Officials at the Food and Drug Administration have blocked publication of two studies supporting the safety of widely used vaccines against Covid-19 and other safety studies on shingles in recent months, a spokesperson at the US Department of Health and Human Services confirmed.

In October, 2025 FDA scientists were directed to withdraw two Covid-19 vaccine studies that had been accepted for publication in medical journals, the New York Times reported on Tuesday. Then in February, top F.D.A. officials refused to sign off on the submission of abstracts of studies of Shingrix, a shingles vaccine, to a major drug safety conference,

The withdrawn FDA studies on COVID vaccines involved the use of massive 2023 and 2024 vaccine data sets by agency scientists, compiled and analyzed with outside data firms. Pre-prints and abstracts of the studies that have been made public have largely confirmed the vaccines’ safety.

One study, which examined the Covid vaccine in people older than 65, was posted on the prestigious preprint server Medrxiv.org. The study reviewed the records of about 7.5 million Medicare beneficiaries who got the vaccine, in the first six weeks after their jab. Among 14 health outcomes potentially caused by the vaccine, including heart attacks, strokes and Guillain-Barré syndrome (an auto-immune disorder), researchers found only outcome of concern, anaphylaxis, a severe allergic reaction affecting about 1 in a million people to get the Pfizer COVID vaccine.

“No other statistically significant elevations in risk were observed,” the researchers reported. The study was withdrawn under pressure from FDA officials after it had been accepted by the peer reviewed journal Drug Safety, according to the New York Times report.

An abstract of a second COVID safety study was published at the August 2025 conference of the International Society of Pharmacoepidemiology (ISPE), where it remains online. The study monitored the safety of three leading COVID-19 vaccines, produced by Pfizer-BioNTech, Moderna, and Novavax, among individuals aged 6 months–64 years who received the shots in 2023-24. The researchers found evidence of rare, adverse events, previously reported, primarily fever-related seizures and myocarditis (inflammation of the heart muscle). But no new elevated risks were identified among the 4.2 million vaccine recipients analyzed.

“Given the available evidence, F.D.A. continues to conclude the benefits of vaccination outweigh the risks,” the study’s abstract concludes. Withdrawal of that FDA study from submission to the peer-reviewed journal, Vaccine, was first reported by STAT News.

Shingrix vaccine study also blocked by FDA – outside of agency’s purview

In the case of the Shingrix vaccine against shingles, FDA officials in February failed to sign off for scientific staff to submit abstracts on two studies to a drug safety conference. One study found the vaccine’s efficacy to be in line with findings from the clinical trials done before agency approval. A second safety study also aligned with what was known, finding an elevated but low risk for Guillain-Barré syndrome, an autoimmune disease already noted in the vaccine’s label, the New York Times reported.

Asked about the withdrawal of the Covid vaccine safety studies, Andrew Nixon, a spokesman for the Department of Health and Human Services, was quoted saying: “The studies were withdrawn because the authors drew broad conclusions that were not supported by the underlying data. The F.D.A. acted to protect the integrity of its scientific process and ensure that any work associated with the agency meets its high standards.”

Regarding the blocked shingles vaccine research, he said, “The design of that study fell outside the agency’s purview.”

A senior administration official told the New York Times that the decisions about the research had not reached Dr. Marty Makary, the F.D.A. commissioner, or Health Secretary Robert F. Kennedy Jr. Dr. Vinay Prasad, head of the FDA. vaccine office at the time, did not respond to requests for comment.

In recent weeks, Dr. Jay Bhattacharya, who was serving as interim leader of the US Centers for Disease Control and Prevention (CDC) also canceled the publication of a report concluding that the COVID vaccine sharply cut the odds of hospitalizations and emergency room visits last winter, claiming that the study had limitations.

The current US Administration, under the leadership of HHS Secretary Robert F Kennedy Jr, has dramatically cut research funding for vaccine development and cast doubt on multiple aspects of vaccine effectiveness and safety. It has also frozen vaccine funding to Gavi, the Vaccine Alliance, over alleged safety issues related to the use of thimerosal, as a preservative in some vaccines most often used in low- and middle-income countries where cold chain remains a problem. Those are concerns that WHO and other leading vaccine experts have long said are resolved. See related story here:

https://healthpolicy-watch.news/us-freezes-all-funds-to-gavi-over-vaccine-preservative-thimerosal/

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