Robert F Kennedy Jr, the US health secretary, will formally require vaccine makers to remove thimerosal from vaccines.
The ingredient has been the target of anti-vaccine campaigns and misinformation for decades. Arguments against the preservative culminated in June, when a key federal vaccine advisory panel, remade with Kennedy’s ideological allies, recommended against the preservative.
The recommendation goes into force upon Kennedy’s signature.
There is no evidence thimerosal has caused harm, despite decades of use. The ethylmercury-based preservative was used in only about 5% adult influenza vaccines in the US, helping prevent contamination in multi-dose vials.
“After more than two decades of delay, this action fulfills a long-overdue promise to protect our most vulnerable populations from unnecessary mercury exposure,” Kennedy said in a statement announcing the decision.
“Injecting any amount of mercury into children when safe, mercury-free alternatives exist defies common sense and public health responsibility. Today, we put safety first,” said Kennedy.
Thimerosal is an ethylmercury-based preservative – different from the kind of mercury found in seafood, called methylmercury. Ethylmercury has a shorter half-life in the body. The amount of ethylmercury contained in a flu vaccine (25 micrograms) is about half of that contained in a 3oz serving of canned tuna fish (40 micrograms).
The preservative has been used in vaccines since before the second world war. It was controversially phased out of most childhood vaccines in 1999, physicians associations said as a precautionary measure, and was contained in only a very small number of adult vaccines.
Phasing out the preservative in the early 2000s was criticized by experts who argued scientific evidence did not support its removal, that it sent mixed messages and that it provided a talking point for anti-vaccine campaigners. Indeed, the preservative was targeted for years to come.
That criticism came to a head in June, after Kennedy fired all 17 members of the Centers for Disease Control and Prevention’s (CDC) advisory committee on immunization practices, a federal panel that was a critical link in the vaccine distribution pipeline.
Kennedy replaced the experts with eight hand-picked allies, including one directly from the anti-vaccine movement. Eventually, one appointee dropped out after a conflict of interest review.
The vaccine advisory panel voted in favor of removing thimerosal on a 5-1 vote (with one abstention) after a controversial presentation from Lyn Redwood, a former leader of World Mercury Project, the predecessor to Kennedy’s group Children’s Health Defense, itself a prolific anti-vaccine campaign group.
Redwood’s presentation had to be updated after it was found to contain a link to a study that did not exist. One of Kennedy’s vaccine advisers said during the meeting that a presentation from career scientists at the CDC, which laid out thimerosal’s safety, was pulled by the secretary’s office.
The director of the CDC is required to sign off on the vaccine advisory committee’s recommendations. Because there is not presently a Senate-confirmed CDC director, Kennedy acts as head of the CDC.
The decision to remove thimerosal from all vaccines in the US will also probably complicate the global picture for vaccine makers.
“With the US now removing mercury from all vaccines, we urge global health authorities to follow this prudent example for the protection of children worldwide,” Kennedy said.
