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.

The Advisory Committee on Immunization Practices (ACIP), made up of members recently hand-selected by Health and Human Services Secretary Robert F. Kennedy Jr., voted 5-1 on Thursday to recommend against flu vaccines containing the preservative thimerosal.

The preservative is called Thimerosal, and it's included in just 4% of existing flu vaccines, used to help prevent contamination in multi-dose vials. Its use has drawn controversy because it contains a small amount of mercury.