Top FDA vaccine regulator Peter Marks pushed out

David Lim, Adam Cancryn and Lauren Gardner
March 29, 2025

Top FDA vaccine regulator Peter Marks abruptly resigned on Friday, according to a copy of his resignation letter obtained by POLITICO.

Marks was pushed out under pressure from HHS Secretary Robert F. Kennedy Jr., said two people familiar with the matter granted anonymity to discuss the resignation — a development that sent shockwaves across the nation’s capital and prompted concern among some pharmaceutical companies.

Kennedy and his team decided in recent weeks to push Marks out, concluding that they needed a fresh start as part of the department’s broader reorganization, said one person familiar with Kennedy’s thinking granted anonymity to discuss the situation. The person denied that there was a single flashpoint that prompted Marks’ departure.

But Marks had grown increasingly concerned by Kennedy’s attitude toward vaccines, said another person familiar with the matter, and was at odds with the HHS secretary in particular over his tepid response to the Texas measles outbreak.

In his resignation letter, Marks directly confronted vaccine hesitancy and the ongoing measles outbreak in West Texas that has been implicated in two deaths and hundreds of cases of the viral illness, which was declared eradicated from the U.S. in 2000. Kennedy has made public statements tepidly supporting measles, mumps and rubella vaccines while promoting alternative treatments like vitamin A that public health experts widely agree are no substitute for the protection offered by vaccines.

“Undermining confidence in well-established vaccines that have met the high standards for quality, safety, and effectiveness that have been in place for decades at FDA is irresponsible, detrimental to public health, and a clear danger to our nation’s health, safety and security,” Marks wrote in the letter addressed to acting FDA Commissioner Sara Brenner and obtained by POLITICO. Marks’ final day at the FDA is April 5.

“Efforts currently being advanced by some on the adverse health effects of vaccination are concerning,” Marks wrote. “The history of the potential individual and societal benefits of vaccination is as old as our great nation.”

In a statement to POLITICO, an HHS official said, “If Peter Marks does not want to get behind restoring science to its golden standard and promoting radical transparency, then he has no place at FDA under the strong leadership of Secretary Kennedy.”

The departure of Marks — who joined the FDA in 2012 as the deputy director of the Center for Biologics Evaluation and Research — leaves the agency without yet another senior regulator. The agency’s top drug regulator, Patrizia Cavazzoni, left shortly before President Donald Trump took office, and its longtime top device regulator, Jeff Shuren, left the agency last year.

Marks played a leading role in Operation Warp Speed, the effort during Trump’s first term to develop and deploy a Covid-19 vaccine during the pandemic’s earliest months.

“Have had two CEOs call me already,” texted a Republican pharmaceutical lobbyist granted anonymity to discuss the Marks departure. “Folks are VERY concerned. This is why [Sen. Bill] Cassidy should have voted NO.”

In his letter, Marks said he was “willing to work to address the Secretary’s concerns regarding vaccine safety and transparency,” planning to hold a series of public meetings with the National Academy of Sciences, Engineering and Medicine — one of the nation’s preeminent scientific institutions.

“However, it has become clear that truth and transparency are not desired by the Secretary, but rather he wishes subservient confirmation of his misinformation and lies,” Marks wrote.

On Friday, a day after HHS announced 3,500 employees would be fired at the agency, FDA employees arrived at their offices in White Oak, Maryland, to find armored vehicles from the Department of Homeland Security out front and more security personnel at the door than usual, according to two FDA employees granted anonymity to discuss the impact on the FDA headquarters.

Later that day, employees were told, via an email reviewed by POLITICO, that the FDA would be discontinuing use of an overflow parking lot set up to accommodate the glut of people coming into the office after the department dashed work-from-home arrangements.

“My hope is that during the coming years, the unprecedented assault on scientific truth that has adversely impacted public health in our nation comes to an end so that the citizens of our country can fully benefit from the breadth of advances in medical science,” Marks wrote.

Ruth Reader contributed to this report.