The epidemic started in China sometime in November or December. The first confirmed U.S. cases included a person who traveled from Wuhan on Jan. 15, and it is likely that the virus entered before that: Tens of thousands of people traveled from Wuhan to the U.S. in December. Existing evidence suggests that the virus is highly transmissible and that the number of infections doubles roughly every three days. An epidemic seed on Jan. 1 implies that by March 9 about six million people in the U.S. would have been infected. As of March 23, according to the Centers for Disease Control and Prevention, there were 499 Covid-19 deaths in the U.S. If our surmise of six million cases is accurate, that’s a mortality rate of 0.01%, assuming a two week lag between infection and death. This is one-tenth of the flu mortality rate of 0.1%. Such a low death rate would be cause for optimism.
Tuesday, April 14, 2020
In case you wondered …
… Is the Coronavirus as Deadly as They Say? - WSJ.
It's important to remember that this editorial, like all of the responsible pieces of science journalism about COVID-19, is a statement of hypothesis, not of fact. The linguistic features of hypothesis are all present: 6 "if...,then..." formulations (several with an implied "then"), 4 uses of "imply/implied", 3 uses of "plausible/plausibly", and a couple uses each of "could", "suggests" and "likely".
ReplyDeleteAs the authors point out, any firm conclusion about infection rate requires widespread, randomized serological testing for antibodies to SARS-COV-2. That work is just beginning and will take months to complete. Without serological data, estimates of death rates, likely case resurgence after loosening of mitigation measures, etc. must remain guesswork. Essential guesswork, but guesswork nonetheless.
It's also worth noting that this editorial was published on March 24 when U.S. deaths stood at about 1500. Today, U.S. deaths exceed 26,000 --- 30% higher than their low estimate for the entire duration of the outbreak in this country.