It has a lot to do with him. He doesn't actually have an opinion on any policy issue. For various political reasons, Trump decided to let RFK dictate public health policy according to his extremely delusional ideas. Yes, there was an antivax movement in this country for many years, just as there has been misogyny, racism, and transphobia. Trump has normalized and supercharged all of these moronic and dangerous ideas.

I have not been following measles in Canada, so I can't address that.

See my other comments; it is not possible for RFK to have had any effect on this outbreak. If everyone getting measles was 2 or under, it could be possible; they aren't.

The reason I bring up Canada is as counterevidence; if it was Trump or RFK'S fault, Canada should be doing just fine. They had twice the cases last year in 1/10 the population. The truth is this is a problem with people believing stupid things, and it's going to take a lot more than Trump going out of office to fix.