I wasn't aware 'til I read that article that kids today receive so manyvaccinations. Let's consider the way in which vaccinations work, i.e. triggering a rejection response from the immune system that is expected to last many years, if not a lifetime.
These treatments are given during a crucial developmental period, as the article stated, before two years of age. It's entirely conceivable that there would be effects on those developing systems, depending upon what may be vulnerable to a systematic, repeated activation of the body's own immune system. This then would not arise from a particular ingredient in the vaccine itself but in the body's own response to what medically is termed an "insult".
I suspect that a large proportion of the increase in autism diagnoses is attributable to a greater recognition of this disorder due to better description and more information among clinicians, and to a greater awareness among parents. A substantial portion probably comes as a result of prior misdiagnosis, and others that were previously undiagnosed and unrecognized. It would be interesting to see if there has been a reduction in the diagnoses of other developmental conditions (even ADHD) that corresponded in any way to the increase in autism figures.
If there is a way (unlikely, though, unfortunately) to identify those cases that existed but were undiagnosed, then the remainder could legitimately constitute an increase in occurrence. Nevertheless it should be examined seriously by the medical community.