[CardinalSagehen]

https://www.nejm.org/doi/full/10.1056/NE...0?query=RP

The study looked at ~9000 people who were targetted screens (symptomatic patients with travel to high risk areas or contacts of infected people), of which 1221 were positive (13.3%).  They also sent out an open invitation, of which ~10,000 people volunteered to get tested, 87 of whom were positive (0.8%) and a random sample of 2283, of which 13 were positive (0.6%).  Extrapolating that to the entire population of Iceland (364,000), you get about 2000 to 3000 undetected patients, so that suggests about 2 - 3 undetected cases for each known case.

Iceland has had 8 deaths due to COVID-19 to date, so the infection fatality rate is about 0.2% (worse than influenza, but not quite as bad as feared).  You might expect a few more before all this is said and done, but I don't think the IFR will rise above 0.5%, which is indeed good news.

BC

Yes. 

Iceland: 13.3% attack rate, 0.2% IFR.

Gangelt, Germany: 14% attack rate, 0.37% IFR.  Sampled 500 people out of 12,000 in the town, using antibody testing.

USS Theodore Roosevelt: Of the ~4,845 crew members, 589 have tested positive. Attack rate ~12%, assuming everyone has been tested, which I don't know.

Diamond Princess:  "Among 3,711 Diamond Princess passengers and crew, 712 (19.2%) had positive test results for SARS-CoV-2."

To me (and many others), known case counts are completely meaningless, due to the inconsistency and unavailability of testing.  And due to humans that were afraid or didn't wish to be tested, even though they showed all the symptoms - especially young, single people, including two of my younger colleagues.  

The only numbers that seem to mean anything are attack rates from random samples using antibody testing, hospitalizations and (very sadly) deaths, which tend to follow infections by ~20 days. 

The good news from all of these studies is not just that the IFR is looking lower than originally feared, but also that the virality factor would be materially lower if ~14% of the population has already been infected and maintains some immunity.  That's not an immaterial number to slow down the ongoing rate of infection.

[CardinalSagehen]

https://www.nejm.org/doi/full/10.1056/NE...0?query=RP

The study looked at ~9000 people who were targetted screens (symptomatic patients with travel to high risk areas or contacts of infected people), of which 1221 were positive (13.3%).  They also sent out an open invitation, of which ~10,000 people volunteered to get tested, 87 of whom were positive (0.8%) and a random sample of 2283, of which 13 were positive (0.6%).  Extrapolating that to the entire population of Iceland (364,000), you get about 2000 to 3000 undetected patients, so that suggests about 2 - 3 undetected cases for each known case.

Iceland has had 8 deaths due to COVID-19 to date, so the infection fatality rate is about 0.2% (worse than influenza, but not quite as bad as feared).  You might expect a few more before all this is said and done, but I don't think the IFR will rise above 0.5%, which is indeed good news.

BC

Yes. 

Iceland: 13.3% attack rate, 0.2% IFR.

Gangelt, Germany: 14% attack rate, 0.37% IFR.  Sampled 500 people out of 12,000 in the town, using antibody testing.

USS Theodore Roosevelt: Of the ~4,845 crew members, 589 have tested positive. Attack rate ~12%, assuming everyone has been tested, which I don't know.

Diamond Princess:  "Among 3,711 Diamond Princess passengers and crew, 712 (19.2%) had positive test results for SARS-CoV-2."

To me (and many others), known case counts are completely meaningless, due to the inconsistency and unavailability of testing.  And due to humans that were afraid or didn't wish to be tested, even though they showed all the symptoms - especially young, single people, including two of my younger colleagues.  

The only numbers that seem to mean anything are attack rates from random samples using antibody testing, hospitalizations and (very sadly) deaths, which tend to follow infections by ~20 days. 

The good news from all of these studies is not just that the IFR is looking lower than originally feared, but also that the virality factor would be materially lower if ~14% of the population has already been infected and maintains some immunity.  That's not an immaterial number to slow down the ongoing rate of infection.