Vaccine makers were hit particularly hard yesterday, as Marks’ resignation letter alluded to disagreements with HHS Secretary Robert F. Kennedy Jr. on vaccines. Moderna’s stock dropped 9%, while Vaxcyte’s plummeted 46% (though shares of Vaxcyte were also affected by disappointing results of a vaccine candidate.)

As the FDA wavers from cuts, changes and departures under the second Trump administration, another vital figure of the agency is heading for the exit. | In resigning as director of the FDA’s Center for Biologics Evaluation and Research,

Marks offered his resignation while citing Kennedy’s “misinformation and lies” and an “unprecedented assault on scientific truth” impacting public health.

Dr. Peter Marks, the top vaccine official at the Food and Drug Administration, wrote in a letter that he was resigning from his position.

It's not yet been a week since Marty Makary, M.D., was confirmed to lead the FDA as its commissioner. | Peter Marks, M.D., Ph.D., a target for RFK Jr. and allies, last week turned in his resignation as director of the FDA's Center for Biologics Evaluation and Research.

Steele, who joined the FDA in 2022, was previously senior adviser at the Center for Biologics Evaluation and Research, which regulates biological and related products including blood, vaccines, allergenics, tissues, and cellular and gene therapies.