Last month, the restructured ACIP voted 5-1 with one abstention to recommend that children, pregnant women, and all other adults use only single-dose seasonal influenza vaccines without thimerosal. That vote came after Kennedy removed all 17 members of ACIP earlier in the month and handpicked a group of replacements.

While few shots still contain thimerosal, the move eliminates a vaccine option for Americans and is a win for the anti-vaccine movement.

Although it has been largely phased out of U.S. vaccines, thimerosal has long been targeted by anti-vaccine advocates.