Alex Tabarrok gives name to something we’ve all experienced:

Ironically, just as measles can induce immunological amnesia, vaccines can induce social amnesia about the severity of diseases, thereby making society more susceptible to pathogens that they previously were able to resist.

“Vaccine-induced social amnesia” is a good way to describe it. See also: people who ex post claim we never needed covid-19 lockdowns when the truth is in fact the opposite.