A panel of specialists responsible for guiding the Centers for Disease Control and Prevention (CDC) on vaccination strategies — rumored to come under scrutiny from Health and Human Services Secretary Robert F. Kennedy Jr. — has canceled its upcoming February session, as confirmed by a senior official from HHS on Thursday.

The Advisory Committee on Immunization Practices (ACIP) was slated to convene from February 26 to 28, marking its first meeting since the Trump administration assumed office. However, Andrew Nixon, the HHS communications director, informed STAT via email that this meeting will not take place. An official notice regarding the postponement was later published on the ACIP’s official website.

Nixon did not provide a specific date for the rescheduled meeting, stating only that it would occur “soon.”

Kennedy, who started his tenure at HHS on Tuesday, has publicly criticized the ACIP previously. During his Senate confirmation hearing, he claimed that 97% of ACIP members had conflicts of interest—an assertion that experts familiar with the stringent vetting processes of ACIP members have countered.

For several weeks, CDC staff responsible for organizing the committee’s activities sought final permission from HHS to proceed with the meeting, but their requests went unanswered. Prior to last week, the subcommittees and workgroups preparing for full committee discussions were prohibited from meeting due to a communication freeze imposed by the administration shortly after President Trump took office. According to multiple sources, these subcommittee meetings resumed last week.

Initially, the CDC was optimistic that the ACIP could hold its meeting in person at the agency’s headquarters. However, plans were eventually altered to conduct the meeting online as the secretariat awaited final approval.

The forthcoming meeting — the agenda for which has been accessible since early January — was intended to address various vaccination topics and vote on recommendations for a newly approved vaccine against chikungunya, a disease spread by mosquitoes; in addition to a new meningitis vaccine from GSK to be named Penmenvy, along with updated guidelines for influenza and RSV vaccines.

Any advisory committee meetings involving voting require a designated timeframe for public input. Individuals can submit comments in writing or enter a lottery for an opportunity to voice their opinions during the meeting. However, due to HHS’s refusal to formally authorize the meeting, the platform for public comment was not activated. Sources indicated this was the decisive factor leading the CDC’s ACIP secretariat to request the meeting’s postponement.

Nixon stated in his brief communication that the postponement was necessary to facilitate public comments before the meeting occurs.

Public health advocates are increasingly worried about the future of this committee, which has played a crucial role in assisting the CDC in determining the optimal application of approved vaccines. Vaccines recommended by the ACIP must be covered by health insurance, pending the CDC director’s endorsement of the recommendations. Historically, CDC directors have seldom rejected the ACIP’s advice.

Nearly twenty medical associations and advocacy organizations, including the American Medical Association and the Gerontological Society of America, along with numerous individual healthcare professionals, sent an open letter to Kennedy and acting CDC Director Susan Monarez, urging a swift rescheduling of the meeting. This initiative is led by the Partnership to Fight Infectious Disease.

Dorit Reiss, a law professor at UC Law San Francisco and an observer of the ACIP’s activities, described the postponement as “problematic in several respects,” highlighting the importance of several key votes that were planned. Reiss expressed concern that this action raises doubts about Mr. Kennedy’s commitment to Senator [Bill] Cassidy, who was assured that he would not obstruct ACIP recommendations.

Cassidy, a vaccine supporter, was noticeably cautious in backing Kennedy due to his controversial views on vaccine safety, which Kennedy did not retract during his Senate confirmation hearings. Cassidy eventually agreed to support Kennedy after obtaining specific assurances, including a pledge to “work within existing vaccine approval and safety monitoring frameworks and uphold the CDC’s vaccine advisory committee recommendations.”

Other experts worry that this delay may signal a potential dismantling of the committee, at least in its current configuration. Paul Offit, an infectious diseases specialist at Children’s Hospital of Philadelphia, noted that Project 2025, a set of policy suggestions led by the conservative Heritage Foundation, suggests that CDC officials should no longer be empowered to advise on vaccination mandates for school enrollment; such decisions should rest with parents and healthcare providers.

“This appears to be step one in efforts to eliminate CDC as a body making [vaccine] recommendations,” he remarked in an interview.

The ACIP serves multiple functions, from advising on the safe co-administration of vaccines to investigating signals of risk, ensuring that recommendations reflect new data. Increased concern around the potential for developing Guillain-Barré syndrome, a temporary paralysis condition, after receiving two RSV vaccines for older individuals led the committee to recommend more cautious use of these products than manufacturers preferred.

Fears regarding the committee’s future intensified when Trump signed an executive order on Wednesday, titled “Beginning the Reduction of the Federal Bureaucracy.” One provision within the order tasks aides with reviewing existing federal advisory committees — including ACIP — and reporting back within 30 days on which can be deemed unnecessary.

A CDC insider informed STAT that the agency was asked on Wednesday to provide written justification for the continued existence of several federal advisory committees functioning under its purview. There are approximately 20 federal advisory committees providing guidance to the CDC on a range of issues, from breast cancer rates in young women to injury prevention and mine safety. Committee members, who are not compensated employees, receive reimbursement for travel and may, specifically for ACIP members, receive a $250 honorarium for attending meetings designated as “special government employees.” Members are not compensated for the time dedicated to workgroups, which largely conduct the committee’s work.