Healthy Returns: What to know about a CDC vaccine panel’s votes against a mercury preservative in flu shots

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A revamped government panel of vaccine advisors with newly appointed immunization skeptics has voted against a mercury-containing shot ingredient that the anti-vaccine movement has long targeted.

The group, called the Advisory Committee on Immunization Practices, or ACIP, voted Thursday to recommend annual single-dose flu vaccines to Americans and against influenza shots containing thimerosal – even though there is no evidence of harm from that preservative. It was the first ACIP meeting since Health and Human Services Secretary Robert F. Kennedy Jr. gutted the panel and stacked it with new members, including several well-known vaccine skeptics. 

The Centers for Disease Control and Prevention still needs to sign off on that recommendation. If the agency does, it would affect roughly 4% to 5% of the U.S. flu vaccine supply. 

The rest of the nation’s flu shots were thimerosal-free during the last season of the virus, according to CDC data. But when it comes to vaccinating an entire country, “small percentages matter,” Dr. Sean O’Leary, an infectious disease expert with the American Academy of Pediatrics, told reporters last week. 

If the few thimerosal-containing flu shots were removed from the market, 

“that would inevitably lead to fewer people being vaccinated, at least in the short term, perhaps longer term, and subsequently more hospitalizations and deaths,” O’Leary said. 

The recommendation also reinforces longstanding, unfounded fears that the substance can lead to developmental disabilities, such as autism. Kennedy’s vaccine skepticism comes full circle with the panel’s vote: A decade before stepping into his current role, he published a book that called for the removal of thimerosal from shots and linked it to developmental disorders. 

“A very common anti-vaccine talking point is around thimerosal, so that’s a very clear strategy to sow distrust in vaccines,” O’Leary said. 

Here’s why thimerosal is important. It has been widely used for decades as a preservative to prevent the growth of harmful bacteria in several medicines and vaccines with multiple doses. More than 40 studies over many decades have found no link between thimerosal and developmental delays.

But its use in approved vaccines has dropped sharply as manufacturers have shifted to single-dose packaging for their shots, which doesn’t require preservatives. The Food and Drug Administration around 25 years ago asked manufacturers to remove the substance from childhood vaccines out of an abundance of caution, not because of evidence of harm, according to the CDC. 

“The thought was, well, mercury is a scary sounding word, and let’s just get it out, let’s just make this a non-issue,” O’Learly said. He added that “many studies have shown that it is entirely safe, is not associated with any neurodevelopmental disorders or any other adverse effects.”

Some multi-dose forms of flu vaccines for adults still contain thimerosal, including Sanofi’s Fluzone and two shots from biotech company CSL Seqirus. 

One member of the panel, Dr. Cody Meissner, a professor of pediatrics at the Dartmouth Geisel School of Medicine, said he was worried that discouraging the use of multidose vials could increase the cost of vaccination and limit access for some groups. He also expressed concerns about the message the recommendation would send to other countries where the use of multi-dose flu vaccines is more common.

“That might limit the availability of the influenza vaccine for some people,” he said during the meeting after he voted against restricting thimerosal flu vaccines. 

Before the votes at the meeting, Lyn Redwood, a nurse practitioner who has been involved with anti-vaccine organizations, presented on thimerosal in flu vaccines. Redwood is among the “mercury moms” who pushed for Kennedy to get involved with mercury and children’s health. She has also served for years as president of Children’s Health Defense, the anti-vaccine organization founded by Kennedy.

Feel free to send any tips, suggestions, story ideas and data to Annika at [email protected].

Health-care data platform Arcadia has been acquired by the private equity firm Nordic Capital, the companies announced on Tuesday. 

Arcadia turns health-care data into predictive insights that payers and providers can use to help improve care for patients, reduce costs and increase revenue. The company characterized the deal with Nordic Capital as a “strategic partnership” where the firm will become the “majority owner” of Arcadia, according to a release. 

Michael Meucci, Arcadia’s CEO, said working with Nordic Capital will allow Arcadia to continue to improve its customer experience, expand on its artificial intelligence capabilities, explore new M&A opportunities and drive growth in its core segments, including value-based care. 

“It’s hugely validating,” Meucci told CNBC in an interview. “It’s validating that there are large-cap institutional investors who are as committed to transforming us (U.S.?) health care and global health care as we have been.”  

Arcadia and Nordic Capital did not disclose the terms of the acquisition. The deal is expected to close in the second half of the year, though it’s still subject to regulatory approvals. 

Meucci said he’s known the Nordic Capital team for a couple years, and that the firm had been watching Arcadia’s progress as a business. Arcadia is profitable and carried out a successful acquisition last year. Meucci said these milestones helped Nordic Capital feel confident that the company was ready for its next stage of growth. 

Arcadia last raised outside funding in 2023, when it announced $125 million in financing from Vista Credit Partners. Nordic Capital’s acquisition serves as an exit for earlier investors, Arcadia said.

“This partnership aligns seamlessly with Nordic Capital’s investment strategy and Nordic Capital is excited to support Arcadia in its next phase of growth,” Daniel Berglund, partner and co-head of health care at Nordic Capital, said in a statement.

TripleTree served as Nordic Capital’s financial advisor for the transaction, and Lazard advised Arcadia.

“This is just a further reinforcement of our mission, that we have to change the cost of health care,” Meucci said. 

Read the full release here.

Feel free to send any tips, suggestions, story ideas and data to Ashley at [email protected].