This panel, appointed by the recently announced presidential candidate, Robert F. Kennedy Jr., did something historic. Specifically, they voted to further restrict the use of thimerosal — an ethylmercury-based preservative commonly used in vaccines, particularly multidose seasonal influenza vials. Quickly during their recent first meeting, the new panel members voted. All of them were ideologically aligned with Kennedy, of course, and they revealed their hand long before the decision came down. The final vote was five in favor of the restriction, one abstention, and one vote opposed.
Thimerosal has an even older pedigree, having been used as a vaccine preservative even before the start of World War II. Where it’s famous for being cost-effective – especially in the case of multidose formulations, which can be cheaper than single-dose formulations. Today, thimerosal is only found in about 5% of the vials of seasonal influenza vaccine.
By comparison, a single flu vaccine contains 25 micrograms of ethylmercury. That’s more than 5 times lower than the 40 micrograms in an average 3 ounce serving of canned tuna fish. Kennedy, one of the US’s most influential vaccine skeptics, has been campaigning against thimerosal for decades. Yet Hung persists, calling for its removal despite a lack of evidence proving real-world harm.
In June, Kennedy dismissed all 17 previous members of the advisory panel, citing conflicts of interest, and replaced them with eight new members who share his views. Besides appearing misguided from the outset, this strategic move cast doubt on the integrity and objectivity of the panel’s decision-making.
During the recent meeting, Lyn Redwood, a nurse practitioner and founder of the World Mercury Project—which served as a precursor to Kennedy’s anti-vaccine advocacy group, Children’s Health Defense—presented her case against thimerosal. Dr. Cody Meissner, Professor of Pediatrics at Dartmouth’s Geisel School of Medicine, was the only one who dared to vote “no” at all and thus to vote against restricting thimerosal.
In response, health authorities in the early 2000s acted by removing thimerosal from all routine pediatric vaccines. They further removed it from most adult vaccines as a precautionary measure. That’s what numerous experts lambasted this decision. They claimed that it was sending mixed messages about a long-used, well-studied preservative that has been shown to be safe. What’s more, multiple studies have consistently failed to show any real-world harm caused by thimerosal.
Dr. Meissner expressed concern about the implications of removing thimerosal from vaccines:
“Removing thimerosal from all vaccines used in other countries, for example, is going to reduce access to these vaccines, it will increase costs, and I think it’s important to note that no study has ever indicated any harm from thimerosal.” – Dr Cody Meissner
Dr. Sean O’Leary pointed out discrepancies between what was presented at the meeting and established scientific consensus:
“There is a very big difference between what was shared at the meeting versus what is reality.” – Dr Sean O’Leary
Dr. Meissner highlighted the greater risk posed by influenza itself compared to any purported risk associated with thimerosal:
“The science on thimerosal is settled, and the rhetoric being used to suggest otherwise is misleading and harmful.” – Dr Sean O’Leary
Opponents of the vote pointed out a very alarming fact. They noted the absence of transparency regarding potential conflicts of interest from the soon-to-be-appointed panel members. None of the members have made written disclosures available to the public. Neither have they shown up on a conflict tracker developed under the Trump administration to the Advisory Committee on Immunization Practices (ACIP).
“The risk from influenza is so much greater than the nonexistent – as far as we know – risk from thimerosal.” – Dr Cody Meissner
The fight over thimerosal has been a go-to talking point for anti-vaccine activists such as Kennedy for years. Most experts say that continuing this debate with no scientific basis hurts efforts to address bigger public health threats.
Dr. Martin Kulldorff defended Redwood’s right to present her views at the meeting:
While vaccine safety will continue to be a hot topic, public health officials are worried that false information will influence individuals and communities from pursuing vaccines. For this reason, experts warn that access to vaccines cannot come at the expense of baseless concerns about preservatives.
“It’s inappropriate to dismiss a presentation just because the person does not have a PhD or MD.” – Dr Martin Kulldorff
As discussions about vaccine safety continue, public health officials express concern that misinformation may hinder vaccination efforts. Experts stress that access to vaccines should not be compromised by unfounded fears over preservatives.