When President-elect Donald Trump said he would nominate Robert F Kennedy Jr, one of the nation’s most prominent leaders of the anti-vaccine movement, to lead the Department of Health and Human Services, some social media users warned him Americans to update their vaccines.

“IMPORTANT – vaccines may now be BANNED for part of this winter by Trump and RFK Jr, although we hope any such ban will be stopped by a court order,” read a Nov. 15 post on social app Threads. “GET YOUR VACCINATIONS NOW – just in case.”

For two decades, RFK Jr repeated false and misleading claims about science and public health. His failed presidential campaign of conspiracy theories earned him PolitiFact’s 2023 Lie of the Year. Kennedy, the grandson of Democratic President John F Kennedy and the son of former presidential candidate Senator Robert Kennedy Sr of New York, ran as an independent before suspending his campaign in August and endorsing Trump.

Scientists have sounded the alarm about Trump’s decision to call on RFK Jr. There are 13 agencies housed in that department, including the US Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA), and the National Institutes of Health (NIH). .

“The outlook is cloudy”

Scientists were far from alone in expressing concern about what Kennedy might do as Secretary of Health and Human Services.

“Serious question – can he ban vaccines?” a Threads user asked on November 14th. “For example, if I want to get a COVID-19 and flu shot next year, might they not be available?”

The outlook is murky, in part because no one can be sure what RFK Jr. will do. On Nov. 6, before Trump officially nominated him for the seat, Kennedy told an NBC News reporter, “If vaccines work for somebody, I’m not going to take them.”

Experts on vaccine law and policy told PolitiFact that Kennedy cannot unilaterally ban vaccines and that any effort to ban vaccines will likely face a legal battle. But RFK Jr could further reduce how accessible they are to Americans, they said. And part of its power rests on the fact that the Trump administration can win buy-in from other lawmakers and public health leaders, some of whom Trump might also call.

Wendy Parmet, a law professor at Northeastern University and director of the law school’s Center for Health Law and Policy, said RFK Jr. cannot ban vaccines “by fiat,” or with a single order or decree.

He could, however, “start the FDA’s process of reexamining vaccine safety and move to revoke or place restrictions on some vaccine approvals,” she said. “But that would take time and would undoubtedly be challenged in court.”

There are limits to the level of control the Health and Human Services secretary has over vaccines, Parmet said. But if confirmed, RFK Jr would “control the people who control the agencies that have a lot of authority over vaccines,” she added.

He could get those people to act to limit access by revoking vaccine licenses or directing the CDC to change its vaccine messaging and recommendations, which would affect insurance and medical practice, Parmet said.

Still, “there is no authority to ban vaccines as a group nationwide,” she said. “It would take an act of Congress for that.”

“Procedural Requirements”

Dorit Reiss, an expert on vaccine law and policy at the University of California, San Francisco, told PolitiFact that federal regulations dictate how approved vaccines are taken off the market.

“You have to meet the procedural requirements and show that the removal was not arbitrary and capricious,” she said. “And the main player in that is the FDA commissioner, not the secretary, and we don’t know who that will be” or if he would be “still sympathetic to the idea.”

The regulations say the FDA commissioner — whom Trump would also appoint — could begin the process of revoking the license if the commissioner finds that “the licensed product is not safe and effective for all intended uses.”

For years, RFK Jr’s refrain has been that vaccines are unsafe. In July 2023, he told a podcaster that some vaccines “probably prevent more problems than they cause,” but in the same breath claimed, “There’s no vaccine that’s, you know, safe and effective.”

After notifying the manufacturer of the agency’s plan to revoke a vaccine license, the FDA commissioner would have to hold a hearing and also give the manufacturer a “reasonable” amount of time to comply with whatever the government asked them to do.

“Manufacturers can sue if they don’t agree,” said Reiss of the University of California. “If there is not sufficient justification, (they) can win in court against the revocation.”

Kennedy could make vaccines less affordable

Reiss said it’s easier to stop approval of new vaccines than to revoke access to existing vaccines, but it would take an FDA commissioner receptive to the idea.

She added that as secretary, JFK Jr could, for example, rescind emergency use authorizations for children’s COVID-19 vaccinations, which would result in children under 12 losing access to those vaccines.

He could also appoint or remove members of federal advisory committees, including the Advisory Committee on Immunization Practices, which recommends vaccines that the CDC reviews and adopts. He could fill the committee with people who have anti-vaccination beliefs who could then overturn vaccination recommendations, Reiss said.

Parmet said the vaccination recommendations adopted by the CDC determine vaccines “covered at no charge” under the Affordable Care Act and immunizations available under the Vaccines for Children program, which provides vaccines to Medicaid-enrolled and uninsured children.

JFK Jr could undermine grant programs that support state and local immunization, such as the CDC’s Section 317 Immunization Program, a reference to Section 317 of the Public Health Service Act.

The program aims to ensure that children and adults are immunized by providing federal funds to state and local public health agencies to support vaccine purchases and operating costs, said the 317 Coalition, a nonprofit vaccine advocacy organization. His 2023 report to Congress said most of the program’s funding supports the mandatory Vaccines for Children program.

The Pennsylvania Department of Health says the program “plays a critical role in achieving national goals for immunization coverage and disease reduction.” The Oklahoma State Department of Health has described the program as “a valuable national resource” that provides routine vaccinations for the uninsured and responds to vaccine-preventable disease outbreaks.

Even without changes to official vaccination recommendations, Parmet said “informal changes” in the CDC’s recommendations could change parents’ willingness to vaccinate their children, influence states’ vaccination recommendations and affect the practice of some pediatricians.

“In other words, by simply changing the text on its website,” the CDC could “discourage or reduce the use of the vaccine,” she said.

Legal challenges, industry pushback

If Kennedy’s agency tried to enact a nationwide ban without any action from Congress, the effort would likely face successful legal challenges, Parmet said.

It’s unclear whether a vaccine ban will win congressional support, but anti-vaccine lawmakers have made gains state-by-state in recent years, passing legislation that eliminates vaccination requirements for homeschooled children or preemptively prohibits schools from requiring students to receive COVID-19 vaccines.

JFK Jr could also start the FDA reexamining vaccine safety and move to revoke or restrict some vaccine approvals. But those actions “would take time and will undoubtedly be challenged in court,” Parmet said.

Reiss of the University of California said existing laws and regulations could constrain JFK Jr.

“He can’t violate express statutory provisions unless they change, and he has to contend with other agency heads,” such as the people in charge of the CDC and the FDA, she said.

Just as he will appoint the Secretary of Health and Human Services and the commissioner of the FDA, Trump will appoint the commissioners of the CDC and the National Institutes of Health. In 2025, all of these roles will need Senate approval, and the Senate will have a Republican majority in January. Trump has not announced his picks for these jobs since Nov. 20.

Kennedy could “certainly try to convince these people, and there is some interdependence — they need the secretary to pass rules and appoint people to advisory committees,” Reiss said. “But it’s the president who has the power of impeachment over them, not the secretary.”

Pharmaceutical companies are also likely to resist by lobbying against efforts to ban vaccines and suing the government, Reiss said.

PolitiFact researcher Caryn Baird contributed to this report.