Even before Robert F. Kennedy Jr. took office in February as secretary of the Department of Health and Human Services, some public health experts worried he might use his influence to carry out an anti-vaccine agenda he’d spent decades promoting.
In the worst-case scenario, they said, he might dismiss experts on whom the government relies to make sound decisions about immunizations and enact policies restricting access. He might cancel important research that would be needed in a future pandemic.
In less than six months, Mr. Kennedy has done all that and more.
The health secretary has expressed doubts about childhood vaccines, including those against polio and measles, that have been the mainstay of childhood immunizations for decades. He has described the Covid shot as “the deadliest vaccine ever made.”
Under his leadership, the Food and Drug Administration restricted access to the Covid vaccines for healthy pregnant women and children. And on Tuesday, he canceled nearly $500 million of grants and contracts for work on mRNA vaccines, the technology that helped turn the tide against the coronavirus.
Mr. Kennedy explained his decision in a video on social media, claiming falsely that mRNA vaccines offer no protection against respiratory viruses and can prolong pandemics.
Most scientists were aghast. His assault on mRNA vaccines, and in particular the Covid vaccines developed in the first Trump administration, may have even riled the president.
“Operation Warp Speed was, whether you’re Republican or Democrat, considered one of the most incredible things ever done in this country,” President Trump said at a news briefing on Wednesday in response to a question about mRNA vaccines.
He added that he had scheduled a meeting with Mr. Kennedy on Thursday to discuss the cancellations.
Current and former federal officials, like many scientists, support some aspects of Mr. Kennedy’s Make America Healthy Again agenda. They generally agree with him that ultraprocessed foods, pesticides and food dyes are harmful, and that Americans are facing epidemics of obesity, diabetes and heart disease.
But on immunizations, Mr. Kennedy has left behind the mainstream, siding with the more extreme wing of the anti-vaccine movement.
“I see Secretary Kennedy as having several very positive potential influences,” said Adm. Brett Giroir, a former assistant secretary for health in the first Trump administration who was involved in the development of the Covid vaccines.
Admiral Giroir agrees with Mr. Kennedy that mandates for the Covid vaccine during the pandemic “went too far.”
“But I think most Republicans disagree with the large-scale undermining of vaccines and vaccine confidence, which is what is happening now,” Admiral Giroir added.
“The characterization that Covid vaccines are deadly is completely wrong, and I think just mimics and reiterates his historical bias and fringe science view of vaccines.”
In interviews, nearly a dozen former federal officials, from both Republican and Democratic administrations, and several health experts said they were deeply concerned about the direction of vaccine policy in the United States.
“In the long run, the biggest deal is, once you open this up to political influence, how are we going to get back?” said Dr. Robert Califf, who led the F.D.A. in the Biden administration.
Mr. Kennedy may also be out of step with most Americans. In a recent poll conducted by KFF, a nonpartisan health policy organization, most adults said they were at least “somewhat confident” in the safety of routine vaccines, including those for measles and polio.
And although vaccination rates have fallen since the Covid-19 pandemic began, a vast majority of parents still choose to immunize their children.
Mr. Kennedy’s views on Covid vaccines may find more purchase, however. Roughly one-third of Republicans and independent voters in the survey said the false claim that mRNA vaccines can alter a person’s DNA was either “definitely true” or “probably true.”
His actions against vaccines will only create more confusion for Americans, and especially parents of young children, some experts warned.
“My fear for the future of public health is really much more about this sense of collective confidence that we’ve all had for decades and decades that could really begin to be undermined,” said Daniel Carpenter, a professor at Harvard University who has written extensively about the public’s trust in government.
At the outset of his tenure, it seemed that Mr. Kennedy might not allow his skepticism of vaccines to influence national policy.
In his confirmation hearings, he reassured lawmakers that he would not take away anyone’s vaccines, change the childhood immunization schedule or make changes to the advisory panel that makes recommendations for vaccines.
But Mr. Kennedy has pivoted in recent weeks, with new policy developments announced at a quickening pace.
In June, he fired all 17 members of the expert panel on vaccination and replaced them with eight people whose views on vaccines mostly align with his own. (One later withdrew.)
He incorrectly claimed that the C.D.C.’s scientific advisers had financial conflicts of interest and promised transparency. But his new advisers have not made their own conflicts public.
The advisers have said new work groups at the agency will scrutinize the current immunization schedules for children and adolescents. But representatives of professional organizations like the American Academy of Pediatrics and the Infectious Diseases Society of America — typically deeply involved in discussions — will be excluded.
