Your RFK Jr bogeyman doesn’t quite hold water here out in reality
You seem not to have paid attention to the news. Or perhaps the news you watch is incomplete.
The first thing RFK Jr. is doing to make vaccination harder is splitting the MMR vaccine into multiple shots. He wants to do the same with other combination vaccines. Triple the number of shots that kids have to get and you'll reduce the number of kids that get them all.
The second thing is that he's formally rescinding HHS' broad recommendation that all kids get vaccinated, saying that parents and pediatricians should decide on a case by case basis. It's not clear what actual impact this may have. It's possible that it may lead insurance companies to stop covering some vaccines, to play an actuarial game where they refuse to cover vaccines for diseases that are currently rare, until those diseases come back and begin causing enough hospitalizations that vaccines become cheaper. Or that may not happen. We'll have to see.
The splitting of combination vaccines will affect doctor, parent and insurance company decisions, too, since it will increase the pain and cost of fully vaccinating a child.
he has publicly stated that vaccination is the most effective way to prevent measles
RFK Jr. has given the weakest possible recommendation for vaccination for measles. Yes, he has on a couple of occasions grudgingly said it's good, but then quickly reverted to talking about vitamins and whatnot. But I really doubt that public statements have that much effect one way or the other. What matters is policy.
Canada has a far higher number of cases per capita, its health care system is overall teetering over its capacity, and it has yet to fully secure its border.
Canada has a higher number of cases because they presently have a lower vaccination rate but vaccine resistance is isolated to certain pockets of society, not widespread like in the US, so its actually easier for them to work with the holdouts -- and the holdouts are also where all of the cases are focused, so that population has been hit a lot harder, which should help them come around.
The Canadian healthcare system is having issues in some areas, but delivering vaccines is not one of them.
Finally, this issue has nothing to do with immigration, it's all about whether Canadian kids get their shots.