Herd Immunity?
Is that “medical definition” still the same as...December 31, 2020?
;)
I don't understand the question; sorry.
At the beginning of this epidemic epidemiologists said that everyone would be exposed to the virus. Given that, some will seek their own remedies, some will seek medical remedies such as vaccines, some will acquire natural immunity - by means that are not always understood, and some will succumb to the infection.
Originally Sweden did not resort to lock downs and there was no vaccine available. The graph of infections formed a natural bell curve, peaking in about 2 months and diminishing to inconsequential in less than four months. Subsequently the disease held little interest to that population.
In my simplistic view that is classical herd immunity. Certainly medical intervention through drugs and vaccines and whatever else can also play a role.