The Food and Drug Administration’s recent activities regarding Covid-19 vaccines stray far from the well-established standards of vaccine regulatory processes.
The first sign of trouble was the failure to rule on the licensure of the Novavax protein-based Covid-19 vaccine by the established deadline of April 1. This should have been a standard review timeline given the extensive efficacy and safety data obtained through large randomized placebo-controlled clinical trials conducted during the pandemic. However, the ruling was delayed until May 19, when the vaccine was approved only for use in “adults 65 years and older and in individuals 12 through 64 years of age with at least one underlying high risk medical condition for severe outcomes from COVID-19.”
This same vaccine had been previously given to hundreds of thousands, if not millions, of individuals, but with this ruling, the FDA restricted its use. This ruling was likewise counter to the usual approval process in which vaccines are licensed by the FDA, while recommendations for their use are made by the Advisory Committee on Immunization Practices (ACIP), an advisory committee to the Centers for Disease Control and Prevention. (I am a former ACIP member.)
On May 20, an article written by Vinay Prasad and Marty Makary of the FDA titled “An Evidence-Based Approach to Covid-19 Vaccination” appeared in the New England Journal of Medicine outlining the changes in how the FDA would evaluate Covid-19 vaccines in the future. It sets out new guidelines for specific groups that are recommended to receive the vaccine and additional clinical trials that will be required for continued licensure of Covid-19 vaccines.
On the same day, at a town hall meeting, Prasad discussed the NEJM article and outlined FDA requirements for the licensure of future Covid-19 vaccines. A dialogue then followed with Prasad and Makary discussing the rationale for these changes.
This decision-making was in stark contrast to the standard practice whereby the FDA provides guidelines for product licensure. The usual practice is to provide Draft Guidance Documents, comprehensively outlining specific requirements in the Federal Register, and inviting a period of public comment so experts in a broad range of fields, including immunology, biostatistics, and clinical care, can add their perspectives. Then the FDA finalizes the document and posts it to the FDA website.
The FDA guidance presented in the NEJM was not released in the Federal Register, did not invite comment, and provided only a general outline for Covid-19 vaccine licensure. The report lacked detail, and a clear blueprint was not provided. Many questions were left unanswered. Why will only healthy individuals 50-64 years of age be included in the required placebo-controlled randomized clinical trials? Given the current burden of Covid-19, what are the projected numbers of individuals needed for the required clinical trials to demonstrate at least 30% efficacy? Why recommend additional studies of six months of follow-up to assess duration of protection when it has already been repeatedly shown that Covid-19 vaccine protection wanes?
Why are studies to determine vaccine response required with new Covid-19 vaccines when all previous changes in Covid-19 vaccines have been shown to stimulate immunity? What are the safety studies that are mentioned and what will be the required sample sizes? Certainly, the safety assessment of millions and billions of doses of Covid-19 vaccines should be adequate. These additional required trials will be expensive and will likely increase the vaccine cost, while the FDA restrictions will also likely hinder coverage by insurance or public funding for individuals without high-risk conditions.
Restricting Covid-19 vaccine use in healthy children is also concerning and outside of the FDA mandate. The FDA mandate is to ensure safe and effective vaccines based on the clinical studies performed but not to develop specific recommendations for their use. Providing recommendations on vaccine use for the civilian population is the mandate of the ACIP.
The usual sequence is that the vaccines are licensed by the FDA, and then the ACIP issues guidance based on a defined set of considerations. Previously healthy children without high-risk conditions have died from Covid-19, and the vaccines have been shown to be safe and effective in this population. As with any vaccine, as the risk of a disease changes, the risk-benefit is reassessed, and ACIP recommendations may change. The ACIP had planned such a reassessment at their June 2025 meeting. Why does the Health and Human Services secretary say that parents can decide whether they want to give their children an MMR vaccine, a vaccine proven safe and highly effective, but the FDA restricts access to Covid-19 vaccines? Parents should be able to decide, after discussions with their provider, whether they would like their children to receive Covid-19 vaccine.
Extensive data were collected on the safety and effectiveness of the Covid vaccines during the pandemic, some of the most extensive data ever collected for any vaccine. None of the data was reviewed or even acknowledged in the NEJM document. In addition, there is no precedent for mandating continued placebo-controlled randomized clinical trials for vaccines that have already been licensed.
In the dialogue that followed the town hall, Prasad stated that he had written the NEJM document, and I inferred from his comments that no additional input was sought from the experienced FDA staff or other authorities who have been evaluating the effectiveness of the Covid vaccines and other vaccines for years. Prasad and Makary also stated that the Vaccines and Related Biological Products Advisory Committee meeting was scheduled in two days, but did not state that it would be used to ask the skilled members of the committee about the plan. What a lost opportunity. They attributed “vaccine hesitancy” to concern about Covid-19 vaccines, but did not mention the role the secretary of HHS has had in hesitancy by not endorsing the MMR vaccine, even in the face of a national outbreak of measles. It was heartening that the NEJM article did stress that MMR vaccine was highly effective, and that Prasad and Makary supported its use.
The FDA has gone around the well-established procedures for development of guidelines, ignored existing data, and circumvented the role of the ACIP, even though the last ACIP meeting indicated that the recommendations for Covid-19 vaccine use would be re-evaluated in June. Two people with limited expertise in vaccinology are leading the FDA vaccine evaluation process and have decided to dictate what vaccine policy will be with minimal input from experts in the field, no attention to existing data, and little respect for the well-established processes that have served the country well for decades and made the U.S. the envy of vaccine assessment programs throughout the world.
Kathryn M. Edwards, M.D., is a retired vaccinologist and pediatrician and former member of the VRBPAC and ACIP Advisory Committees.
