My first reaction to the news that the coronavirus seems to have spread more widely than known (eg 20% of NYC residents) was optimism. But my conversations with epidemiologists made me less optimistic.

A thread... (1/x)

Yes, more cases mean that the death rate is lower, and that *is* good news. New data suggest a fatality rate around 0.5% or somewhat higher.
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But there are 2 huge problems:

1. A higher caseload also suggests that the virus is more contagious - and is likely to infect more people more quickly as we re-open and before we have a vaccine.
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2. Even the new, lower estimated fatality rate is dreadfully high. “It is still, with these new findings, many times more deadly than influenza,” as @cmyeaton says. The fatality rate from seasonal influenza is only about 0.1%, not 0.5%.
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Imagine 200m Americans get the virus before a vaccine. That's 1m deaths - which would make the virus the largest killer even of people aged 35 to 64, topping cancer and heart disease, as Zeke Emanuel notes.
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It's always possible unexpected good news will come: a mutation to make the virus less serious, a burst of new treatments, a quick vaccine. But the most likely scenario remains a long, hard slog to beat this virus.
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(More here: https://www.nytimes.com/2020/04/24/opinion/coronavirus-antibodies-test.html)