Health Department Eliminates Thimerosal from U.S. Flu Vaccines

Washington, D.C. — The U.S. Department of Health and Human Services (HHS) announced Wednesday that all influenza vaccines distributed in the country will no longer contain thimerosal, a mercury-based preservative. HHS Secretary Robert F. Kennedy Jr. signed this recommendation, originally proposed by the U.S. Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices (ACIP) last month.

“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. He stressed the importance of safety in vaccine administration, stating, “Injecting any amount of mercury into children when safe, mercury-free alternatives exist defies common sense and public health responsibility.”

Thimerosal had been largely phased out of vaccines about 25 years ago due to a precautionary measure rather than clear evidence of harm. According to the CDC, the Food and Drug Administration (FDA) encouraged manufacturers to stop using it, especially in vaccines recommended for young children. Last year, only about 4% of flu vaccines given in the U.S. still contained thimerosal, primarily in multidose vials to prevent bacterial contamination.

In June, the newly appointed ACIP panel, which includes members appointed by Kennedy, voted to recommend that only single-dose flu vaccines, which are thimerosal-free, be administered to children, adults, and pregnant women. The vote passed with a 5-1 majority, with Dr. Cody Meissner being the sole dissenting voice. Dr. Vicky Pebsworth abstained from voting, expressing concerns about the recommendation’s wording.

Meissner, a professor of pediatrics at Dartmouth‘s Geisel School of Medicine, noted, “The risk from influenza is so much greater than the nonexistent — as far as we know — risk from thimerosal.” He worried that favoring single-dose vials could hinder access to the influenza vaccine.

Public health experts also expressed confusion over the inclusion of thimerosal on the agenda, with Dr. Sean O’Leary from Children’s Hospital Colorado stating he was unaware of any pediatric practices using the multidose influenza vaccine.

Despite ACIP’s recommendations, the FDA continues to approve vaccines containing thimerosal, highlighting the influential role ACIP plays in vaccine policy, insurance coverage, and state health regulations. At the same ACIP meeting, six members reaffirmed the recommendation that everyone six months and older receive an annual flu vaccination.