false negative rates as high as 50%. Several experts recommend using a second test to confirm a patient is truly negative or positive, particularly when patients may have no symptoms or have not been exposed to people who tested positive for the virus. While antigen tests can usually diagnose active COVID-19 infections, they are more likely to miss an active infection in comparison to molecular tests like polymerase chain reaction (PCR) tests. Several countries have begun authorizing the use of newer antigen tests that report lower rates of false positives and false negatives. For example, as of early December 2020, the U.S. FDA has granted Emergency Use Authorizations (EUAs) for a handful of the more accurate antigen tests that are available. As more of these tests are produced and used on a wide scale, we hope to learn more about their accuracy and achieve as sensitive (correctly identifying those who are are actively infected with the virus) and specific (correctly identifying those who do not have an active infection) as possible.

Why do vaccine clinical trials sometimes stop or suspend operations?

Pausing or suspending clinical trials occurs frequently in the development of new medications and vaccines. This is because every clinical trial is overseen by a data and safety monitoring board that routinely looks at data from the different trial phases to see if there are any harmful or adverse issues happening in trial participants. The board also monitors to see if there is any evidence of the vaccine being effective. If the board has any concerns at any point during a clinical trial, they will suggest stopping a trial until they can determine a) what caused the patient(s) to develop a harmful medical issue, b) if people receiving the vaccine in the clinical trials are doing much better than those who didn't, or c) if people who received the vaccine are doing much worse than the people who didn't. These prescheduled checks by the boards may sound alarming, but they occur frequently in all phases of clinical trials. As vaccines move into the third phases of clinical trials, in which they are given to tens of thousands of people, it is not surprising that one or more people develop a medical issue which may or may not be related to the vaccine itself. Lists of side effects that you see on medications stem from these clinical trial phases. Studies also have pre-set protocols and criteria that determine what events will cause them to pause or stop their research phases. They cannot ethically continue with the trial if they have reasons for concern about the health of clinical trial participants who have received their vaccines.

What does the science say about COVID-19 on surfaces?

The virus that causes COVID-19 primarily spreads through close, person-to-person contact, not through surface contamination. However, the virus can live on surfaces and the amount of time that SARS-CoV-2 can survive on a surface depends on the material of the surface. According to a recent study published in the Virology Journal, depending on the temperature, COVID-19 survived on different surfaces from a few hours to several days, with a half-life (time taken for 50% of the virus to no longer be infectious) of up to 2.7 days. The virus remained infectious on stainless steel, polymer and paper notes, glass, cotton and vinyl for much longer at 20°C as compared to 40°C. In practice, the amount of the virus on a surface usually drops dramatically in the first few hours. It is also important to note that even though some of the living virus might still be detected on a surface after several hours or days, it might not be present in a large enough quantity to make someone sick. The recent findings, however, suggest that the virus can remain infectious for longer periods of time than considered earlier, especially at lower temperatures. If a person touches a contaminated surface with traces of the virus and then touches their eyes, nose, or mouth, they could become infected if the surface contains large amounts of the virus. This is why it is important to clean and disinfect any surfaces that people might come into contact with, especially those like doorknobs, cell phones, light switches, handles, countertops, sinks, toilets, and more. If possible, people should try to avoid touching high-contact surfaces in public. Washing your hands for 20 seconds, avoiding touching your face, maintaining six feet (two meters) of distance and wearing a mask (the U.S. Centers for Disease Control and Prevention recommends wearing a cloth mask over a surgical mask for increased protection) are key steps in combatting the spread of the virus.

What are the pros and cons of each available COVID-19 test?

