FDA Statement on Following the Authorized Dosing Schedules for COVID-19 Vaccines
On January 4, U.S. Food and Drug Administration (FDA) Commissioner Stephen M. Hahn, MD, and Director of the FDA’s Center for Biologics Evaluation and Research Peter Marks, MD, PhD, issued the following statement on FDA-authorized dosing schedules for each COVID-19 vaccine.
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Two different mRNA vaccines have now shown remarkable effectiveness of about 95% in preventing COVID-19 infection in adults. As the first round of vaccine recipients become eligible to receive their second dose, we want to remind the public about the importance of receiving COVID-19 vaccines according to how they’ve been authorized by the FDA in order to safely receive the level of protection observed in the large, randomized trials supporting their effectiveness.
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. Without appropriate data supporting such changes in vaccine administration, we run a significant risk of placing public health at risk, undermining the historic vaccination efforts to protect the population from COVID-19.
The available data continue to support the use of two specified doses of each authorized vaccine at specified intervals. For the Pfizer-BioNTech COVID-19 vaccine, the interval is 21 days between the first and second dose. For the Moderna COVID-19 vaccine, the interval is 28 days between the first and second dose.
What we have seen is that the data in the firms’ submissions regarding the first dose is commonly being misinterpreted. In the phase III trials, 98% of participants in the Pfizer-BioNTech trial and 92% of participants in the Moderna trial received two doses of the vaccine at either a 3- or 4-week interval, respectively. Those participants who did not receive two vaccine doses at either a 3-or 4-week interval were generally only followed for a short period of time, such that we cannot conclude anything definitive about the depth or duration of protection after a single dose of vaccine from the single-dose percentages reported by the companies.
Using a single-dose regimen and/or administering less than the dose studied in the clinical trials without understanding the nature of the depth and duration of protection that it provides is concerning, as there is some indication that the depth of the immune response is associated with the duration of protection provided. If people do not truly know how protective a vaccine is, there is the potential for harm because they may assume that they are fully protected when they are not, and accordingly, alter their behavior to take unnecessary risks.
We know that some of these discussions about changing the dosing schedule or dose are based on a belief that changing the dose or dosing schedule can help get more vaccine to the public faster. However, making such changes that are not supported by adequate scientific evidence may ultimately be counterproductive to public health.
We have committed time and time again to make decisions based on data and science. Until vaccine manufacturers have data and science supporting a change, we continue to strongly recommend that health-care providers follow the FDA-authorized dosing schedule for each COVID-19 vaccine. The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
(Reuters Health) - Two new literature reviews suggest face masks provide some protection to the wearer and when universally worn by the general public they substantially reduce the spread of the new coronavirus. The reviews, published in Annals of Internal Medicine, look specifically at the effect of masking on COVID-19 transmission. One report analyzed the impact of masking by the general public on the spread of the virus. Researchers reviewed over 100 research articles and concluded that masking could substantially reduce the spread of viruses, including SARS-CoV-2, without risks to the wearer. "Our review clearly shows that masks and face coverings worn by members of the public are highly effective in reducing the spread of SARS-CoV-2," said study leader Dr. Thomas Czypionka, head of the Health Economics and Health Policy Unit at the Institute for Advanced Studies in Vienna, Austria and visiting senior research fellow at the London School of Economics and Political Science. "A growing body of evidence suggests that the virus is transmitted through drops in close contact situations and through aerosols, small particles hovering in the air for extended periods of time that accumulate especially in closed and crowded spaces," Dr. Czypionka said in an email. "Such situations should be avoided of course, but if you can't - for example, on public transport, in shops etc. - masks and face coverings can substantially reduce the risk of infection, mainly by source control, that is, by trapping the particles exhaled. There is also laboratory evidence that they may protect the wearer as well. Therefore, masks can literally save lives, and in a situation like this, with community spread, they should be widely used." There are many misconceptions about masks, Dr. Czypionka said. "One is that they lead to physiological changes like elevated carbon dioxide levels or decreased oxygen levels in the blood," he added. "Masks and face coverings may cause discomfort for some people, but we found no empirical evidence for masks to cause harm." The second report -- an update to a "living review" of data on mask use by the general public and by health care workers -- focused mainly on three studies: one study of masking and the prevention of SARS-CoV-2 in a community setting (the DANMASK trial) and two studies of mask use in healthcare settings. The DANMASK open label trial, which included 6,024 community dwelling adults in Denmark, found that the incidence of SARSCoV-2 infection among participants was 2%. Surgical mask use as compared to no mask use was associated with a small reduction in risk for infection, but the finding was not statistically significant, the researchers noted. "The study suggests that masks may have small benefits in reducing the risk of infection in the wearer," said the report's lead author, Dr. Roger Chou, a professor in the School of Medicine at the Oregon Health and Sciences University. Unfortunately, Denmark is a place where it would be harder to show benefits because the infection rate there is low and people have been good about following guidelines, such as social distancing and handwashing, Dr. Chou said. "One important reason to wear masks is to prevent those who don't realize they are infected or have mild symptoms from infecting others," Dr. Chou said. "But this study wasn't designed to evaluate that." Of the two other studies, one, which included 16,397 health care workers and first responders, found that use of an N95 or surgical mask all of the time versus not all of the time was associated with a decreased risk for infection. The second study, which included 20,614 asymptomatic health care workers, found that the risk for infection was reduced with any mask use versus no mask use. The update of the living rapid review is important, said Juan Jesus Carrero, a professor of epidemiology in the department of medical epidemiology and statistics at the Karolinska Institute in Stockholm. "In interpreting the results of the DANMASK study, it is essential to remember that it was not a study of source control, and therefore doesn't tell us about the ability of community mask wearing to reduce overall transmission in the pandemic," Carrero said in an email. The new information included in Dr. Chou's study was welcomed by Dr. Catherine Clase, an associate professor in the department of medicine at McMaster University and a member of the Centre of Excellence in Protective Equipment and Materials. "The two additional observational studies on mask wearing are consistent with the expected degree of protection based on the authors' previous work and the meta-analysis on the effects of masks in the transmission of non-COVID coronaviruses," Dr. Clase said in an email. Face Masks Protect Wearers, Others From COVID: Studies 1/6/2021 https://www.medscape.com/viewarticle/943412_print https://www.medscape.com/viewarticle/943412_print 2/2 The Czypionka article highlighted the importance of masking to prevent the spread of COVID-19, Dr. Clase said. "I agree with their assessment that masks can play an important role in reducing the spread of particles of all sizes," she added. Calling the Czypionka article "outstanding," Carrero applauded the authors for pulling together "a network of evidence on the diverse questions which have surrounded mask use since the beginning of the pandemic. As they summarize, universal community masking has been associated with fewer new cases and lower mortality in every study to examine this question." SOURCE: https://bit.ly/2L8l6h3 and https://bit.ly/3n3olDD Annals of Internal Medicine, online December 29, 2020. Reuters Health Information © 2020 Cite this: Face Masks Protect Wearers, Others From COVID: Studies - Medscape - Dec 30, 2020
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