The January issue of Archives of General Psychiatry---we labor mightily day and night so that you, dear Reader, do not have to read such stuff---has a nice article reviewing the California data on thimerosal and childhood autism. You may recall that the purported link between thimerosal---a vaccine preservative containing ethylmercury---and autism is one of those conspiratorial fads promoted by the likes of Robert F. Kennedy Jr., and believed with religious fervor by thousands of desperate parents despite the utter absence of systematic evidence showing any such effect.
Anyway, the article reports an examination of the evidence reported by the California Department of Developmental Services. The removal of thimerosal from childhood vaccines was accelerated between 1999 and 2001, and the data report the incidence of diagnosed autism by age and birth cohort from January 1995 through March 31, 2007. The finding? "Since 2004, the absolute increase and rate of increase in DDS clients aged 3 to 5 years with autism were higher than those in DDS clients of the same ages with any eligible condition including autism."
What does that mean? "The DDS data do not show any recent decrease in autism in California despite the exclusion of more than trace levels of thimerosal from nearly all childhood vaccines. The DDS data do not support the hypothesis that exposure to thimerosal during childhopod is a primary cause of autism."
Maybe Bobby the Child now will argue that Californians are just weird. And you know what? He's right.
[cross-posted from www.medicalprogresstoday.com/blog]
As an employee of a division of the DDS, I appreciate that you're one of the few lay people to comment on this that is careful to use "thimerosal" and not "mercury." I have long held that the thimerosal-autism correlation is a statistical coincidence: the developmental skills most glaringly impaired by autism tend to manifest themselves in typically developing children at approximately at the same time as the vaccines are given to them. In this case, these desperate parents and other advocates are clinging to a false positive correlation between vaccination and the incidence of autism.
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