“It’s always great to ask questions, to have diversity of views, but you do that by adding diversity, not by removing experts,” said Dr. Jesse Goodman, who served in senior leadership roles at the F.D.A. under President George W. Bush and President Bill Clinton.
Mr. Kennedy has also hired stalwarts of the anti-vaccine movement, such as Lyn Redwood, a former leader of Children’s Health Defense, to the health department.
At a meeting of the new advisers, Ms. Redwood claimed that a preservative added to some flu vaccines was dangerous and toxic to children. Based on her inaccurate presentation, the panel voted to rescind recommendations for certain flu vaccines, a move Mr. Kennedy later endorsed.
“What we’re seeing is disdain of experts, and belief that they know the right way to do everything,” said Dr. Janet Woodcock, who led the F.D.A. when the Covid vaccines were first rolled out.
“It won’t end well,” she added, referring to the effect on the health of Americans, and particularly children: “There’s going to be bodies in the street before it’s all over.”
MRNA vaccines have been a target of Mr. Kennedy for years now. They were developed too quickly, he and other critics have said, claiming falsely that the vaccines caused huge numbers of adverse reactions and deaths, despite evidence that they saved millions of lives.
In May 2021, in the thick of the pandemic, he filed a petition with the F.D.A. demanding that the agency revoke authorization for the shots. He has not done that yet as health secretary.
But in May, he announced that the Covid vaccines would no longer be recommended for healthy children or healthy pregnant women. (The C.D.C. later said children could receive the vaccine if a doctor agreed it was needed.)
The decision upended decades of protocol: It was made without the knowledge or approval of the C.D.C. or its vaccine advisers and announced in a video on social media.
“Making decisions yourself is a high-wire act,” said Dr. David Kessler, who led the F.D.A. for more than six years under President George H.W. Bush and President Bill Clinton. “No one person is going to have all the expertise that’s necessary.”
In May, the F.D.A. announced a new policy requiring additional studies before the agency would approve mRNA Covid shots for healthy Americans younger than 65.
The policy had been developed only by the agency’s commissioner, Dr. Marty Makary, and Dr. Vinay Prasad — who had been appointed to lead the F.D.A.’s vaccine division — overruling dozens of staff experts and sidestepping the agency’s outside advisers.
(Dr. Prasad recently exited the F.D.A. after conservative influencers like Laura Loomer turned on him.)
Legally, the decision could be challenged as being “arbitrary and capricious,” according to some observers. But former F.D.A. officials were more alarmed by the bypassing of experts and lack of transparency.
“The F.D.A. shows its work — that’s why people trust the decisions the agency makes,” said Dr. Joshua Sharfstein, a former principal deputy commissioner at the agency.
“There’s something fundamentally strange about this that goes beyond the actual decision,” he said. “If it can be done this way for Covid vaccines, what’s next?”
In May, Mr. Kennedy revoked a nearly $600 million contract to develop an mRNA vaccine against bird flu, which many scientists fear will cause the next pandemic. His latest move, canceling work on mRNA vaccines being developed to prepare for future outbreaks, has led to widespread consternation.
“It should not be underestimated how much this will set things back,” said Scott Hensley, an immunologist at the University of Pennsylvania.
While the cuts do not affect his work, “I don’t want to have to worry about my kids getting H5N1 infection in the case of a pandemic,” he said, referring to the bird flu virus.
If Mr. Kennedy has safety concerns about mRNA, he added, federal health officials should work to resolve those problems before a pandemic hits.
Other countries, including China, Canada and South Korea, are embracing the technology. In Australia, Dr. Sharon Lewin, director of the Doherty Institute at the University of Melbourne, is using government funds to explore whether mRNA can help rid the body of H.I.V.
Mr. Kennedy’s decision is “a grave step backward to poorer, less effective vaccines,” she said.
Some American companies are developing mRNA vaccines for diseases including cancer, Type 1 diabetes and multiple sclerosis. The cuts do not directly affect that work, but experts fear they will have a chilling effect nonetheless.
“If a policy might change without advance notice, it makes it very difficult for the companies to commit to develop products, including vaccines,” said Dr. Philip Krause, who worked at the agency for 30 years and resigned in protest of a vaccine policy during the Biden administration.
Dr. Krause has already seen early evidence, he said, that investors are wary of sinking money into vaccine and treatment projects that may abruptly be terminated.
The administration’s treatment of mRNA vaccines, and Covid vaccines in particular, seemed motivated more by revenge for pandemic policies than by genuine concerns, some former officials said.
“This is pseudoscience, and this is retaliation,” said Dr. Woodcock, the former F.D.A. official. “I don’t know how long this can persist, because it’s not a policy, it’s not a scientific position.”