Originally Posted by ma2two
So since they can't do the absolute gold standard of a randomized, double blind placebo controlled study with unvaccinated children, they shouldn't do any studies at all, it seems.
But it also seems they have no problem doing other types of studies, as long as they don't include a group of completely unvaccinated children.
And at the opposite end, why aren't there studies looking at children who were healthy and developing normally, and then regressed after vaccination? To try to figure out what is different about them, from children who seemed to do well after vaccination? The late Dr. Bernadine Healy said such studies hadn't been done, but should be done. They still haven't been done.
By "regressed," do you mean that they began to display autistic symptoms? It is known that autism commonly manifests before the age of 2 years.old, regardless of whether the child is fully, partially, or not at all vaccinated. It is apparently a coincidence that this also happens to be around the time at which a number of vaccines are provided. As I said, there is no scientific evidence that vaccines cause autism, despite numerous rigorous studies.
I've stated why an experimental study (random controlled trial) is unethical. It sounds like you want an observational study instead, which is generally less useful but can still be interesting. There can be some problems with this. For example, the number of unvaccinated children is relatively small, and within that group, the children tend to have homogenous backgrounds - they tend to be white, have married mothers with college degrees, live in an upper middle class household, etc. One of the keys to an effective study is having a heterogeneous group to study, which would be tough to put together here. But some attempts have been made, in fact one of them was by anti-vaccination group Generation Rescue. The study, which I would call poorly done and unreliable, found that the highest incidence of autism was in partially vaccinated children (with lower incidence in fully vaccinated children) which would actually appear to be evidence against vaccines causing autism. I can't find a direct link to the study any more, but you can read an analysis at http://web.archive.org/web/20080116035729/http://www.kevinleitch.co.uk/wp/?p=567.
Just to go back to the issue of the small number of unvaccinated children for a second... the estimate in the US is that somewhere around 50,000 3-6 year olds are completely unvaccinated. If you could enroll 1% of them in a study (even 1% could be tough), the study would only be able to reliably detect around a 15-fold difference in autism rates. If it were "only" a difference of five times, you couldn't see it in that study. You could do a study to detect a more reasonable 10%+ increase in autism rates with vaccination - if you had three times as many unvaccinated children in the study as there are in the entire country. This is an inconvenient problem, but it's how statistics works. You might be able to bypass it somewhat by doing several studies around the world, but this would get very complicated, very expensive, and divert money from researching more promising areas related to things like autism. Areas where there is more evidence for a cause. That's why you aren't seeing these studies.