Results from community testing in Iceland - Printable Version
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Results from community testing in Iceland - BostonCard - 04-14-2020
https://www.nejm.org/doi/full/10.1056/NEJMoa2006100?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
RE: Results from community testing in Iceland - 2006alum - 04-14-2020
BC, is it a reasonable read to think this suggests the IFR might be lower than we feared but that the undetected community spread is also probably a lot lower too? If so, could one infer from the latter that we probably don't have quite as many undetected, asymptomatic cases as perhaps the Columbia pregnancy study might suggest if we extrapolated it out nationwide?
It's so striking to me how much the CFR seems to vary depending on public health infrastructures - my guess is that Iceland had such a low mortality rate because they intervened so early and probably got to the sicker patients before it was end stages. In that sense, the U.S. response of "don't go to the ER until you're practically suffocating" seems likely to be harmful from a CFR perspective?
RE: Results from community testing in Iceland - CardinalSagehen - 04-14-2020
(04-14-2020, 04:28 PM)BostonCard Wrote: https://www.nejm.org/doi/full/10.1056/NEJMoa2006100?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.
RE: Results from community testing in Iceland - BostonCard - 04-14-2020
(04-14-2020, 05:07 PM)CardinalSagehen Wrote: Iceland: 13.3% attack rate, 0.2% IFR.
While I agree with your broad point, the attack rate you quote is based on a selected sample; patients with symptoms and travel to high risk areas or contacts of infected patients. The overall attack rate is maybe 4000 (1221 who were diagnosed based on symptoms plus somewhere between 2-3000 undetected cases based on the random samples)/364,000 or about 1.1%.
That unfortunately is not enough herd immunity to make much of a difference.
One other datapoint, the town of Vó, Italy, where all 3000 residents were tested and 95 tested positive (attack rate of 3%). It had 1 death, so an IFR of about 1%, but very small sample size.
https://www.theguardian.com/commentisfree/2020/mar/20/eradicated-coronavirus-mass-testing-covid-19-italy-vo#maincontent
BC
RE: Results from community testing in Iceland - dabigv13 - 04-14-2020
Iceland has pretty favorable demographics. Their obesity rate is 23.9, life expectancy 83 years compared to the US, with obesity rate of 42%, life expectancy 78.7 years.
If you take these numbers, and take the 0.7% fatality rate on the cruise ship, and somewhere between those two is probably where we'll end up as long as we don't overwhelm health systems like in NYC or Lombardy, in which case that fatality rate probably increases a lot.
RE: Results from community testing in Iceland - BostonCard - 04-14-2020
Iceland's population is a little bit older than the US.
BC
RE: Results from community testing in Iceland - CardinalSagehen - 04-14-2020
(04-14-2020, 05:50 PM)BostonCard Wrote:(04-14-2020, 05:07 PM)CardinalSagehen Wrote: Iceland: 13.3% attack rate, 0.2% IFR.
While I agree with your broad point, the attack rate you quote is based on a selected sample; patients with symptoms and travel to high risk areas or contacts of infected patients. The overall attack rate is maybe 4000 (1221 who were diagnosed based on symptoms plus somewhere between 2-3000 undetected cases based on the random samples)/364,000 or about 1.1%.
That unfortunately is not enough herd immunity to make much of a difference.
One other datapoint, the town of Vó, Italy, where all 3000 residents were tested and 95 tested positive (attack rate of 3%). It had 1 death, so an IFR of about 1%, but very small sample size.
https://www.theguardian.com/commentisfree/2020/mar/20/eradicated-coronavirus-mass-testing-covid-19-italy-vo#maincontent
BC
Yes, thank you for clarifying and reminding me of that. In addition, the other samples (cruise ship, Navy vessel, Gangelt) were in known hot-spots - not representative of most places right now. But still encouraging...
