Health Secretary Robert F. Kennedy Jr. is clearly moving to overhaul the standard childhood vaccination schedule. A federal advisory committee, meeting on Thursday, is expected to recommend against a specific combination vaccine for children under four that protects against measles, mumps, rubella, and chickenpox.
This particular decision by the committee, whose members were all chosen by Mr. Kennedy, isn’t anticipated to have widespread immediate effects, as separate vaccines for these diseases (the more common approach) will still be recommended.
However, this vote is likely just the beginning of many changes to the official guidance on routine childhood immunizations.
According to Martin Kulldorff, the panel’s chair, the Advisory Committee on Immunization Practices (ACIP) plans to form two new working groups: one to examine vaccine use during pregnancy and another to scrutinize existing childhood and adolescent vaccination schedules.
Many public health experts are deeply troubled by these plans, fearing that restricting access to certain vaccines could lead to the re-emergence of diseases that were once largely eradicated.
The committee is also expected to vote on Thursday to limit the use of the hepatitis B vaccine. This highly infectious disease can severely damage the liver. The proposed new recommendation would only administer this vaccine to newborns whose mothers are confirmed to be infected, or to other babies at least one month old.
“If children cannot easily get vaccines, we risk seeing the return of serious childhood illnesses,” warned Dr. Sean O’Leary, chair of the infectious disease committee for the American Academy of Pediatrics. He added, “These diseases are almost entirely preventable now, and it’s heartbreaking as a pediatrician to witness a child and family suffer from them.”
The MMRV vaccine, available since 2005, offers an alternative to giving two separate injections: one for measles, mumps, and rubella (MMR) and another for varicella (chickenpox).
Panel members indicated their intention to closely examine the MMRV shot during their initial meeting in June.
During Thursday’s session, scientists from the Centers for Disease Control and Prevention (CDC) presented data suggesting the combination vaccine slightly increases the risk of seizures associated with fever. While these febrile seizures can also occur with common childhood ailments like ear infections and don’t typically cause long-term harm, they are a factor.
The CDC previously advised giving the MMR and chickenpox shots separately to children under four precisely because of this slight seizure risk.
Despite this, some pediatricians and parents chose the MMRV combination shot to reduce the number of doctor’s visits and injections. The panel’s upcoming vote aims to remove this option entirely.
Medical organizations outside the committee voiced strong opposition to the proposal to recommend against the vaccine.
Dr. Amy Middleman, head of pediatrics and adolescent medicine at Case Western Reserve University and a liaison to the committee, noted that the MMRV discussion lacked standard presentations on feasibility, acceptability, cost-benefit analysis, or equity concerns.
A recommendation against the MMRV vaccine would mean that it would no longer be covered by critical programs like Vaccines for Children, which supplies immunizations to roughly half of American children, or the Children’s Health Insurance Program, serving low-income families.
“I urge the committee to follow a thorough, evidence-based process before making a decision that has such a significant impact on public health,” Dr. Middleman emphasized.
Susan Monarez, who was ousted from the C.D.C. after less than a month as its director, informed lawmakers on Wednesday that Mr. Kennedy intended to revise the childhood immunization schedule.
She testified that Mr. Kennedy instructed her to approve every panel recommendation “regardless of the scientific evidence.”
Historically, ACIP’s decisions have guided state vaccine mandates, and insurers are typically required to cover recommended shots. However, the panel’s recent actions appear to have undermined its authority.
Following the committee’s first meeting in June, several medical organizations ended their decades-long collaboration with ACIP, choosing instead to issue their own vaccination recommendations.
On Tuesday, most major insurers said they would continue to cover routine immunizations through 2026, even if ACIP voted to restrict their use. Senator Bill Cassidy, Republican of Louisiana and chair of the Senate health committee, also stated on Wednesday that Americans should not trust the panel’s efforts to revise childhood vaccine recommendations.
The MMRV discussion highlighted evident tensions among the committee members.
“What we’re saying is we don’t trust parents to make a decision,” said Dr. Cody Meissner, a pediatrician at Dartmouth Geisel School of Medicine, who is widely respected for his expertise in vaccine science. He pointed out that if the panel rejects the combination vaccine, parents “won’t have that option” at all.
Most of the current panelists are new appointments. In June, Mr. Kennedy dismissed the 17 previous members of the committee, and brought in seven new ones, many of whom share his skeptical views on vaccines. He later announced five additional members earlier this week. ACIP members traditionally undergo extensive vetting over many months or even years before being invited to join.
At their June meeting, the seven initial panelists declared their intention to review all recommended vaccinations for children and adolescents. They also voted to reverse a long-standing recommendation for a small category of flu shots containing thimerosal, a preservative that anti-vaccine groups have falsely linked to autism.
Hepatitis B vaccine recommendations are also slated for revision on Thursday. This vaccine, typically given to newborns within 24 hours of birth, has been instrumental in almost eliminating maternal transmission of the disease in the U.S. Incidences have dropped from approximately 20,000 cases annually before 1991 to fewer than 20 cases a year.
Untreated hepatitis B can cause severe liver damage, including cirrhosis, liver failure, and cancer. Babies infected at birth face a 90% chance of developing chronic hepatitis B, with one in four experiencing severe complications or death from the illness.
Mr. Kennedy and his allies contend that hepatitis B is exclusively transmitted through sexual contact or shared needles, suggesting that only infants born to infected mothers require immunization at birth.
Dr. Noele Nelson, a lead author of the vaccine’s current guidelines and former head of the CDC’s hepatitis vaccines work group, highlighted that a pregnant woman’s hepatitis B status is not always known, or could be inaccurately reported or interpreted.
She asserted, “Universal hepatitis B vaccination for all newborns acts as a crucial safety net, ensuring protection for infants whose mothers have unknown or misidentified infection statuses.” Dr. Nelson resigned from the CDC in July.
Hepatitis B, a highly contagious virus, can spread through non-sexual means, including shared household items like toothbrushes or razors, said Dr. James Campbell, vice chair of the infectious disease committee for the American Academy of Pediatrics.
“Past risk-based recommendations for hepatitis B vaccination did not effectively reduce the overall disease burden,” he explained, reinforcing the need for the current universal recommendation.
Mr. Kennedy has repeatedly questioned the safety of the hepatitis B vaccine, incorrectly claiming it was not properly tested. During his January confirmation hearing, he notably refused to acknowledge the scientific consensus that the hepatitis B vaccine does not cause autism.
Conversely, Dr. Claudia Hawkins, a specialist in hepatitis B and C at Northwestern University Feinberg School of Medicine, stated unequivocally that hepatitis B vaccines are “very safe, with no reported serious side effects in babies, children, or adults since their introduction.” She concluded, “There is no medical reason to delay the hepatitis B vaccine.”
A separate vote concerning Covid vaccines is scheduled for Friday.
A correction published on September 18, 2025: This article previously misstated that AHIP, a national health insurance trade association, announced on Tuesday, September 16, that health plans would continue to cover all recommended immunizations. It was not Wednesday, September 17.