No, from what I’ve read the second wave was the deadliest by far. The first wave being mild. There is anecdotal evidence that sick soldiers spread a virus that became stronger with soldier to soldier spread and then infected more venerable people when returning home. How this would extrapolate to the current outcome I’m not sure.

SARS (including this new Coronavirus) does not mutate as fast as the flu, so it's even less likely to become more deadly than the common flu.

> But SARS has a molecular proofreading system that reduces its mutation rate, and the new coronavirus’s similarity to SARS at the genomic level suggests it does, too. “That makes the mutation rate much, much lower than for flu or HIV,” Farzan said. That lowers the chance that the virus will evolve in some catastrophic way to, say, become significantly more lethal.

https://www.statnews.com/2020/02/04/two-scenarios-if-new-cor...

Right, the swine flu pandemic of 2009 was basically a descendant of Spanish Flu. It continues to circulate, particularly in the last couple years - a majority of flu cases this last couple months have been the H1N1 strain that descends from Spanish Flu. We don't hear about it because newer and more deadly pathogens like COVID-19 have cropped up since.

I think most people in this thread are talking about 1918-1919, though, since that time period's a little more relevant for predicting what COVID-19 will do.