> I think people were a little smarter about vaccines when polio vaccine became available.

The important thing is that everyone at that time knew someone who had complications from polio, some mild, some severe. This made them eager to line up for the vaccine when it became available. My uncle had a lifelong limp from polio, and considered himself lucky that it was just a limp and he lived a pretty much normal life. Same with Mitch McConnell, and forgetting whatever you think of his politics, is a polio survivor with some lifelong consequences (frequently falls on stairs, e.g.) and has never been an anti-vaxxer.

People today often don't know anyone who has had serious aftereffects from preventable diseases. Measles is a case in point. I am in my 60's and had measles as a young child way before there was a vaccine. Almost every child had measles at some point. I can still remember the high fever and I remember my eyes hurting a lot (might have had swelling or something) and my mom putting cold wet cloths over my eyes. As an adult I realized how lucky I was that that was the worst of it. My mom told me that one child in the neighborhood died from encephalitis caused by the measles.

The anti-vaxxers are giddy in their ignorance, and actually believe measles is a nothingburger that every child sails through in a few days. They bizarrely believe that the vaccine is more dangerous than the disease. I wish they would stop reading nonsense from weird woo sources and read some facts, such as measles having been a major cause of deafness in my day.