Actually, the bigger theory is that the vaccines might trigger something genetically. However, there is a huge genetic component to autism.
There are families where the first child had autism. They skipped vaccines for their next children, and their children still had autism.
Mercury is a well known neuro-toxin. The brain is largely neuro-mass. The mercury based preservatives are more effective than alternatives at a significantly reduced cost. It seems to me that this is a "no brainer", so to speak.
On the other hand, we can't have anyone taking action against the medical industry. So, we'll just cover up the facts and have the pharmaceutical companies do some research to prove this connection is bogus.
Business in the US as usual: Make some money at the expense of a few citizens. Oh well, little kids are citizens, too. Judging by the value of unborn ones, young kids can't be worth much. < /sarcasm>