There's also an epidemiological study that connects greater incidents of SIDS clustering around vaccination schedules (and when those children actually got vaccines).
Here's a link with lots of studies (a biblio). It's particularly focused on DTaP.
I had this information before I gave my son DTaP (the only vaccine I've given him), and you had better bet that this was weighed in that balance. And, you had also bed that Dh and I vowed to take shifts staying away over-night to watch him and make sure he was breathing all night long. Cosleeping helps, but each of us stayed awake for half the night for two nights straight (that's when the cluster window typically closes (within 2-3 days of vaccination).
Not that it's "causal" -- but it's enough to be a concern to me. I was also watching for other symptoms. Thankfully, no worries.
I also personally believe that autism has many causes, and vaccines may be one of them. But, as a prior poster noted, I think that vaccines are likely part of a confluence of factors, and that this may not be "autism" itself. I know it's a whacked-out theory.
See, I believe that there is a genetic component to the spectrum -- for people truly on the spectrum. I think -- just as there are viruses that mimic other viruses -- there are injuries and behavior patterns that mimic autism.
Thus, the brain-injury plus gut-issues autism spectrum may not actually be "true" autism at all -- and thereby "curable." Whereas, I believe that autism is organic, not injury-based per se, and while therapies of many kinds can help make certain brain pathways to better their social abilities/connect-ability, ultimately their brains process differently (similar to dyslexics).