This is unclear … this thing may be burning itself out in NYC naturally:
I wonder what the true exposure rate on the Diamond Princess was. About 20% of the people on board tested positive for virus, but that’s not definitive for exposure, since there’s a window in the illness for testing — outside of this window, people don’t test positive unless the swab is done exactly right. It could be nearly 100% exposure and antibodies for all we know. I would love to see a serological survey of all of the passengers on the Princess.
12 people died out of 3700, which means the infection fatality rate could be 0.3%, even with an average population age of 58. Extrapolating this to NY state’s expected 16000 deaths, and assuming a true infection/exposure fatality rate of something like 0.15% to account for a lower average age of 37-38, 10 million people may already be exposed, which means that we’re 2/3 of the way to herd immunity.
The DP incident isn’t a large enough sample to be definative, but it make me wonder if cases in NYC are now slowing because half the state (and probably more than half of the city) are dead-end hosts at this point in time.
If this thing started out with an R0 number of 3.0, 50% immunity would lower it to 1.5, making it roughly as infectious as the flu in the population and only slightly more lethal.
