A new slate of vaccine advisers to the US Centers for Disease Control and Prevention voted Thursday to recommend that Americans receive influenza vaccines that are free of thimerosal even though there is no evidence of harm from the preservative.

Used in very low amounts, thimerosal has been used since the 1930s to prevent contamination in multidose vaccine vials, and in the United States it is used only in multidose flu vaccine vials. The preservative has long been a hot-button topic of anti-vaccine groups, including one led in the past by Kennedy.

Dr. Levi and Vicky Pebsworth, a nurse affiliated with an anti-vaccine group, voted against recommending clesrovimab; the other five members voted yes. After some confusion, the panel also voted to include the antibody in the children’s vaccine program.