You do know the current COVID strain and Spanish flu are not the same thing right? And that what may have worked then (50 million dead people might question your definition of "worked"), might not work now? And as we've already established the situations in 1918 and now are incomparable?Not only did I read and digest it the first time, I've had the very same professor spouting his ambiguities over the airwaves every 30 mins on R6 new bulletins in the background all day.
Here are some question for you - if natural immunity lasts only for a matter of months for everyone and CV just keeps coming back, how come we don't see loads of people die of Spanish flu all the time? Or do we (and they just call it normal flu)? Why did Spanish or Asian flu rip round the world in a couple of years, never to really return in significant numbers in the days before flu vaccines? If long term herd immunity wasn't a significant thing, surely they would have just kept coming back ad infinitum?