backtotalkaboutthis , your comments re: why Andrew Wakefield 'study' was discredited just seem to confirm how little some people know about case and effect, correlation and causation.
The investigation into Andrew Wakefield had little to do with the results he 'presented' (heterogeneous sample of 12 was far too small to make any suggestion of correlation between vaccs and the symptoms, much less the conclusions drawn).
The investigation was due to highly unethical behaviour, including not gaining ethical approval, dishonesty and consent issues.
The ethical way of looking at this is via large scale observational studies (preferably prospective), as the development of autism/adverse vacc effects are rare.
There is an epidemiological study here: www.bmj.com/cgi/content/full/325/7361/419
It considers data from a very reputable source, from 211 480 children over 11 years; out of these, 66 had definite autism, 30 possible autism...so you can see what a rare outcome this is generally for children born in those years. These 96 were no more likely to have GI symptoms than the matched controls. This study refers back to other studies that are also large and show no increase in autism due to introduction of MMR.
www.bmj.com/cgi/content/full/325/7361/419 is another large study (active surveillance in the UK), that looks at the new vaccine vs. old.
Does this answer the vaccination issues raised in this thread? No...this is more to show the difficulties of conducting valid research, because the incidence of autism and vaccination related adverse events is so small.
Does that mean that they don't exist? Of course it does not mean adverse events due to vaccination do not exist, or that they are not serious - as others have stated, they can be devestating for the families concerned....but so are the effects of the diseases.