No autism-vaccine link, panel concludes

A childhood shot and a mercury-based preservative in vaccines are not associated with autism, a U.S. health panel has concluded.

The developmental disorder autism is usually diagnosed about the time children receive their immunizations at age two or three.

The Institute of Medicine in Washington reviewed five large studies that that tracked thousands of children since 2001 and concluded there is no association between autism and the measles, mump, rubella vaccine.

The panel also found no evidence of a link between the preservative thimerosal and autism in laboratory or animal research.

"We strongly support ongoing research to discover the cause or causes of this devastating disorder," said committee chair Dr. Marie McCormick, a professor of maternal and child health at the Harvard School of Public Health.

"Without supporting evidence, the vaccine hypothesis does not hold such promise," she added in a release.

McCormick chaired the panel of experts in pediatrics, family medicine, statistics and epidemiology.

The health panel looked for evidence of a biological explanation of how vaccinations or the preservative could cause autism and found none.

The report's authors weighed epidemiological and clinical studies and listened to advocates and family members who believe vaccines cause autism.

Several studies have found brain differences at birth in autism and the committee said there are opportunities for research that would be "more productive" than continuing to look for a vaccine link.

Tuesday's report updates two previous reports by the panel that determined there was no evidence of an association between MMR vaccine and autism but said there was not enough evidence at the time to determine if thimerosol was associated with autism.