In 1918, almost everyone had been exposed to some type of influenza before, meaning most people could count on a degree of immunity. The result was that the Spanish flu infected only a third of the world’s population. By contrast, no one has any immunity to the new coronavirus—hence the estimates that as much as 80 percent of the world’s population could have been infected by the time the pandemic will have run its course. The greatest reason for concern, though, is that so far, SARS-CoV-2 appears to kill about 2 percent of confirmed cases. That is a very similar mortality rate to the Spanish flu.
‘A Once-in-a-Century Pathogen’: The 1918 Pandemic & This One
