One of the tropes of the antivaccination crusade is that mercury in vaccines cause autism. Of course, this myth of the vaccine deniers is based on several assumptions, all of which are more or less facetious, if not outright fabrications. For example, few vaccines actually contain mercury in the form of thiomersal, and the few that have it (typically, the flu vaccine), have single dose injections that don’t contain it. Furthermore, there is no evidence that thiomersal causes autism. And there is no evidence that children with autism spectrum disorder (ASD) have higher blood or urine levels of mercury. Of course, mercury can cause numerous neurological deficits, but that’s almost always from the methylmercury form, not the ethyl-mercury form (including thiomersal), and certainly not in the tiny quantities delivered in a vaccine.
In a new, and very extensive, study examining the link between environmental mercury, which is usually found in the methylmercury form, and ASD, the results appear to rule out any connection between the two. Basically, the research showed no correlation between high levels consumption of fish, which bioaccumulate methyl mercury, during pregnancy and ASD diagnoses in children. Presumably, if methyl-mercury had a neurological effect on the developing fetus, mothers who consumed a lot of it would have put their children at risk of ASD, if we go with the hypothesis that mercury causes autism. Continue reading “Exposure to mercury does not cause autism–another myth debunked”