The idea that autism is caused by vaccinations has been floating around in the media recently. The first episode of the television series Eli Stone revolved around the issue (NY Times) and recently I saw an episode of Larry King Live in which Jenny McCarthy very aggressively asserted a strong link between vaccinations and various health problems, including autism.
Let me say up front that I support additional research on autism, and I don't reject out of hand a possible link between the two. However, I got the impression from McCarthy's behavior on Larry King that the case is already closed in her mind. That's troubling, because the issue has wide-reaching public policy implication. And the science is by no means clearcut, as shown by a recent article in The Economist.
The article provides some evidence that the increase in autism diagnosis rates are not just because autism is on the rise. It's also because there is an increased awareness of the disease and therefore fewer misdiagnoses of autism as something else (e.g., a specific language impairment, for example). In other words, it isn't necessarily the case that autism is skyrocketting. Maybe doctors are just getting better at recognizing it. (It's an open question.)
But the bigger problem is that, if it can be established definitely that vaccinations cause autism in some cases, and there is no way of changing the vaccinations to reduce this risk (say, by eliminating some harmful ingredient), there is still a cost-benefits trade-off between the potential harm caused by vaccinating children and the potential harm caused by not vaccinating them, as Jenny McCarthy herself acknowledged (albeit in a somewhat simple-minded fashion) when she said, "An increase in the measles, I'll take that way over autism any day." But it's not just measles. It's hepatitis, tetanus, diphtheria, measles, smallpox, and polio (among others). Is the potential threat of autism so great that we're willing to put up with more children contracting these diseases instead? I guess that's the $64,000 question.