Today, 12:19 PM
Of course I have, but I'm not sure which they you're talking about. The reason that the anti-vax cult has not done any studies is because every time they do, they can't get the results they want. Hence, there's no evidence to support their hypotheses, which in turn leads to the conspiracy theories.
If they are the government, the answer is two-fold. First and foremost, it would be a huge ethical violation to do a double blind study on children that involved intentionally exposing children to various diseases much less intentionally unprotecting half of them.
Second - they do. In this day and age, there are huge populations where the vaccine rates dramatically rises in than a decade, giving researchers the opportunity to watch for things like, say, an increase in autism that coincides with the increase in the percentage of the population vaccinated. No such link has ever been found. At some point a sane person would realize there's a reason for that, while an ideologue simply inserts a conspiracy theory into the conversation.