One of the points that anti-vaccine proponents keep bringing up is how autism prevalence has been going up over the past few decades. They notice how autism diagnoses have gone up and correlate that with an expanded vaccine schedule, then finally make the leap to imply it was the vaccines that caused autism. When we say that an expanded definition and expanded surveillance is what has in big part resulted in the increase, they laugh it off. That is not possible, they say; the increase must be a real increase of actual cases.
Recently, a new study came out of South Korea. It was a 5 year study that looked at all children in a South Korean community, not just high risk kids, or those that went to the doctor. They found an Autism Spectrum Disorder (ASD) prevalence rate of 2.6%. By comparison the current rate is estimated to be 1/110 or 0.9%. By looking at all children, vs. just those in the high risk groups, as has been the practice generally, the prevalence rate almost tripled.
Wednesday, May 18, 2011
Quite often people will use the argument that autism rates have increased dramatically as a result of vaccines. The proposed mechanism for this increase has been bandied about, and the anti-vax pro-disease contingent can't get their act together on this. The insistence that Thimerosal was supposed to be the cause, yet rates have continued to climb, even though vaccines have been free of Thimerosal for a decade is of no matter (or the really embarrassing fact that MMR vaccines never contained Thimerosal to start with!). So this study on autism itself was interesting.