Decades of research show the mercury-containing preservative thimerosal is safe in vaccines, but CDC's new advisory panel is ...

Advisers to the Centers for Disease Control and Prevention recommended against flu shots containing the ingredient thimerosal ...

The CDC panel voted against an ingredient that the anti-vaccine movement has long targeted, while Arcadia was acquired by private equity firm Nordic Capital.

If the agency does, it would affect roughly 4% to 5% of the U.S. flu vaccine supply. The rest of the nation's flu shots were thimerosal-free during the last season of the virus, according to CDC data.

Mercury-based preservative thimerosal is in the spotlight, as a CDC committee votes to recommend single-dose flu vaccines without the controversial ingredient for all age groups.