'A mercury-containing preservative should not be banned as an ingredient in vaccines, U.S. pediatricians said Monday, in a move that may be controversial.

In its statement, the American Academy of Pediatrics (AAP) endorsed calls from a World Health Organization (WHO) committee that the preservative, thimerosal, not be considered a hazardous source of mercury that could be banned by the United Nations.

Back in 1999, a concern that kids receiving multiple shots containing thimerosal might get too much mercury - and develop autism or other neurodevelopmental problems as a result - led the AAP to call for its removal, despite the lack of hard evidence at the time.'

Read more: Keep Thimerosal in Vaccines: Pediatricians