FDA blocks publication of studies finding Covid, shingles vaccines safe

The Food and Drug Administration blocked the release of studies built on millions of patient records that found serious side effects from Covid and shingles vaccines were very rare, a move that puts scientific transparency and vaccine confidence at the center of a new fight inside the federal health apparatus.

According to reporting published May 5, FDA scientists were told in October 2025 to withdraw two Covid vaccine studies that had already been accepted for publication in medical journals. In February 2026, top FDA officials also did not sign off on submitting Shingrix abstracts to a major drug-safety conference, extending the halt from journal publication to the conference circuit. The studies were carried out with help from data firms and reviewed millions of patient records.

Andrew Nixon, the HHS spokesman, said the studies were pulled because their authors drew broad conclusions not supported by the underlying data. The department said the FDA acted to protect the integrity of its scientific process and ensure that work tied to the agency met its standards. The decision landed amid a broader Trump administration and HHS push that has included softened Covid shot recommendations, part of a pattern that critics say narrows vaccine access and muddies the government’s message.

The clash comes after another blocked CDC analysis reportedly found that winter Covid shots cut emergency room and urgent-care visits by about 50% and hospitalization risk by about 55% among healthy adults, a report that had been scheduled for the Morbidity and Mortality Weekly Report. The FDA has also said it monitors authorized Covid vaccines through passive and active safety surveillance systems, underscoring the tension between internal review and public disclosure at a time when health agencies are already under pressure to rebuild trust.