Robert F. Kennedy Jr., the U.S. The Health Secretary has taken a dramatic step that’s sending shockwaves through the medical and global public health communities: he is officially banning the use of thimerosal, a mercury-based preservative, in all vaccines administered in the United States.
The move marks the fulfillment of a decades-long mission for Kennedy, one that has placed him at the center of vaccine-related controversy. While health authorities worldwide have repeatedly stated that thimerosal is safe, Kennedy, long known for his skepticism toward vaccine safety, says it’s time to prioritize caution over consensus.
🚨Breaking: RFK Jr. has officially ordered thimerosal—a mercury-based preservative—removed from all flu vaccines in the U.S. pic.twitter.com/bZwHC839mf
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“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. “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.”
The decision goes into effect immediately following Kennedy’s signature, after the CDC’s Advisory Committee on Immunization Practices (ACIP) voted to recommend the removal of thimerosal. That panel had recently undergone a major shake-up—Kennedy fired all 17 previous members and replaced them with eight hand-picked appointees, including at least one individual tied to the anti-vaccine movement.
The vote passed 5-1, with one abstention, despite concerns over the credibility of a presentation from Lyn Redwood, a former leader of the World Mercury Project. Her presentation initially cited a non-existent study and had to be edited. Meanwhile, a scheduled presentation by CDC scientists defending thimerosal’s safety was allegedly pulled by Kennedy’s office, drawing accusations of bias and censorship.
Thimerosal, an ethylmercury-based compound, has been used since before World War II to prevent contamination in multi-dose vaccine vials. Though it contains mercury, it’s a different kind, ethylmercury, not to be confused with the more harmful methylmercury found in seafood.
Despite its long history and relatively limited use, found in only about 5% of adult flu vaccines today, thimerosal has been at the center of anti-vaccine campaigns for decades. Scientific reviews have repeatedly concluded that it poses no threat to human health; however, critics have interpreted its removal from most childhood vaccines in 1999 as a concession to public fears.
Public health experts had warned that phasing it out entirely might signal to the public that thimerosal had been dangerous all along, further fueling misinformation. And yet, Kennedy’s move suggests that symbolism is part of the strategy.
The decision may also have global implications. Many low- and middle-income countries still rely on thimerosal-containing vaccines because they are cost-effective and easier to distribute. Kennedy’s directive puts pressure on global health organizations to follow suit, regardless of the scientific consensus.
“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.
However, many scientists remain alarmed, not because thimerosal is being removed, but because of how the decision was made. The CDC currently lacks a Senate-confirmed director, meaning Kennedy has de facto authority over the agency. His critics argue that this move bypassed established scientific review processes, thereby opening the door to politicized public health decisions.
Still, to Kennedy’s supporters, the decision is long overdue. They see it as a victory for transparency, caution, and consumer choice. But for the broader scientific community, it’s a troubling precedent, one where political ideology may be eclipsing decades of research.
It is yet to be seen how the move will impact the effectiveness of vaccines when alternative methods become the norm.
