WASHINGTON, D.C.: Federal officials say the U.S. will no longer distribute flu shots containing the mercury-based preservative thimerosal, a policy shift directed by Health Secretary Robert F. Kennedy Jr.

The move follows a vote last month by a vaccine advisory panel whose members were selected by Kennedy. The panel recommended that only thimerosal-free flu vaccines be offered to Americans, despite long-standing scientific consensus that the preservative poses no health risk. Kennedy accepted the recommendation, according to the Department of Health and Human Services.

Thimerosal has been a target of vaccine skeptics for years, with claims that it causes autism and other neurodevelopmental disorders—claims that public health agencies and multiple studies have consistently rejected. The U.S. Food and Drug Administration states on its website that thimerosal has not been shown to be dangerous in vaccines, and that earlier decisions to remove it were precautionary.

Roughly 5 percent of flu shots in the last season contained thimerosal, primarily in multi-dose vials. Most vaccines today are packaged in single-dose syringes that don't require preservatives, but some manufacturers still produce multi-dose versions with thimerosal.

A panel member who voted against the recommendation warned that the potential harm of deterring people from getting vaccinated outweighed any theoretical risk from the preservative. "The risk of not receiving the influenza vaccine because it contains thimerosal is greater than any known risks of the preservative," the panelist said.

Still, the panel's majority decision stood. With Kennedy's endorsement, the Health and Human Services department confirmed the new guidance would be implemented, even though the Centers for Disease Control and Prevention (CDC) has not signed off. The CDC director — a role typically responsible for final approval — remains unconfirmed, with President Donald Trump's nominee, Susan Monarez, still awaiting Senate confirmation.

Kennedy, a longtime critic of vaccine ingredients, authored a book in 2014 calling for the "immediate removal of mercury" from all vaccines. This latest step marks a significant shift in U.S. vaccine policy under his leadership.

Manufacturers have said they can accommodate the change without disrupting supply. Sanofi confirmed it will have an adequate inventory of thimerosal-free vaccines this flu season. CSL, another major producer of influenza vaccines, has not yet responded publicly.

The HHS added that other vaccine-related recommendations from the advisory committee's June meeting remain under review.

For now, Kennedy's decision signals a broader re-evaluation of long-standing immunisation practices, even as public health experts warn against moves that could undermine confidence in vaccines.