New ACIP Panel Backs Seasonal Flu, RSV Vaccinations, but Divisions Emerge Over Thimerosal and Infant Dosing

ACIP decides on vaccinations

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Our sister brand, Medical Economics, first published this article.

The new members of the Advisory Committee on Immunization Practices (ACIP) have made recommendations on influenza and respiratory syncytial virus (RSV) vaccinations for the 2025-2026 flu season.

The votes came on the second day of ACIP’s first gathering, with its new members appointed by Health and Human Services (HHS) Secretary Robert F. Kennedy Jr. In public comment sessions on both days, physicians, activists, and public health advocates primarily spoke in favor of the widespread health benefits of vaccines, although some warned of adverse effects from treatments intended to prevent disease, rather than exacerbate patient health.

Staff presentations had information about influenza and RSV, both of which can pose severe health risks in individuals. There was also discussion about the safety of the vaccine preservative thimerosal, a mercury-containing organic compound used in drugs since the 1930s.

The members are Chair Martin Kulldorff, MD, PhD; Joseph R. Hibbeln, MD; Retsef Levi, PhD; Robert W. Malone, MD; Cody Meissner, MD; James Pagano, MD; and Vicky Pebsworth, OP, PhD, RN.

Influenza votes

The ACIP votes for influenza (flu) were:

• Influenza Vaccination Vote: Recommendations for Influenza Vaccination for the 2025-26 Season: The ACIP reaffirms the recommendation for routine annual influenza vaccination of all persons aged 6 months or older who do not have contraindications. Approved 6-0, 1 abstention.
• Thimerosal Containing Influenza Vaccines Vote No. 1: ACIP recommends that children 18 years and younger receive seasonal influenza vaccines only in single-dose formulations that are free of thimerosal as a preservative. Approved 5-1, 1 abstention.
• Thimerosal Containing Influenza Vaccines Vote No. 2: ACIP recommends pregnant women receive seasonal influenza vaccines only in single-dose formulations that are free of thimerosal as a preservative. Approved 5-1, 1 abstention.
• Thimerosal Containing Influenza Vaccines Vote No. 3: ACIP recommends all adults receive seasonal influenza vaccines only in single-dose formulations that are free of thimerosal as a preservative. Approved 5-1, 1 abstention.

Voting rationales

Afterward, the members explained their votes.

“I think we need to work hard to bring to the public the most accurate scientific assessments of the efficacy of these vaccines,” Levi said.

“I wish to note that there is a significant benefit to the use of multidose vaccines instead of single-dose vaccines, and apparently, there is good data that other preservatives can be used,” Hibbeln said. “So, I hope that the committee will put on the agenda the consideration of multiuse vials rather than single-use vials that have other better preservatives.”

“I wish to note regarding the recommendations for influenza vaccine for the season and the recommendation for routine annual influenza vaccination for all persons greater than or equal to 6 months lacking contraindications, I look forward to a robust evaluation in the subcommittee of the potential risks and benefits, relatively speaking of the alternative products that are currently available on the market. And I anticipate, there will be active consideration of the long-standing issue of immune imprinting and original antigenic sin, which may or may not be a concern in the case of routine annual influenza vaccination,” Malone said.

“I would like to make the point that my concern is that by insisting the multi-dose vials contain thimerosal, that might limit the availability of the influenza vaccine for some people,” Meissner said. “I would like to have that question answered, but it's probably a difficult one to answer. My point is, the risk from influenza is so much greater than the non-existent, as far as we know, risk from thimerosal, so I would hate for a person not to receive the influenza vaccine because the only available preparation contains thimerosal. I find that very hard to justify.”

“I wanted to say that I, on my personal views on this, is that we should not be doing anything that restricts access to vaccines of any sort, especially those that are already approved by the FDA and that are already in the schedule,” Pebsworth said. “My problem and the reason I abstained for all of these votes is because the way the voting question was written. In the world of survey research, you don't ask two things in the same question. So, there's buried in this, is a recommendation that all adults receive seasonal influenza, and then the second part of it, in formulations that are free of thimerosal as a preservative. Yes, I think we should not be using thimerosal as a preservative. But we didn't get into any sort of a discussion about the first part of the question. In the future, when we're asked to vote on something, if we could just vote on one thing at a time, that would be helpful.”

RSV votes

ACIP also voted on the RSV vaccine.

• Vote: ACIP recommends that infants aged less than 8 months born during or entering their first RSV season who are not protected by maternal vaccination receive 1 dose of clesrevumab. Approved 5-2.

Levi and Pebsworth voted no.

“I just want to clarify that my objection is based on the fact that I don't feel this is ready to be administered to all healthy babies. I think we should take them on precautionary approach to this, but I respect the discussion in my opinions of my colleagues.

Pebsworth did not state a reason for her vote.

• Vote: Approve the updated Vaccines for Children (VFC) resolution for prevention of RSV. Approved 7-0

Malone asked about the language the committee would vote on, and there was some discussion to clarify it. The members also offered brief explanations about that vote.

“This is extremely important that VFC cover this product,” Meissner said. “It is very important to ensure equity in our country so that all children have access to these monoclonal antibodies. It would not be right because these are expensive products, that only well-insured children or in families that are well-insured, have access to this product. I think we've all discussed the fact that this is an effective product, and I would strongly encourage everyone to make it available to all children.”

Malone did not disagree, but explained he wanted to clarify his understanding of the language and procedure. During the vote, Levi agreed on the importance of making the vaccine accessible to any children, and he suggested a further CDC study of post-marketing data on any deaths and adverse events.

Pebsworth recited her statement regarding a potential conflict of interest, owning shares in a health care sector fund that has holdings relevant to ACIP, including those of vaccine manufacturers. The amount is less than the Office of Government Ethics’ regulatory de minimis amount.

After the vote, Kulldorff thanked the ACIP members and their advising staff for immersing themselves in a study about a vaccine that the Food and Drug Administration had approved just 16 days prior.