The Food and Drug Administration has blocked the publication of several completed safety studies on COVID-19 and shingles vaccines, a decision confirmed by the Department of Health and Human Services and first reported by The New York Times.
Two COVID-19 vaccine safety studies that had already been accepted by medical journals were withdrawn in October 2025 before they could be published, according to a report by Healthline. The FDA also declined to approve two additional safety studies on the shingles vaccine Shingrix, which required federal sign-off before they could be submitted to a drug safety conference. All of the studies were conducted by FDA scientists and data contractors and involved millions of patient records funded by taxpayer dollars.
An HHS spokesperson told The New York Times that the studies were blocked due to concerns about their conclusions. HHS did not respond to further requests for comment.
Medical experts pushed back on that explanation. "Scientists and physicians aren't buying that explanation," said Robert Glatter, MD, attending physician in the Department of Emergency Medicine at Lenox Hill Hospital in New York City, and assistant professor of Emergency Medicine at Zucker School of Medicine at Hofstra/Northwell. "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," Glatter told Healthline.
Monica Gandhi, MD, MPH, a professor of medicine at the University of California, San Francisco, said the timing was particularly problematic for public confidence. "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," she said.
William Schaffner, MD, professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center in Nashville, stressed the value of open access to the data. "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," he said.
Some experts told Healthline they believe the decision may reflect the influence of HHS Secretary Robert F. Kennedy Jr., who has a documented history of skepticism toward vaccines. Both the COVID-19 vaccines and Shingrix carry substantial bodies of existing evidence supporting their safety and effectiveness, according to Healthline.
The withdrawal of the studies comes at a moment when public trust in vaccine safety information is already strained. Researchers and physicians who spoke with Healthline said the lack of transparency around the decision makes the situation more difficult to navigate for both clinicians and patients. No timeline has been given for when, or whether, the blocked studies might be released.
