I doubt we'll every know that precisely. People are still trying to figure out how many died from flu in 1918. Here in the US the mortality rate is surely highe

I doubt we'll every know that precisely. People are still trying to figure out how many died from flu in 1918. Here in the US the mortality rate is surely higher than .15 percent. The testing regimen is clearly not counting everyone who's been exposed; it is likely several times higher than the official count. But not yet anywhere close to half the population. And then there are places like Brazil and Mexico, where the disease is clearly rampant and the testing regimens are totally inadequate.