I was thinking that for next time I would be checking about the thiomersal, but have had my questions answered here. I don't have experience with autism, but it is something I have researched a fair bit, as I wanted to have all the info before immunising. I have immunised both girls and will immunise again, but I like to know what is going in them first. Unfortunately it seems to be like allergies (we've just found out DD has nut allergy as well as egg) and no one can tell you how or why, or what to avoid or what to do to prevent. It's all a bit of a shot in the dark. Even though I know many parents of autistic children will say it's the vaccine and I dont think you can argue with a mothers intuition. So I think it comes down to your intuition and what you think is best.
I do have to add that I am glad to have immunised. I have a friend who didnt' start the whole process until 2 years not 2 months (thought he might be better equiped at that age, and there are natural remedies that can help with immunity. )
Saying all that, I wouldn't want to not immunise and then my child catches something that could've been prevented. Alot to weigh up I guess, so good luck! xoxoxo