Despite substantial evidence to the contrary, some people believe that vaccines (specifically, trace amounts of mercury in vaccines) cause autism. Apparently John McCain is one of those people. He was quoted this week as saying that the incidence of autism is rising (true, according to the CDC's most recent report), and that "there’s strong evidence that indicates that it’s got to do with a preservative in vaccines."
It just ain't so. That's according to--at least--the Institute of Medicine (report here); researchers at the California Department of Public Health (abstract); and the Centers for Disease Control (ongoing research). And a study reported last month in Pediatrics concluded that babies excrete thimerosal (the mercury-containing preservative in vaccines) more quickly than previously thought.
The NYT suggests that the Senator's claim is designed to garner support from the numerous parents' groups that believe in the thimerosal-autism connection. To further confuse the issue, the Department of Health and Human Services recently agreed to settle a case that alleges that administration of standard childhood immunizations caused illness in a child with a pre-existing mitochondrial abnormality. You can learn more in this New Scientist article.
This isn't to pick on Senator McCain--we're nonpartisan on the blog--but it did make me think about how and why politicians choose sides on controversial issues in science. In that sense, the autism controversy isn't much different from climate change or evolution. If the meta-issue here (politics and science) is of interest to you, check out Sciencedebate 2008--a call for the presidential candidates to share their views on the environment, health and medicine, and science and technology policy.