In mid-February, the growing number of parents of autistic children who insist the condition is triggered by thimerosal, a mercury-laced preservative in vaccines, were dealt a setback when a federal court ruled firmly that, "The evidence . . . has fallen far short of demonstrating such a link [between vaccines and autism]." Rather than settling things, the ruling further enflamed the controversy over whether childhood autism is actually increasing, and if it is, why?
About 1 in 150 American children are now thought to have autism or related conditions such as Asperger's disorder, Rett's disorder, or childhood disintegrative disorder. For the last decade, however, some researchers have contended that there's been no increase in incidence, but rather an increase in diagnosed cases resulting from an expansion of identified disorders on the autistic spectrum, a broadened definition of the symptoms, and better surveillance (see Clinician's Digest, January/
Despite the court's ruling, many parents point out that the time frame of the increased use of thimerosal-infused vaccines roughly paralleled the rise in autism diagnoses. If there's no danger in thimerosal, they ask, why did the government urge manufacturers to discontinue its use in 1999? Today, although the use of thimerosal has been eliminated from some vaccines, it's still prevalent in most flu shots, and both the Centers for Disease Control and the American Association of…