ATLANTA — Health Secretary Robert F. Kennedy Jr.’s new vaccine advisers alarmed pediatricians Wednesday by announcing inquiries into some long-settled questions about children’s shots.

Opening the first meeting of Kennedy’s handpicked seven-member panel, committee chairman Martin Kulldorff said he was appointing a work group to evaluate the “cumulative effect” of the children’s vaccine schedule — the list of immunizations given at different times throughout childhood.

Also to be evaluated, he said, is how two other shots are administered — one that guards against liver-destroying hepatitis B and another that combines chickenpox protection with MMR, the measles, mumps and rubella vaccine.

It was an early sign of how the Advisory Committee on Immunization Practices is being reshaped by Kennedy, a leading anti-vaccine activist before becoming the nation’s top health official. He fired the entire 17-member panel this month and replaced it with a group that includes several anti-vaccine voices.

“Vaccines are not all good or bad,” Kulldorff said. “We are learning more about vaccines over time” and must “keep up to date.”

His announcement reflected a common message of vaccine skeptics: that too many shots may overwhelm kids’ immune systems or that the ingredients may build up to cause harm. Scientists say those claims have been repeatedly investigated with no signs of concern.

Kids today are exposed to fewer antigens — immune-revving components — than their grandparents despite getting more doses, because of improved vaccine technology, said Dr. Paul Offit, a vaccine expert at Children’s Hospital of Philadelphia.

The American Academy of Pediatrics announced Wednesday that it will continue publishing its own vaccine schedule for children but now will do so independently of the ACIP, calling it “no longer a credible process.”

The panel, created more than 60 years ago, helps the CDC determine who should be vaccinated against a list of diseases, and when. Those recommendations have an impact on whether insurance covers vaccinations and where they’re available, such as at pharmacies.

After Kennedy’s dismissal of the 17-member panel earlier this month, a number of the CDC’s top vaccine scientists resigned or have been moved out of previous positions.

And shortly before Wednesday’s meeting, a Virginia-based obstetrician and gynecologist appointed to the committee stepped down. According to the Trump administration, he withdrew during a customary review of members’ financial holdings.

First on the committee’s agenda Wednesday were COVID-19 vaccinations. Kennedy already sidestepped the panel and announced the vaccine will no longer be recommended for healthy children or pregnant women.

Yet CDC scientists told the panel that vaccination is “the best protection” during pregnancy, and said most children hospitalized for COVID-19 over the past year were unvaccinated.

COVID-19 remains a public health threat, resulting in 32,000 to 51,000 U.S. deaths and more than 250,000 hospitalizations since last fall, according to the CDC. Most at risk for hospitalization are seniors and children younger than 2 — especially infants under 6 months who could have some protection if their mom was vaccinated during pregnancy, according to the CDC’s presentation.

The new advisers weren’t asked to vote on Kennedy’s recommendations, which raise uncertainty about how easily people will be able to access COVID-19 vaccinations this fall.

After CDC staff outlined multiple overlapping systems that continue to track the vaccines’ safety, several advisers questioned if the real-world data really is trustworthy.

On Thursday, the advisory panel is set to consider a preservative in a subset of flu shots that Kennedy and some anti-vaccine groups have falsely contended is tied to autism.