..., and in fact vaccines had more mercury in them then (which many believe can be an autism trigger--again, I haven't seen data to back that up).
There are some similarities between mercury poisoning and autism, but there are also very large difference, there is no reason to link them together.
The mercury in vaccines was bound up in a compound call thimerosol(?). This is a form that is easily passed, it does not build up in the tissues.