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 vast majority of research has failed to show any link between thimerosal and autism or other neurological issues.

The overhauled US panel reviewing vaccine data backed the use of only thimerosal-free flu shots for Americans, taking aim at an ingredient that’s long been considered safe by scientists but erroneously linked with autism.