There are 3 main types of COVID-19 tests. Two are diagnostic (molecular and antigen tests), which means they show active infections. One test type looks for antibodies that occur in the body following a previous infection (also known as antibody tests). 1) Molecular tests (polymerase chain reaction (PCR) tests, viral RNA tests, and nucleic acid tests) are completed using nasal swabs, throat swabs, and through testing bodily fluids like saliva. These tests look for evidence of genetic material from the virus. They have a low rate of false-positive results (when a test says you have the virus, but you do not) but a higher rate of false-negative results (when a test says you do not have the virus, but you really do). Using a deep nasal swab PCR test that collects viral material at the back of nose, near your throat, is the most trusted option of the molecular tests. That's because it is the most accurate, and there is a higher amount of virus in that area of the body than anywhere else. These tests are highly sensitive, which means they are able to accurately determine when a person actually has an infection. However, the method is uncomfortable, the results can take hours to days, they are the most expensive to do, and can be overly sensitive and pick up inactive virus fragments when a person no longer has an active infection. 2) Antigen tests are completed using nasal or throat swabs and they look for proteins (antigens) from the virus. Most people are familiar with this technology because it is commonly seen in pregnancy tests. These results are available in as little as 10 minutes, the test is less expensive than other forms, and uses simpler technology than PCR tests. These tests are usually highly accurate for positive results, but might require a molecular test to confirm if a person really is negative because they can often have a high rate of false-negative results. 3) Antibody tests are different than diagnostic tests because they are blood tests that look for a former COVID-19 infection through the presence of antibodies,  a protein that latches on to foreign invaders in the body - in this case, COVID-19 - neutralizes them, and then remains in a person's system after infection. A person produces COVID-19 antibodies when they are exposed to the virus, so an antibody test can show whether or not someone has been infected in the past. Antibody test results are usually available within a few days. However, these tests produce a lot of false-negatives and we don't know enough about how long antibodies last after exposure or infections, how long any immunity might last, and how many antibodies are needed in a person who has recovered from the virus to show a positive test result. There are many different elements involved in how accurate or reliable tests may be at the time they are taken and at the stage of exposure and infection each person is presently in, and every testing type has different strengths or weaknesses. It is important to remember that the best test for each person should be chosen with their doctor on an individual basis.

What are the markers of a second COVID-19 wave?

There is no single definition of a “wave” of a disease in public health. Defining a disease wave varies across scientific literature and even by the scientist you ask. This lack of continuity has to do with the complexity of disease outbreaks, and in particular 1) the ways in which diseases affect different populations at different times, 2) the difficulty in accessing accurate data, and 3) most importantly, the lack of a standardized definition of a disease wave. We do, however, know a disease wave when we see one in public health, and agree on indicators of second, third, and fourth waves, and beyond. A disease wave can be thought of as a sustained surge (or spike) in cases, following and relative to a period of sustained low cases. Think of a line on a graph that curves high (first wave), dips low (end of the first wave), then curves high again (second wave).  In defining the end of a first wave for the U.S., on June 18 2020, Dr. Anthony Fauci, U.S. White House advisor and director of the National Institute of Allergy and Infectious Diseases, told the Washington Post that in order to consider the first wave in the U.S. technically "over", we would need to see a specific region, state, or city have a sustained decrease of positive infection rates until they were in the low single digits.  This is just one expert's definition, however, and just because a region may not have reached single digits of positive test rates does not mean they might not be considered by some to be in a second wave now, and by others in a third wave, if they’re seeing a significant and sustained surge in positive rates compared to what that area’s positive test rate number was previously. 

Can pink eye be a symptom of COVID-19?

