New CDC vaccine advisers endorse thimerosal-free flu vaccines, despite no evidence of harm from the preservative

By Brenda Goodman, Meg Tirrell, CNN

(CNN) — A new slate of vaccine advisers to the US Centers for Disease Control and Prevention voted Thursday to recommend that Americans receive influenza vaccines that are free of thimerosal even though there is no evidence of harm from the preservative.

The closely watched vote was among the first for the newly assembled group, which was appointed by US Health and Human Services Secretary Robert F. Kennedy Jr. this month after he dismissed the previous panel of 17 experts, claiming that they had conflicts of interest.

However, some of the new members of the committee raised serious concerns from the public health community for their approach to vaccines and scientific evidence. The last-minute addition of thimerosal to the Advisory Committee on Immunization Practices’ meeting agenda was a signal to vaccine experts that Kennedy – who led an anti-vaccine group called Children’s Health Defense – was seeking to sow doubt about vaccine safety.

Thimerosal was largely removed from most vaccines about 25 years ago. The US Food and Drug Administration asked manufacturers to remove it out of an abundance of caution, not because of evidence of harm, according to the CDC. All vaccines routinely recommended for young children now are available in doses that don’t have the preservative, which contains a form of mercury.

Flu vaccines drawn from multidose vials still contain thimerosal in order to prevent bacterial contamination. Only about 4% of flu vaccines given in the United States last year contained thimerosal as a preservative.

Still, on Thursday, the committee heard an unusual presentation by Lyn Redwood, a nurse practitioner and former leader of Children’s Health Defense, which has advocated against the use of mercury in vaccines.

Unlike most other presentations given at the meeting, Redwood’s was not vetted or read by a working group or outside experts in vaccine science before it was voted on, according to Dr. Sean O’Leary, a pediatrician at Children’s Hospital of Colorado who has been a liaison member of the Advisory Committee on Immunization Practices, or ACIP.

“This selective use of data and omission of established science undermines public trust and fuels misinformation,” O’Leary said in a statement made on behalf of the American Academy of Pediatrics, which recently announced that it would no longer participate in ACIP meetings because of the changes to committee membership and what’s being discussed.

In a series of three votes Thursday, the ACIP members voted 5-1, with one member abstaining, to recommend that only single-dose flu vaccines be given to children, adults and pregnant women in the United States. Single-dose shots are free of thimerosal.

Drs. Robert Malone, Joseph Hibbeln, Martin Kulldorff, Retsef Levi and Joseph Pagano voted yes on the thimerosal recommendations. Dr. Cody Meissner voted no. Dr. Vicky Pebsworth, volunteer director of research and patient safety at the National Vaccine Information Center, a group that emphasizes risks around vaccines while downplaying their benefit, abstained from the vote because she objected to its wording.

In justifying his vote, Meissner, a professor of pediatrics at the Dartmouth Geisel School of Medicine, said he was worried that expressing a preference for single-dose vials might keep people from getting doses from multidose formulations in situations in which those shots may be the only option.

“That might limit the availability of the influenza vaccine for some people,” he said.

“My point is, the risk from influenza is so much greater than the nonexistent — as far as we know — risk from thimerosal, so I would hate for a person not to receive the influenza vaccine,” Meissner said. “I find that very hard to justify.”

Six members of the committee voted to continue to recommend that everyone 6 months and older receive an annual flu vaccine. Pebsworth abstained.

Vaccines with thimerosal are still approved by the FDA. The ACIP recommendation now goes to the CDC director or potentially to Kennedy, as CDC nominee Dr. Susan Monarez is still awaiting Senate confirmation.

However, ACIP recommendations are tremendously influential in how vaccines are used in the US, with implications for insurance coverage and state policies.

Advisers endorse Merck RSV antibody

The advisers also voted 5-2 on Thursday to recommend the use of a new shot that can protect babies from respiratory syncytial virus, adding an additional tool against the most common cause of hospitalization in infants.

The shot, called clesrovimab and given the brand name Enflonsia, is made by Merck and joins two other interventions already on the market to protect babies against severe disease from RSV, a common virus that can be especially dangerous for infants. One, like clesrovimab, is an antibody shot, and the other is a vaccine given during pregnancy.

Data presented at the meeting showed that the approved interventions were safe and dramatically reduced hospitalizations among babies from RSV in the last respiratory virus season.

“As a pediatrician, I mean, people need to understand what a spectacular accomplishment these results are,” Meissner said at Wednesday’s ACIP meeting. They “will have an enormous influence on public health.”

The new drug was approved this month by the FDA, and the CDC committee’s recommendation was the next step in making it widely available for the coming RSV season, which typically begins in the fall.

The vote came after Levi, a professor of operations management at the Massachusetts Institute of Technology Sloan School of Management, raised questions Thursday morning about whether there were safety signals that arose in clinical trials of the antibody shots that deserve further scrutiny. Representatives from both the FDA and Merck emphasized the safety of the product and the rigor of the clinical trials.

Meissner also expressed how thoroughly the CDC panel’s work group on RSV examined the data.

“We went through the details very, very carefully, and I appreciate Dr. [Levi’s] careful review of the records, but the work group is comfortable with the results from the different clesrovimab trials,” he said.

Levi voted against recommending the Merck shot, joined by Pebsworth.

However, the group voted unanimously Thursday that the Merck shot should be included in the Vaccines for Children program, which provides free vaccines to children whose families may not be able to afford them.

HHS spokesperson Andrew Nixon said in a statement Thursday, “The members of this committee are respected experts who take their responsibility to public health seriously. What they did today, just as Secretary Kennedy appointed them to do was review the evidence, debate it with scientific rigor and deliver recommendations rooted in data and medical integrity. The public deserves nothing but this.”

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