Health experts were shocked to see that thimerosal, a preservative that has largely been phased out of U.S. vaccines, was on the ACIP agenda.

The CDC's newly rebuilt Advisory Committee on Immunization Practices (ACIP) took aim Thursday at a mercury-based preservative long targeted by vaccine skeptics, recommending that children, pregnant women, and all other adults use only single-dose seasonal influenza vaccines without thimerosal.

Thimerosal, which government agencies and medical experts say is safe, was recommended to no longer be used by Robert F. Kennedy Jr.’s vaccine panel Thursday.