In a meeting marred by confusion and near chaos, federal advisors on Thursday voted 8 to 3 against administering a combination vaccine for measles, mumps, rubella, and chickenpox (MMRV) to children under four years old. The panel postponed a planned vote on whether newborns should receive the standard hepatitis B vaccine, which combats a highly infectious liver disease, until Friday. Roughy half of the committee members were recent appointees by Health Secretary Robert F. Kennedy Jr. Their lack of familiarity with standard meeting protocols, scientific study design, and data evaluation highlighted the hasty assembly of the committee. Many panelists also appeared unfamiliar with the purpose of the Vaccines for Children program, a critical federal initiative that provides free vaccinations to about half of all American children. Approving which vaccines this program covers is a primary responsibility of the committee.
Dr. Martin Kulldorff, chair of the Advisory Committee on Immunization Practices, is seen speaking during the meeting in Atlanta on Thursday. (Credit: Alyssa Pointer/Reuters)
This decision to revoke the MMRV recommendation is unlikely to cause widespread impact, as guidelines for individually administered measles, mumps, rubella, and chickenpox vaccines—the more common practice—remain unchanged. In an unusual turn, members paradoxically voted 8 to 1 for the Vaccines for Children program to continue covering the MMRV vaccine for children under four, despite having just voted against its recommendation. Three members abstained, one explicitly citing his confusion. Nevertheless, this vote signals potentially numerous alterations to official routine immunization recommendations. During several hours of discussion, committee members seemed inclined to limit the hepatitis B vaccine to newborns whose mothers are confirmed to be infected, and for other infants, only after they reach one month of age. However, experts warn that such a change would significantly increase risks for newborns. Many hepatitis B infections in pregnant women are not detected, even with routine testing, due to inaccurate results or issues with reporting and interpretation. Chari Cohen, president of the Hepatitis B Foundation, stated, “It will be challenging to identify all positive moms, and ensure that a birth dose is available to those infants in hospitals, especially for those who do not receive prenatal care. So it is likely that many babies born to positive moms will be missed. We will likely see new chronic hepatitis B infections among some new babies.” A separate vote regarding Covid-19 vaccine recommendations is also slated for Friday. The Advisory Committee on Immunization Practices (ACIP) also formed two new work groups, announced Chairman Martin Kulldorff: one dedicated to analyzing vaccine use during pregnancy, and another to reviewing childhood and adolescent vaccination schedules. Public health experts are deeply concerned that the new administration’s potential drastic changes to the childhood vaccine schedule could lead to the resurgence of diseases that were once largely eradicated. Dr. Sean T. O’Leary, chair of the infectious diseases committee for the American Academy of Pediatrics, emphasized, “If people cannot access vaccines, we will see the return of diseases that once caused serious health issues for children. These diseases are now almost entirely preventable, and as a pediatrician it is heartbreaking to see a child and family suffer in this way.”
An interactive graphic titled ‘The childhood vaccination schedule’ provides an overview of recommended vaccinations from birth through 16 years. It highlights three vaccines currently under review by the C.D.C.’s immunization advisory panel: Hepatitis B (at birth, 1 month, 6 months), the combined Measles, Mumps, Rubella, Varicella (MMRV) shot (at 12 months and 4 years), and the Covid-19 shot (starting at 6 months, available for high-risk children or after consultation with a doctor). The graphic notes that the MMRV combination shot is less commonly used than individual MMR and chickenpox doses. (Credit: By Elena Shao, Amy Schoenfeld Walker and Daniel Wood)
The MMRV vaccine, introduced in 2005, offers an alternative to separate shots for measles, mumps, rubella, and varicella (chickenpox). During Thursday’s meeting, CDC scientists presented data indicating a slight increase in fever-induced seizures associated with the combination vaccine. While such seizures can occur with common childhood illnesses, like ear infections, they typically cause no lasting harm. The C.D.C. has historically advised administering separate MMR and chickenpox shots for children under four due to this seizure risk. Despite this, some pediatricians and parents chose the MMRV shot to minimize clinic visits and injections. The panel’s recent decision aimed to remove this option. Other medical organizations have strongly opposed the panel’s actions.
