A recent study in California should put an end to the assertion that the rise in autism is a result of a mercury preservative used in vaccines. Despite removal of the preservative thimerosal in 2001, the number of autism cases in California has continued to increase.

Commentary: Utilizing a study period from 1995 to 2007, the researchers found that the number of cases of autism continued to grow each year despite the fact that the preservative has not been used since 2001. If thimerosal were indeed the cause, the study should have produced declining autism rates for 2004-2007. Researchers will now likely turn to possible genetic links as the cause though the fact that many children show no signs of autistic behavior for the first year or two of life continues to puzzle experts.