In a chaotic and deeply confusing meeting, federal advisors cast an 8-to-3 vote on Thursday to restrict the combined measles, mumps, rubella, and chickenpox (MMRV) vaccine for children under four years old.
The session concluded abruptly without a decision on whether newborns should receive the standard hepatitis B vaccine, a crucial immunization against a highly infectious, liver-damaging disease. This vote was deferred to Friday.
Roughly half of the panel members were recent appointments by Health Secretary Robert F. Kennedy Jr. The rushed formation of the committee was evident as many appointees required basic explanations of meeting procedures, scientific study design, and significant flaws in the data they proposed to consider. Dr. Martin Kulldorff, chair of the Advisory Committee on Immunization Practices, was observed during the meeting in Atlanta.
Several panelists also appeared unfamiliar with the Vaccines for Children program, which supplies free immunizations to nearly half of all American children. A primary role of this committee is to approve which vaccines fall under this vital program.
Despite the controversy, the decision to revoke the MMRV recommendation is not expected to have far-reaching effects, as guidelines for individually administered measles, mumps, rubella, and chickenpox vaccines—the more common approach—remain in place.
Adding to the day’s strangeness, members confusingly voted 8-to-1 to keep the MMRV vaccine covered by the Vaccines for Children program for kids under four, despite earlier restricting its use. Three members abstained, one specifically due to confusion.
Nonetheless, this vote likely marks the initial step in a series of planned revisions to official routine immunization recommendations.
During an extensive discussion, which included scientific presentations and fervent appeals from medical organizations, committee members seemed to favor limiting the hepatitis B vaccine. Their inclination was to provide it only to newborns whose mothers are confirmed infected, and to other infants only after they reach one month of age.
However, experts warned that such restrictions would elevate risks for newborns. Many pregnant women carrying hepatitis B are not identified, even with routine testing, due to missed screenings, inaccurate results, or issues in reporting and interpreting test outcomes.
Chari Cohen, President of the Hepatitis B Foundation, stated, ‘It will be challenging to identify all positive mothers and ensure a birth dose is available to those infants in hospitals, especially for those lacking prenatal care.’
She added, ‘Consequently, many babies born to infected mothers are likely to be missed, potentially leading to new chronic hepatitis B infections among these newborns.’
A distinct vote concerning COVID-19 vaccine recommendations is also slated for Friday.
According to Chairman Martin Kulldorff, the Advisory Committee on Immunization Practices (ACIP) also formed two new working groups: one to examine vaccine usage during pregnancy and another to re-evaluate existing childhood and adolescent vaccination schedules.
The prospect of the new administration altering the childhood vaccine schedule has deeply concerned numerous public health experts. They fear that limiting certain vaccines could lead to the reappearance of diseases long considered eradicated.
Dr. Sean T. O’Leary, chair of the infectious diseases committee for the American Academy of Pediatrics, warned, ‘If individuals cannot access vaccines, we will witness the return of diseases that once posed severe health threats to children.’
He concluded, ‘These diseases are now almost entirely preventable, and as a pediatrician, it is heartbreaking to see a child and family endure such suffering.’
The Childhood Vaccination Schedule Under Review
An included graphic, ‘The childhood vaccination schedule,’ provided context for the discussion. It outlined the suggested schedule of childhood vaccinations, from birth through 16 years. Three vaccines highlighted as being under review this week included the Hepatitis B shot (at birth, 1 month, and 6 months), the combined measles, mumps, and rubella and chickenpox shot (at 12 months and four years), and the Covid-19 shot (starting at 6 months).
Note: The start of the age range for each recommended dose is shown. Correction: An earlier version of this table incorrectly showed a second dose of the HPV vaccine at 16 years of age. The first dose is typically given around 11 years of age, and the second dose is recommended six to 12 months later. The graphic’s content was attributed to Elena Shao, Amy Schoenfeld Walker, and Daniel Wood.
Introduced in 2005, the MMRV vaccine offers an alternative to separate shots for measles, mumps, rubella (MMR), and varicella (chickenpox).
During Thursday’s meeting, Centers for Disease Control and Prevention scientists presented data indicating a slight increase in fever-induced seizure risk with the MMRV combination vaccine. While these seizures can accompany common childhood illnesses like ear infections and are not typically harmful, the finding contributed to the panel’s decision.
The CDC has historically advised separate administration of MMR and chickenpox vaccines for children under four, precisely due to the potential seizure risk.
Still, some pediatricians and parents chose the MMRV combination shot to reduce clinic visits and injections. The panel’s new recommendation aims to remove this option.
This decision met with strong objections from experts across various medical organizations. For instance, a visual depicts a hepatitis B shot being prepared for a 1-month-old patient, underscoring the practical implications of these policy changes.
