The Meals and Drug Administration’s prime vaccine official, Dr. Peter Marks, resigned underneath strain Friday and mentioned that Well being Secretary Robert F. Kennedy Jr.’s aggressive stance on vaccines was irresponsible and posed a hazard to the general public.

“It has turn out to be clear that reality and transparency are usually not desired by the secretary, however slightly he needs subservient affirmation of his misinformation and lies,” Dr. Marks wrote to Sara Brenner, the company’s performing commissioner. He reiterated the emotions in an interview, saying: “This man doesn’t care in regards to the reality. He cares about what’s making him followers.”

Dr. Marks resigned after he was summoned to the Division of Well being and Human Providers Friday afternoon and instructed that he might both stop or be fired, based on an individual accustomed to the matter.

Dr. Marks led the company’s Heart for Biologics Analysis and Analysis, which approved and monitored the protection of vaccines and a wide selection of different therapies, together with cell and gene therapies. He was seen as a gradual hand by many through the Covid pandemic however had come underneath criticism for being overly beneficiant to corporations that sought approvals for therapies with blended proof of a profit.

His continued oversight of the F.D.A.’s vaccine program clearly put him at odds with the brand new well being secretary. Since Mr. Kennedy was sworn in on Feb. 13, he has issued a sequence of directives on vaccine coverage which have signaled his willingness to unravel a long time of vaccine security insurance policies. He has rattled individuals who worry he’ll use his highly effective authorities authority to additional his decades-long marketing campaign of claiming that vaccines are singularly dangerous, regardless of huge proof of their function in saving tens of millions of lives worldwide.

“Undermining confidence in well-established vaccines which have met the excessive requirements for high quality, security and effectiveness which were in place for many years at F.D.A. is irresponsible, detrimental to public well being, and a transparent hazard to our nation’s well being, security and safety,” Dr. Marks wrote.

Mr. Kennedy has, for instance, promoted the worth of vitamin A as a therapy through the main measles outbreak in Texas whereas downplaying the worth of vaccines. He has put in an analyst with deep ties to the anti-vaccine motion to work on a research inspecting the long-debunked principle that vaccines are linked to autism.

And on Thursday, Mr. Kennedy mentioned on NewsNation that he deliberate to create a vaccine damage company inside the Facilities for Illness Management and Prevention. He mentioned the trouble was a precedence for him and would assist convey “gold-standard science” to the federal authorities.

The Home Committee on Oversight and Authorities Reform despatched an inventory of calls for to Mr. Kennedy on Saturday, searching for information associated to an inventory of actions it described as “endangering the nation’s public well being by undermining routine vaccinations.” The committee requested him to offer information by April 14 associated to Dr. Marks’s termination.

The letter, signed by Gerald E. Connolly, a Democrat of Virginia and the rating member of the committee, additionally urged the F.D.A. to return funding to grants associated to vaccine hesitancy and use and supply details about canceled or delayed vaccine-related advisory committee conferences. “I’m deeply alarmed that you simply proceed to sow doubts concerning the efficacy of vaccination,” the letter mentioned.

An H.H.S. spokesman mentioned in a press release Friday evening that Dr. Marks had no place on the F.D.A. if he was not dedicated to transparency.

In his letter, Dr. Marks talked about the lethal toll of measles in gentle of Mr. Kennedy’s tepid recommendation on the necessity for immunization through the outbreak amongst many unvaccinated individuals in Texas and different states.

Dr. Marks wrote that measles, “which killed greater than 100,000 unvaccinated kids final 12 months in Africa and Asia,” due to problems, “had been eradicated from our shores” by way of the widespread availability of vaccines.

Dr. Marks added that he had been prepared to deal with Mr. Kennedy’s issues about vaccine security and transparency with public conferences and by working with the Nationwide Academies of Sciences, Engineering and Drugs, however was rebuffed.

“I did all the pieces I presumably might for this administration to work with them in an effort to revive confidence in vaccines,” Dr. Marks mentioned within the interview. “It grew to become clear that’s not what they wished.”

Leaving the F.D.A., Dr. Marks added, was a “weight lifted from me, as a result of I used to be in an setting the place it was spiraling deeper and deeper into hazard.”

Ellen V. Sigal, founding father of the advocacy group Associates of Most cancers Analysis and an in depth ally of Dr. Marks’s, mentioned his “management has been instrumental in driving medical innovation and guaranteeing that lifesaving therapies attain sufferers who want them most.” His departure, she mentioned, “will create a major void.”

John Crowley, the chief government of the Biotechnology Innovation Group, the biotechnology business’s commerce affiliation, additionally praised Dr. Marks’s management and added a warning about the way forward for the company: “We’re deeply involved that the lack of skilled management on the F.D.A. will erode scientific requirements and broadly impression the event of recent, transformative therapies to struggle ailments for the American individuals,” he mentioned in a press release on Saturday.

Dr. Marks steered the F.D.A.’s vaccine program through the tumultuous years of the coronavirus pandemic, guiding the company and its exterior advisers by way of quite a few choices in regards to the type of proof wanted to grant emergency authorization for the vaccines produced underneath the Trump administration’s Operation Warp Pace initiative, which Dr. Marks helped begin up.

In June 2022, he pleaded with a committee of outdoor specialists to think about the hazard the virus posed to kids youthful than 5; the panel voted later that day to suggest vaccines for that age group.

“We’ve got to watch out that we don’t turn out to be numb to the variety of pediatric deaths due to the overwhelming variety of older deaths right here,” Dr. Marks mentioned on the time.

Dr. Peter Hotez, a vaccine knowledgeable from Baylor Faculty of Drugs, mentioned he had spoken with Dr. Marks often through the pandemic. “He was terribly dedicated to utilizing science to assist the American individuals,” he mentioned. “He was one of many heroes of the pandemic, so I’m sorry to see him go.”

Dr. Marks was seen skeptically by some on the F.D.A., together with former members of his personal vaccine staff. The 2 most senior regulators within the company’s vaccine workplace resigned in 2021 partly due to a Biden administration effort to expedite the licensing of Pfizer’s coronavirus shot and the authorization of Covid booster pictures.

Whereas Mr. Kennedy has been urgent for extra research of vaccine accidents, Dr. Michael Osterholm, director of the Heart for Infectious Illness Analysis and Coverage on the College of Minnesota, mentioned such analysis had already been a precedence for many years.

“I worry this can be a strategy to emphasize vaccine accidents in a means that’s fully disproportionate to what the actual danger is,” he mentioned.

Dr. Marks clearly shared these issues. In his letter, he expressed a want that injury brought on by the present administration be restricted.

“My hope,” he wrote, “is that through the coming years, the unprecedented assault on scientific reality that has adversely impacted public well being in our nation involves an finish in order that the residents of our nation can totally profit from the breadth of advances in medical science.”