ATLANTA — A panel of vaccine advisers selected by Health Secretary Robert F. Kennedy Jr. voted Thursday to recommend that no one get a flu vaccine that contains thimerosal — a preservative that has long been a target of the anti-vaccine movement and Kennedy himself.
Five members voted to recommend that no children, pregnant women, or adults get any flu vaccine with thimerosal. If the CDC adopts the recommendation, it will mark one of the first major changes in federal vaccine guidance and access as Kennedy embarks on his goal of remaking immunization policy in his image.
Concerns Over Thimerosal
“The risk from influenza is so much greater than the nonexistent, as far as we know, risk from thimerosal,” said Dr. Cody Meissner, the only panel member who voted no. “I would hate for a person not to receive the influenza vaccine because the only available preparation is with thimerosal.”
The CDC director usually needs to endorse the recommendations before they are official. But Kennedy will likely be the one to endorse these recommendations because there is currently no CDC director or acting director.
The decision came after a presentation from Lyn Redwood, a former president of the Kennedy-founded anti-vaccine group Children’s Health Defense, who identified herself as a “private citizen.” The Washington Post reported Wednesday that Kennedy had hired Redwood to work in the CDC’s vaccine safety office.
The HHS directory lists Redwood as an “expert” in the Office of the Assistant Secretary for Health. Department spokespeople and Redwood didn’t respond to requests for comment on Redwood’s role.
Redwood’s presentation largely argued that thimerosal, a preservative that has been used in vaccines since the 1930s, should be removed from the products because of safety concerns.
The CDC website says that there is “no evidence of harm caused by the low doses of thimerosal in vaccines, except for minor reactions like redness and swelling at the injection site.”
A CDC background document for members of the Advisory Committee on Immunization Practices, posted by the agency on Tuesday and later removed from its website, also diverges from Redwood’s conclusion, arguing there is overwhelming evidence that thimerosal-containing vaccines do not cause neurological problems. ACIP member Dr. Robert Malone said the document was removed because “it was not authorized by the office of the secretary.”
Redwood’s presentation argued there is evidence that thimerosal can cause serious complications, especially for pregnant women.
“The fact that thimerosal from vaccines has been documented to raise blood mercury levels over known thresholds where developmental effects have been documented to occur during the first few months of life, means that particular ‘windows of vulnerability’ may have been breached,” Redwood said.
Thimerosal continues to be used as a preservative in multi-dose vaccine vials to inhibit germ growth, but the vast majority of FDA-licensed flu vaccines are already thimerosal-free — 96 percent of all flu vaccines in the U.S. last season didn’t contain the preservative, according to the CDC document removed from the website. It was largely removed from childhood vaccines in 2001, and several pediatric products — including the measles, mumps and rubella and varicella shots — never included the ingredient.
In 1999, the FDA and CDC announced plans to work with manufacturers to reduce or remove thimerosal from vaccines. But the move was a precautionary measure, and further research has identified no link between the ingredient and neurological defects.
Several ACIP members agreed with Redwood, including committee Chair Martin Kulldorff, who argued that while the level of thimerosal in vaccines may be safe, it could contribute to high cumulative mercury exposure.
But Meissner, a pediatrics professor at Dartmouth College’s medical school, pushed back strongly against Redwood’s assertion.
“I’m not quite sure how to respond to this presentation,” Meissner said. He went on to note that thimerosal is metabolized into ethylmercury and thiosalicylate, not methylmercury, which is found in fish and shellfish and is highly toxic to humans.
“Ethylmercury is excreted much more quickly from the body, and is not associated with the high neurotoxicity that methylmercury has,” Meissner noted.
“Of all the issues that I think ACIP needs to focus on, this is not a big issue,” he added.
Many public health experts on the call also pushed back.
Jason Goldman of the American College of Physicians asked whether the committee would get an “actual CDC presentation done by staff, scientists, physicians and those who are subject matter experts with accurate, peer-reviewed scientific data or the ability for the committee to review [the data]” or if they would just hear “layperson presentations.”
Separately, the panel also recommended the updated influenza vaccine for the upcoming fall and winter season. Six members voted to approve, while Vicky Pebsworth, a public health scientist and nurse who’s served on the board of an anti-vaccine group, abstained.
Members of the press were not allowed to leave the press area, largely preventing them from speaking with the members of the committee. Kulldorff declined to answer questions following the meeting.
“This committee strongly supports the use of vaccines and other counter measures predicated on evidence-based medicine, including rigorous evaluation and expansive credible scientific data for both safety and efficacy,” the committee said in a statement after the meeting concluded. “All stakeholders, including healthcare providers, parents, children, schools, nursing homes, insurance providers, public health agencies, manufacturers and the rare few who may be harmed by recommended interventions need to have understandable, digestible, scientifically correct information.”
The CDC’s vaccine advisory committee may consider at its next meeting a proposal to advise against giving a combination shot against measles and chickenpox to children under 4, Kulldorff said Thursday after delivering a presentation on the product.
Under the current childhood immunization schedule, the CDC recommends that children receive two doses of the measles, mumps and rubella vaccine and the varicella vaccine — the first between 12 and 15 months and the second between 4 and 6 years of age. An MMR-chickenpox combination vaccine, known as MMRV, may be used, but the agency advises that the first dose be administered as two separate shots.
ACIP updated its recommendation in 2009 to recommend separate MMR and varicella vaccinations for younger children due to an increased risk of febrile seizures in children under 2 who received the combination shot compared with those who got the two distinct vaccines. Fever-induced seizures are common in young children — the CDC estimates the risk at 5 percent — but don’t cause permanent harm.
“A proposed recommendation — we’re not going to vote on that this time, but possibly at the next meeting — could be that, as there exists a safer, equally effective alternative, the MMRV vaccine should not be administered to children under the age of 47 months,” Kulldorff said.
