The Centers for Disease Control and Prevention’s vaccine advisory panel, appointed by Health and Human Services Secretary Robert F. Kennedy Jr., delivered a victory for vaccine skeptics in the Make America Healthy Again movement by voting to recommend the removal of influenza vaccines with trace amounts of the mercury-based preservative thimerosal.

The seven members of the Advisory Committee on Immunization Practices, whom Kennedy hired two weeks ago after firing the original members of the board, voted on Thursday to recommend that children, adults, and pregnant women no longer receive multi-dose influenza vaccines that contain thimerosal.

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Anti-vaccine groups have advocated for the removal of thimerosal from vaccines for decades, on the unsupported claim that thimerosal is linked to autism. But multi-dose influenza vaccines are the only vaccines on the market in the United States that still use trace amounts of thimerosal as a preservative.

All other thimerosal-containing vaccines were removed from the U.S. market in 1999, when the CDC and the American Academy of Pediatrics agreed to remove thimerosal from children’s vaccines as a “precautionary measure” following a sweeping review of mercury levels in food and drugs that caused a panic about childhood exposures to heavy metals. 

The ACIP does not have the official authority to remove products from the market. That authority belongs to the Food and Drug Administration. 

But ACIP’s advice provides critical insight for the CDC’s recommendations that inspire state mandates. ACIP recommendations are also tied to what vaccines are covered by insurance. The committee did vote to uphold the recommendation that all people over the age of six months should receive an annual flu vaccine, ensuring insurance coverage for the yearly vaccinations. 

ACIP’s new chairman, Dr. Martin Kulldorff, said that the potential problem with the use of thimerosal in vaccines has always been that of cumulative exposure, or the build up of thimerosal over multiple vaccines even if the dose is small in each individual vaccine.

“Let’s say a child is exposed to 10 different sources, and then those 10 sources might be small enough that that source, in itself, is not dangerous, but if you then put all 10 together, then it might be dangerous,” said Kulldorff. “It’s a cumulative exposure.” 

Kulldorff on Wednesday during the first portion of the ACIP meeting announced that the committee would be convening a working group to study the cumulative effects of all the vaccines on the childhood immunization schedule, another goal of Kennedy’s Make America Healthy Again agenda.

Dr. Joseph Hibbeln, a former National Institutes of Health neuroscientist, said during debates that the fear over thimerosal is as much of a risk to public health as influenza itself if it prevents people from getting vaccinated. 

“The fear of mercury is substantial, and the fear of mercury in causing people to not get vaccines is a risk in itself, whether the actual molecule is at risk or not,” Hibbeln said. “We have to respect the fear of mercury as a potential toxin to avoid people getting vaccines.”

Hibbeln said following his vote supporting the thimerosal’s removal that vaccine manufacturers should be encouraged to use other preservatives in their multi-dose flu vaccines.

“There is a significant benefit to the use of multi-dose 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 multi-use vials rather than single-use vials with other better preservatives.”

Only five of the seven committee members voted on the measures to remove thimerosal. 

Vicky Pebsworth was the only abstention from the committee’s votes. She said following votes that she abstained because the recommendation language before the committee assumed that patients should be vaccinated against influenza every year. 

Despite her abstention, Pebsworth said she supported no longer using thimerosal as a vaccine preservative. 

Dr. Cody Meissner, a professor of pediatrics at Dartmouth Medical School, was the only person on the panel to vote against no longer recommending multi-dose flu vaccines containing thimerosal. Meissner sits in the CDC’s working group, evaluating influenza vaccines. 

“This is an old issue that has been addressed in the past,” said Meissner, adding later, “Of all the issues that I think ACIP needs to focus on, this is not a big issue.”