Italian study regarding vaccines, autism and mercury poisoning

For some time, there has been a brutal disagreement over whether mercury in older vaccinations caused or contributed to the development of autism in children.  Parents of afflicted children and some health care providers swear by the connection, based primarily on the timing of the development of the child's symptoms, while many "mainstream" health professionals compare these claims to "holocaust deniers" (that is, they suggest that there is no sound, scientific basis for the attribution of causation).  Some critics have gone so far as to accuse parents who don't innoculate their children of being parasites:  relying upon other families to protect their children from communicable disease.  Needless to say, unfortunately the debate has become something less than civilized.  A new study from Italy appears to support the view of scientists who argue that there is no scientific causation connection.

In the early 1990s, thousands of healthy Italian kids in a whooping cough study were randomly assigned to receive different amounts of the preservative Thimerosal in their routine shots.   Ten years later, 1400 of these kids completed a battery of tests measuring brain function.  Researchers found essentially no difference between the groups, and the only autistic child identified was in the group that received less Thimerosal. 

Italian researchers concluded that together with the results from a number of other studies, this randomized study rules out the argument that Thimerosal in vaccines can cause autism. (Thimerosal was removed from European vaccinations in 1999 and from American vaccinations in 2001.  Multi-dose vaccinations still contain mercury to prevent contamination.)  Since there was no control group that received no mercury or Thimerosal in vaccinations, the study doesn't rule out every possibility, however, the scientists asked to comment suggested that if there were a connection between Thimerosal and autism, it should have been dosage-related and should have shown up in this or one of the other three peer-reviewed studies on the subject.