Dr. Amy Middleman, head of pediatrics and adolescent medicine at Case Western Reserve University and a liaison to the committee, noted that Thursday’s MMRV discussion conspicuously lacked the typical presentations on feasibility, public acceptance, cost-benefit analysis, or equity considerations.
Dr. Middleman urged the committee to adhere to a methodical, evidence-based process for recommendations, especially given the broad public health implications of their decisions.
Earlier, Susan Monarez, who was removed as CDC director after less than a month, 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 shaped state vaccine mandates and mandated insurance coverage. However, its recent actions seem to have diminished its credibility and influence.
Following the committee’s initial meeting in June, several medical organizations ended their long-standing partnership with the panel, opting to issue their own independent recommendations.
On Tuesday, major insurers publicly stated their commitment to continue covering routine immunizations through 2026, irrespective of any panel decisions to restrict vaccine use. Senator Bill Cassidy, chairman of the Senate health committee, advised Americans on Wednesday not to trust the panel’s revisions to childhood vaccine recommendations.
The MMRV discussion underscored palpable tensions among the panelists.
Dr. H. Cody Meissner, a pediatrician from Dartmouth Geisel School of Medicine and a highly respected expert in vaccine science, remarked, ‘What we’re essentially saying is, we don’t trust parents to make these decisions.’
He warned that if the panel voted against the combination vaccine, it ‘won’t be an option’ for families.
The majority of current panelists are new appointments; in June, Mr. Kennedy dismissed all 17 previous committee members and installed seven new ones, many of whom share his vaccine-skeptical views. He added five more members just this week. Traditionally, ACIP members undergo months, even years, of vetting before being selected. Robert Malone, a member of the vaccine panel, abstained from votes on the M.M.R.V. vaccine.
At their June meeting, the initial seven panelists declared their intention to thoroughly review all recommended childhood and adolescent vaccinations. They also voted to withdraw a long-standing recommendation for a small category of flu shots containing thimerosal, a preservative that anti-vaccine groups have erroneously linked to autism.
Although the panel was expected to revise hepatitis B vaccine recommendations on Thursday, the decision was delayed until Friday due to a ‘small discrepancy’ in the vote’s wording, as stated by a Department of Health and Human Services spokesman. Neither he nor Dr. Kulldorff provided further details.
The initial dose of the hepatitis B vaccine is typically administered to newborns within 24 hours of birth. Public health experts credit this vaccine with nearly eradicating maternal transmission of the disease in the U.S., reducing annual incidence from approximately 20,000 cases before 1991 to fewer than 20.
Untreated hepatitis B can cause severe liver damage, including cirrhosis, liver failure, and cancer. Infants 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 supporters have asserted, controversially, that hepatitis B is transmitted exclusively through sexual contact or shared needles, suggesting that only infants born to infected mothers should receive the vaccine at birth.
Dr. Noele P. Nelson, a lead author of the current vaccine guidelines and a former head of the CDC’s hepatitis vaccines work group, pointed out that a pregnant woman’s hepatitis B status is not always reliably known.
She added that infections could also be missed due to inaccurate test results.
Dr. Nelson emphasized that ‘hepatitis B vaccination at birth for all newborns provides an effective safety net, ensuring that infants born to mothers with unknown or inaccurate infection status are protected.’ She resigned from the CDC in July.
Dr. James Campbell, vice chair of the American Academy of Pediatrics’ infectious disease committee, clarified that hepatitis B is a highly contagious virus that can spread beyond sexual contact, including through shared household items like toothbrushes, razors, or combs.
He explained, ‘In the past, we had risk-based hepatitis B vaccination recommendations, but they failed to reduce the overall disease burden. That’s why universal recommendation is now the standard.’
Mr. Kennedy has repeatedly questioned the safety and testing protocols of the hepatitis B vaccine, making unsubstantiated claims. During his January confirmation hearing, he notably declined to affirm that the hepatitis B vaccine does not cause autism, despite widespread scientific consensus to the contrary.
Conversely, Dr. Claudia A. Hawkins, a specialist in hepatitis B and C at Northwestern University’s Feinberg School of Medicine, affirmed that hepatitis B vaccines are ‘very safe, with no serious side effects reported in infants, children, or adults since their inception.’
She concluded, ‘There is no justifiable reason to delay the hepatitis B vaccine.’
Correction: An earlier version of this article incorrectly stated the date that AHIP, the national trade association for health insurance, confirmed health plans would continue covering all immunizations recommended as of September 1st. The correct date was Tuesday, September 16th, not Wednesday.
Apoorva Mandavilli is a science and global health reporter for The Times, specializing in infectious diseases, pandemics, and the public health bodies tasked with managing them.
This article appeared in the New York print edition on September 19, 2025, in Section A, Page 16, under the headline ‘Kennedy’s Vaccine Panel Restricts M.M.R.V. Shot.’