Conjunctivitis, also known as pink eye because it can cause the white of the eye to appear red or pink, is an inflammation or infection of the conjunctiva (a transparent membrane that lines the eyelid and covers the white part of the eye). Conjunctivitis can have different causes, including bacterial infections and viral infections (including adenoviruses, which cause the common cold, and the novel coronavirus that causes COVID-19). The appearance of reddish eyes can also be due to allergies, dryness, fatigue, or other factors and does not necessarily mean a person has conjunctivitis. Some research studies have identified conjunctivitis as a possible symptom of COVID-19, including a study of 38 patients with COVID-19 in China, which found that 12 of the patients had ocular or eye-related symptoms such as conjunctivitis. Patients with more severe COVID-19 were more likely to have ocular symptoms, and 1 patient in the study presented with conjunctivitis as their first symptom. In Canada, a case study was published on a female patient with COVID-19 who had severe conjunctivitis and minimal respiratory symptoms. In the U.K., another case study of a male patient with COVID-19 found that conjunctivitis was a symptom in the middle phase of COVID-19 illness. A review of ocular symptoms in COVID-19 patients that was published in August 2020 found no reports of COVID-19 becoming sight-threatening. The American Academy of Ophthalmology has stated that conjunctivitis can be an infrequent symptom of COVID-19, estimated to occur in 1% to 3% of patients who test positive for COVID-19. A meta-analysis of 1167 patients in 3 studies found that the overall rate of conjunctivitis was 1.1%, with the rate being 3% in patients with severe COVID-19 and 0.7% in patients with non-severe COVID‐19. Conjunctivitis may be more common as a COVID-19 symptom in children. A study of 216 children with COVID-19 in China found that 22.7% showed an ocular symptom, including conjunctivitis. Since conjunctivitis is not among the most common COVID-19 symptoms and can have underlying causes that are unrelated to COVID-19, many public health and medical experts are advising that adults and children with suspected conjunctivitis seek care for their eyes. If someone with conjunctivitis has been at risk of exposure to COVID-19, a healthcare provider can help with determining whether a person with conjunctivitis should also get tested for COVID-19.

Is the isolation period of COVID-19 patients being re-evaluated? Is there any research that shows the virus stays in the body for a period of 90 days?

Public health agencies have been updating their recommendations for isolation during the COVID-19 pandemic, as the scientific understanding of how long someone can be sick and infectious to others evolves. For example, the U.K. Chief Medical Officers extended their isolation period for people who test positive from 7 days to 10 days in July 2020, the Indian Ministry of Health and Family Welfare reduced their isolation period for international travelers from 14 days to 7 days in August 2020, and the French Prime Minister reduced their self-isolation period for people who test positive from 14 days to 7 days in September 2020. The World Health Organization (WHO) criteria for releasing COVID-19 patients from isolation was updated in late May 2020 to recommend that people who are asymptomatic remain in isolation for 10 days, and that people with symptoms remain in isolation for at least 10 days after symptom onset and at least another 3 days without symptoms (or a minimum of 2 weeks). One large contact tracing study found that people were less likely to become infected with COVID-19 when exposed to a positive case after 6 days or more of the infected person's symptom onset, which is in alignment with how certain countries are now using 7 days as their recommended isolation period. Other studies suggest people with mild to moderate cases of COVID-19 may be infectious up to 10 days after the symptom onset, with a documented case report of a person with mild COVID-19 who was shedding "replication-competent" virus specimens (an indicator for being able to infect others) for up to 18 days after symptom onset. Furthermore, some research suggests that people with more severe cases of COVID-19 or who are severely immunocompromised may remain infectious for up to 20 days after symptom onset. In terms of COVID-19 patients having evidence of the virus in their bodies for long periods of time, there have been studies suggesting that people with COVID-19 can continue to shed detectable virus specimens from their upper respiratory system for up to 3 months (or about 90 days) after symptom onset, but it is important to recognize that this may not be at a concentration that's high enough for the virus to replicate and infect others. People who continue to shed virus specimens for many weeks or even months after symptom onset are sometimes called "persistently positive," but according to a review of studies by the U.S. Centers for Disease Control and Prevention (CDC), there is currently little evidence of transmission by "persistently positive" people who have clinically recovered from COVID-19. Most of the data on how long people with COVID-19 remain infectious comes from adults, so more research is needed to understand how long children and infants may remain infectious. Additionally, research is ongoing on how the virus is shed in certain situations, such as in people who are immunocompromised. As more research findings emerge, public health guidelines will likely be updated around the recommended isolation periods for people with COVID-19 or who have been in contact with someone confirmed to have COVID-19.