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Why COVID-19 Deaths Aren’t The Best Measure of Flattening the Curve
You might have noticed a contradiction: Everyone is saying that the curve is flattening, yet the death rate in the U.S. shot up yesterday. This might make it seem like it’s not working.
Relax. (Okay, it’s terrible, but…)
Why the Death Rate Isn’t a Good Early Indicator
It’s simple.
The incubation period of COVID-19 is 2 to 14 days with occasional outliers. The average is 5 to 6 days.
The typical period from symptom onset to death seems to be about two weeks.
So, people who died yesterday could have been exposed a month or more ago. The fatality curve is going to lag the case curve by about two weeks (all of this has a lot of variation, but we’re sadly dealing with fairly large numbers here.
What Should We Look at Instead?
The primary thing public health people are looking at is new confirmed cases per day.
If we look at that for New York, then the number of confirmed cases (and that’s with improved testing) peaked on April 4, with a second lower peak on about April 8. It’s declined since, although it’s a ragged chart with peaks and valleys. Fewer tests are being processed on…