Dr. Lucky Tran 
The “problem” with vaccines? They so effective at preventing deaths that they create generations of people that question whether disease was a problem in the first place because they have never experienced the horrors of a world without vaccines.
recursive 🏳️🌈@luckytran conceptually I think this is like Kondratieff cycles
Or any other concept for "the people who experienced it are no longer here to tell us what it was like" (and we don't believe written records in the same ways — admittedly for sometimes good reasons)
My grandparents saw the last widespread victims of polio among their children (who were too young to understand it as being as terrible as it is). The last of those grandparents died in 2011
My uncle was one of the only victims of polio I have known closely, born in 1938 (died fairly young in 2002)