FDA Blocks Key Vaccine Safety Studies: Experts Warn of Public Health Risks

The U.S. Food and Drug Administration (FDA) has blocked the publication of safety studies for both COVID-19 and shingles vaccines, citing concerns over their conclusions. The decision has sparked criticism from public health experts who argue that the move undermines transparency and could erode public trust in vaccines.

The Department of Health and Human Services (HHS), which oversees the FDA, confirmed the decision, first reported by The New York Times. The studies in question involved millions of patient records and were conducted using taxpayer-funded resources. However, the FDA blocked their publication before they could reach the public.

Two studies on COVID-19 vaccines that had been accepted by medical journals were withdrawn in October 2025 before publication. Additionally, the FDA failed to approve two safety studies on the shingles vaccine Shingrix, which required federal approval prior to submission to a drug safety conference.

An HHS spokesperson told The New York Times that the studies were blocked due to concerns about their conclusions. However, experts have dismissed this explanation as insufficient.

“Scientists and physicians aren’t buying that explanation. The public health implications of blocking such studies are serious … secrecy can backfire. People who are already distrustful may see suppression where officials see caution.”

— Robert Glatter, MD, attending physician in the Department of Emergency Medicine at Lenox Hill Hospital, New York City

Both COVID-19 and shingles vaccines have extensive evidence supporting their safety and effectiveness. Experts argue that blocking these studies could undermine public confidence in vaccines at a time when misinformation is already widespread.

“The COVID-19 vaccine safety studies had been peer reviewed and would have been extremely important to be published for reassurance of the public of the safety of these vaccines.”

— Monica Gandhi, MD, MPH, professor of medicine at the University of California, San Francisco

“Both vaccines are in widespread use, not only here in the United States, but around the world. Having these data available so that professional people can look at them and make their own assessments when they see the data is very important.”

— William Schaffner, MD, professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center

The FDA’s decision has raised questions about the potential influence of political agendas. Some experts suggest that the move may be tied to the anti-vaccine stance of HHS Secretary Robert F. Kennedy Jr., though no direct evidence has been provided.

Public health advocates emphasize the importance of transparency in vaccine research, particularly as vaccine hesitancy continues to pose challenges to global health efforts.