During the 50s, it was common to return to school in the fall, to find out 1 or 2 classmates had died of polio over the summer.
My wife's family still talks about little Buzz, a 5 year old cousin who died of polio in the backseat of his car, as his Dad raced to the hospital. It was in the 50s, and the old folks in the family would talk of it like it was yesterday.
Nobody has had that experience in decades, so people have forgotten about it, and our educational system has been deliberately downgraded so nobody is taught anything important any more.