A hepatitis B shot being prepared for a 1-month-old patient. (Credit: Kristian Thacker for The New York Times)
Dr. Amy Middleman, head of pediatrics and adolescent medicine at Case Western Reserve University and a committee liaison, expressed concern that Thursday’s MMRV discussion lacked critical components like feasibility, acceptability, cost-benefit analysis, and equity considerations. “I would urge the committee to follow the methodical process of an evidence-to-recommendation process before voting on something that affects the public health to this degree,” she stated. Earlier, Susan Monarez, who briefly served as CDC director, informed lawmakers that Mr. Kennedy had instructed her to approve all panel recommendations “regardless of the scientific evidence.”
Historically, the advisory panel’s decisions have guided state vaccine mandates, and insurers are required to cover recommended shots. However, recent actions by the panel appear to have diminished its credibility. Following the committee’s initial meeting in June, several medical organizations broke their longstanding partnership with the panel, opting to issue their own recommendations. Furthermore, on Tuesday, most major insurers confirmed they would continue to cover routine immunizations through 2026, irrespective of any restrictive votes by the panel. Senator Bill Cassidy, Republican of Louisiana and chairman of the Senate health committee, also cautioned Americans against trusting the panel’s revised childhood vaccine recommendations. Tensions among the panelists were evident during the MMRV discussion. Dr. H. Cody Meissner, a pediatrician from Dartmouth Geisel School of Medicine and a highly respected expert on vaccine science on the panel, remarked, “What we’re saying is, We don’t trust parents to make a decision,” adding that if the panel voted against the combination vaccine, it would no longer be an option. Most current panelists are new members. In June, Mr. Kennedy dismissed all 17 previous committee members and appointed seven new ones, largely aligned with his skeptical views on vaccines. He added five more members this week. Typically, ACIP members undergo months or even years of vetting before appointment.
When the Advisory Committee on Immunization Practices, with seven new panelists, met in June, they announced that they would scrutinize all the vaccinations recommended for children and adolescents. (Credit: Elijah Nouvelage/Getty Images)
During their June meeting, the initial seven panelists declared their intention to meticulously examine all recommended vaccinations for children and adolescents. They also rescinded a long-standing recommendation for a small subset of flu shots containing thimerosal, a preservative falsely linked to autism by many anti-vaccine groups. The panel was expected to revise hepatitis B recommendations on Thursday but postponed the decision to Friday due to a “small discrepancy” in the vote’s wording, according to a Department of Health and Human Services spokesman, who, along with Dr. Kulldorff, declined to elaborate. The first hepatitis B vaccine dose is typically given to newborns within 24 hours of birth. This vaccination is credited by public health experts for nearly eradicating maternal transmission of the disease in the U.S., reducing yearly cases from approximately 20,000 before 1991 to fewer than 20. Untreated hepatitis B can lead to 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. Mr. Kennedy and his allies have incorrectly asserted that hepatitis B is exclusively transmitted through sexual contact or shared needles, suggesting that only infants of infected mothers should be immunized at birth. Dr. Noele P. Nelson, a lead author of the current vaccine guidelines and former head of the C.D.C.’s hepatitis vaccines work group, noted that a pregnant woman’s hepatitis B status is not always known, and tests can yield inaccurate results. “Hepatitis B vaccination at birth for all newborns provides an effective safety net,” she explained, “ensuring that infants born to mothers with unknown or inaccurate infection status are protected.” Dr. Nelson resigned from the C.D.C. in July. Dr. James Campbell, vice chair of the American Academy of Pediatrics’ infectious disease committee, added that hepatitis B can spread through non-sexual means, including shared household items like toothbrushes or razors. “We’ve had, in the past, risk-based hepatitis B vaccination recommendations, and they did not reduce the overall burden,” he said. “That’s why we have universal recommendation now.” Mr. Kennedy has questioned the safety and testing protocols of the hepatitis B vaccine, and during his confirmation hearing in January, he avoided confirming that the vaccine does not cause autism, a scientific consensus. However, Dr. Claudia A. Hawkins, who treats hepatitis B and C patients at Northwestern University’s Feinberg School of Medicine, affirmed that hepatitis B vaccines are “very safe, with no reports of any serious side effects in babies, children or adults since their introduction.” She concluded, “There is no reason to delay the hepatitis B vaccine.”
**Correction (Sept. 18, 2025):** An earlier version of this article incorrectly stated that AHIP, the national trade association for health insurance, made its statement on vaccine coverage on Wednesday. It was made on Tuesday, Sept. 16.