Thimerosal in vaccines has no link to autism

NEW YORK (Reuters Health) - Exposure to thimerosal, a mercury-containing chemical previously used as a preservative in vaccines, does not increase the risk of autism, according to a report in the American Journal of Medical Genetics.

"Fierce debate" continues over whether thimerosal exposure raises the risk of autism, the authors point out. In the last two decades, there has been a rise in autism cases, which coincided with increased usage of vaccines containing thimerosal. Although studies have shown no evidence of an association, thimerosal was removed from all routine childhood vaccines in the U.S. in 2002.

The present study involved a telephone survey of 214 mothers of 230 children with autism or a related disorder. Exposure to thimerosal-containing Rh immune globulin, a vaccine administered to some women to avoid pregnancy complications, was compared between this group and the general population.

The researchers found that autistic children were no more likely than unaffected children to have been exposed to Rh immune globulin, lead author Dr. Judith Miles, from the University of Missouri-Columbia, and colleagues report.

These findings provide more evidence that childhood autism is not caused by thimerosal, the authors conclude. They hope this report will encourage all parents to adhere to immunization recommendations. A lack of compliance is known to increase the risk of serious complications and death in children who may contract infectious diseases.

SOURCE: American Journal of Medical Genetics, May 16th online issue, 2007.