Sounds like an excellent point

 I didn't know that about polio - so I assume most people wouldn't.

I also see on Twitter that the come back to this by COVID anti-vaxxers is "but the COVID vaccine is not a normal vaccine!  It's new and untried and you have to keep getting boosters..etc etc".

I've said it before, and say it again:   a significant chunk of the Right has spent 20 to 30 years telling each other that there's a massive conspiracy in the scientific community (in the form of climate change.)

Having become so acclimatised to believing one massive conspiracy, they find it easy to swallow another conspiracy that is also actually against their children's interest to believe.