1) Researchers are getting better and better at recognizing autism in children at a very early age. For example, abnormal or accelerated head growth is often found to occur before classic autism symptoms appear. Analysis of home videos of very young children is also getting better at recognizing subtle signs of autism in babies as young as 6 to 12 months old. Both of these methods detect autism before vaccinations occur. There is no reason to think that the problem starts after vaccinations.
2) Researchers in Britain realized that if children become autistic because they had a bad reaction to the MMR (measles mumps rubella) shot, then some sign of an abnormal immune response (such as increased antibody levels) would be present in the blood of the children with autism. Their study found no such abnormalities.
3) A recent study showed that the type of mercury that used to be found in vaccines clears out of the body about ten times faster than previously thought, so there is no cumulative build-up of mercury from one vaccine to the next. Accumulation of mercury was one of the biggest fears with those vaccines.
4) Finally, for those who thought the mercury-containing Thimersol was causing autism—nope. Pharmaceutical companies stopped using Thimersol for the most part in 2001. The people fighting against Thimersol thought the number of autism cases would drop off dramatically when this happened, but there hasn’t been any slowing down at all. A new study shows no drop in reported autism cases since 2001 (Schechter R and JK Grether (2008). Continuing Increases in Autism Reported to California’s Developmental Services System. Arch. Gen. Psychiatry 65: 19-24.)
Maybe there is something other than a genetic cause of autism, though I’m not aware of any good candidates. It is becoming more obvious that vaccines have nothing to do with it. A person would be putting his or her child at risk by not getting the kid vaccinated. Thanks to the Neurologica blog for 3/4 of this information.