Addressing Concerns and Missteps From the Latest ACIP Meeting

The June 25–26 meeting of the CDC’s Advisory Committee on Immunization Practices (ACIP) should’ve continued the long-standing tradition of evidence-based, expert-driven vaccine recommendations. Instead, it left many in the infectious disease and public health communities deeply concerned.

This was the first ACIP meeting since the U.S. Department of Health and Human Services (HHS) dismissed all 17 sitting volunteer members – scientists and physicians with extensive, vetted expertise – and installed eight handpicked replacements days later. 

Calls from bipartisan lawmakers, professional medical associations, and 40 former ACIP members and public health leaders to postpone the meeting until the committee’s balance and independence could be restored were ignored.

The Partnership to Fight Infectious Disease joins these voices in urging HHS and CDC to:

• Reaffirm the critical role of independent scientific expertise in health policymaking.

• Restore ACIP’s transparent, evidence-based structure and public credibility.

• Ensure all future changes to committee membership follow established, transparent,  accountable processes.

ACIP's role in American health is too vital to jeopardize. The committee’s vaccine recommendations shape immunization schedules, influence public confidence, and determine insurance and federal coverage. When proceedings are misleading or haphazard, the consequences ripple far beyond the committee room.

Click here to learn more about ACIP and see below for three topics in the June meeting that highlight these concerns.

Reviving Long-Resolved Thimerosal Concerns

The committee’s discussion of thimerosal, a mercury-containing compound used in a small fraction of multi-dose flu vaccines, was dominated by a presentation that relied heavily on outdated studies, selectively cited data, and speculative claims. Notably, it bypassed the typical ACIP workgroup process and was not fact-checked in advance, violating long-standing protocol. 

This matters because thimerosal has been studied extensively, with credible results showing it is not linked to serious adverse events or conditions like autism. While 96% of flu vaccines are already thimerosal-free, the decision to eliminate the few remaining multi-dose vials that contain it – without scientific justification – will reinforce distrust and impact vaccine access in rural and low-income areas.

New Work Groups Based on Debunked Premises

ACIP’s decision to create a new working group to re-examine the childhood vaccination schedule lacks support from current scientific evidence and longstanding expert consensus. Today’s immunization schedules expose children to fewer antigens than in previous decades while protecting against more diseases.

In the early 1980s, the routine U.S. childhood immunization schedule included vaccines for seven diseases: diphtheria, tetanus, pertussis, polio, measles, mumps, and rubella. Today, children in the U.S. are routinely vaccinated against 14 diseases by age 6, including those above plus hepatitis B, Haemophilus influenzae type b (Hib), varicella (chickenpox), pneumococcal disease, rotavirus, hepatitis A, and influenza. The use of modern vaccine technologies and combination vaccines have reduced the number of antigens given by 15-fold.

According to the CDC, routine childhood immunizations for those born from 1994-2023 have prevented more than 500 million illnesses, 32 million hospitalizations, and 1.1 million deaths, saving an estimated $2.7 trillion in societal costs.

Reopening debate on a well-studied and highly effective childhood immunization schedule risks fueling public doubt and misinformation, especially at a time when vaccine confidence remains fragile.

Unprecedented Procedural Shortcuts Undermining Trust

ACIP’s process is supposed to be rigorous and transparent. Typically, recommendations are informed by working group reviews, evidence-to-recommendation frameworks, and assessments that evaluate the certainty of available data.

But at this meeting, the thimerosal presentation skipped all pre-meeting review steps, and a confusing vote on RSV monoclonal antibodies further underscored the lack of understanding among some new committee members. For example, some members voted against recommending a new RSV monoclonal antibody product, then voted in favor of covering it through the Vaccines for Children (VFC) program, a contradiction that reflects confusion or lack of procedural familiarity.

Dr. Sean O’Leary, the American Academy of Pediatrics’ liaison to ACIP, told reporters in a conference call he believes questions from certain committee members “were designed to sow mistrust in the data.”

“What I saw a number of times was CDC presenting the data and then questions being asked as if they hadn’t even paid attention to the data that were just presented,” O’Leary said, “as if they clearly had an agenda.”

These breakdowns have real-world consequences and convey that vaccine recommendations may be driven more by ideology than by sound science.