With two extraordinary moves, Health Secretary Robert F. Kennedy Jr. has upended the certainty that American children will always have cost-free access to lifesaving vaccines.

For decades, a little-known scientific panel at the Centers for Disease Control and Prevention has recommended which shots Americans should get and when. The group’s endorsement means insurance companies must cover the costs and helps states decide which vaccines to mandate for school-age children.

The panel, the Advisory Committee on Immunization Practices, also determines which shots are provided for free through the Vaccines for Children program, which serves about half of the children in the United States.

Panel members fired

On Monday, Kennedy, long a vaccine skeptic, fired all 17 members of ACIP, claiming that the group was rife with conflicts of interest and that a clean sweep was needed to restore public trust. Kennedy also reassigned CDC staff scientists who oversee the panel’s work and vet its members.

On the social platform X, he promised not to replace the panel’s experts with “ideological anti-vaxxers.” On Wednesday, Kennedy named eight new members, at least half of whom have expressed skepticism of certain vaccines. Only one was a widely recognized expert in vaccines.

For years, Kennedy has argued that American children receive too many shots and has falsely claimed that vaccines are not tested in placebo-controlled studies. Critics fear he is now setting the stage for a rollback of federal recommendations.

Worried about kids

“I’m very, very worried about young children in this country,” said Dr. Helen Chu, professor of medicine at the University of Washington and one of the committee members who was fired. If the panel’s new members “don’t believe in vaccines, then I think it puts us in a very dangerous place.”

Richard Hughes IV, who teaches vaccine law at George Washington University, predicted that the new committee would move to pare back the childhood vaccination schedule “relatively quickly.”

The Department of Health and Human Services did not respond to a request for comment.

“All of these individuals are committed to evidence-based medicine, gold-standard science, and common sense,” Kennedy said in a message on X. “They have each committed to demanding definitive safety and efficacy data before making any new vaccine recommendations.”

He also acknowledged that the panel would “review safety and efficacy data for the current schedule as well.”

The upheaval arrives as measles infections approach the highest level in decades; whooping cough has risen significantly, too, compared with this time last year. Steep cuts to global immunization programs also make it more likely that infectious diseases, such as polio, may reach American shores.

Alarmed, members of the House Committee on Oversight and Government Reform have asked Kennedy to provide all communications and documents related to the dismissal of the committee and a “detailed description of the rationale for removing each individual” by June 24, according to a letter obtained by The New York Times.

The American Medical Association called for an immediate reversal of the purge and resolved to “identify and evaluate” alternative sources of advice on vaccines. It is unclear whether Kennedy will appoint more members — there is no required minimum — before the next scheduled meeting at the end of June.

But any softening of federal recommendations regarding vaccination would ripple through the nation in unpredictable ways. Access to the shots eventually may depend on where you live, which insurance policy you hold and which doctor you see, experts said.

“That obviously is going to decrease the number of people who are protected with these vaccines,” said Dr. Mysheika Roberts, the health commissioner of Columbus, Ohio. “I am concerned about what that means about herd immunity, what that means about outbreaks and infections.”

Under the Affordable Care Act, insurance companies are required to cover the cost of any vaccine recommended by the ACIP. Losing that endorsement means that some insurance companies may choose not to pay for immunizations.