RFK Jr. finalizes ban of vaccine ingredient over debunked health concerns
Washington DC - Robert F. Kennedy Jr.'s Department of Health and Human Services said Wednesday it would end the use of a vaccine ingredient long targeted by anti-science conspiracy theorists over debunked claims it causes autism.
Thimerosal, a preservative that prevents bacterial and fungal contamination in multidose vials, has been extensively studied, with authorities including the World Health Organization finding no evidence of harm.
The move follows a vote by a contested panel handpicked by Kennedy last month that voted to end the use of thimerosal in influenza vaccines for adults, pregnant people, and children.
Although the substance is now rarely used in US vaccines, the recommendations by the influential Advisory Committee on Immunization Practices alarmed experts, who said the move has effectively embedded talking points championed by the anti-vaccine movement into national policy.
While 96% of US flu vaccines in the 2024-2025 season did not contain thimerosal, the preservative remains important in lower-income countries because they are more likely to use lower-cost multidose vials that must be punctured repeatedly, raising the risk of contamination.
Thimerosal contains an artificial form of mercury called ethylmercury that is cleared from the body far more quickly than the form of the chemical found in nature.
A large body of peer-reviewed scientific studies conducted in the US and other countries support the safety of thimerosal-containing vaccines, but US manufacturers voluntarily removed it from most pediatric vaccines in 2001 on a precautionary basis.
WHO vaccine chief reacts to RFK Jr.'s claims
"After more than two decades of delay, this action fulfills a long-overdue promise to protect our most vulnerable populations from unnecessary mercury exposure," RFK Jr. said.
"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."
Vaccine manufacturers have confirmed they have the capacity to replace multi-dose vials containing thimerosal, ensuring supplies will remain uninterrupted, the statement added.
"There is no evidence of harm from the use of thimerosal," WHO vaccine chief Kate O'Brien told reporters last month after the US panel made its recommendations.
"For some of the vaccine supply, this is a very important ingredient in order to assure that we have the doses that are needed to protect children from serious and life-threatening diseases," she added.
Cover photo: Collage: REUTERS