the worlds population in 1918 was 1 billon the spanish flue liamed 100 millon victems worldwide
most vitems of it were healthy beore the cthe cought it.
unlike covid were most people who cought it were at deaths door in the first place.
I think the population in 1918 was more like 1.8 billion. Estimates of deaths vary with 100 million at the top end. About 3% of the world's population.
Again can you not see the folly with your argument above? Most might well have been healthy before they caught Spanish flu but that's because many other diseases that have been either totally eradicated or are treatable today would have killed them before Spanish flu so you were left with the 'fighting fit'.
The reason the elderly and immunosupressed are vulnerable to covid is that other diseases they would have been susceptible to in 1918 would have killed them off before Spanish flu had a chance.
How many of the world's population do you think survived heart attacks, strokes and cancer in 1918 not forgetting all the other diseases?