Update: Confirmed the Gangelt sample was random. They literally sampled 1/24th of the people in a town of 12,000.
https://spectator.us/covid-antibody-test-german-town-shows-15-percent-infection-rate/
While I don't know the details of Gangelt, I don't think it's all that much of a stretch to think that Manhattan might be as "hot" of a hot-spot as Gangelt.
Perhaps this also foreshadows what the Stanford antibody study will show.
RE: Results from community testing in Iceland - burger - 04-14-2020
Here's another data point, and a strange one: 397 homeless people staying at one shelter in Boston tested, 146 (36%) positive, all positives asymptomatic. I don't even know what to make of that. My first thought was systematic testing error.
https://www.wbur.org/commonhealth/2020/04/14/coronavirus-boston-homeless-testing
RE: Results from community testing in Iceland - needle - 04-14-2020
(04-14-2020, 09:35 PM)burger Wrote: Here's another data point, and a strange one: 397 homeless people staying at one shelter in Boston tested, 146 (36%) positive, all positives asymptomatic. I don't even know what to make of that. My first thought was systematic testing error.
https://www.wbur.org/commonhealth/2020/04/14/coronavirus-boston-homeless-testing
Maybe strange; not unique:
Quote: Over the weekend, a man incarcerated at Cummins Unit prison, an Arkansas state prison in Grady, tested positive for COVID-19, becoming the first prisoner in the state correctional system there to do so. The corrections department responded by quickly testing all the other men housed in the same barracks—mass testing that most other states have not done in their prisons.
The results, made public on Monday, were shocking: The state corrections department announced that a whopping 43 of the 46 other men in the housing unit had tested positive. They were all asymptomatic and are now quarantined.
https://www.motherjones.com/coronavirus-updates/2020/04/cummins-unit-prison-arkansas-coronavirus-spread/
RE: Results from community testing in Iceland - burger - 04-15-2020
(04-14-2020, 09:35 PM)burger Wrote: Here's another data point, and a strange one: 397 homeless people staying at one shelter in Boston tested, 146 (36%) positive, all positives asymptomatic. I don't even know what to make of that. My first thought was systematic testing error.
https://www.wbur.org/commonhealth/2020/04/14/coronavirus-boston-homeless-testing
Looks like the NPR article was off a bit. A few people had symptoms: https://www.medrxiv.org/content/10.1101/2020.04.12.20059618v1
Quote:Cough (7.5%), shortness of breath (1.4%), and fever (0.7%) were all uncommon among COVID-positive individuals.
The article didn't break down the number of infected people with any symptoms, but the possible range is 7.5% to 16%. That's well within the range of some of the other studies lately implying a low IFR.
We have multiple data sources now all pointing to a low IFR and a high number of asymptomatic/mild cases. Interesting (and good).
RE: Results from community testing in Iceland - Goose - 04-15-2020
(04-15-2020, 10:14 AM)burger Wrote: We have multiple data sources now all pointing to a low IFR and a high number of asymptomatic/mild cases. Interesting (and good).Low IFR is good. A high number of asymptomatic cases is not so good. These people will spread the disease without knowing they are sick. COVID-19 was hard to deal with because it could be spread by presymptomatic people. If there are an even larger number of asymptomatic spreaders, it will be even more difficult to contain.
RE: Results from community testing in Iceland - Goose - 05-21-2020
It is interesting to examine https://www.icelandreview.com/ask-ir/whats-the-status-of-covid-19-in-iceland/
Since it is relatively easy to control access to the country, Iceland has a lot of advantages in this outbreak. That said, their number of cases per day has behaved exactly as we were told it should, in theory. Note that their residual infection rate is essentially zero. It is also true that they never came anywhere close to testing the entire population. They almost assuredly never will either, because it is no longer interesting. They are all negative. According to https://icelandmonitor.mbl.is/news/news/2020/05/21/one_new_case_of_covid_19_in_iceland/
15.7 percent of the nation has been tested to date. It is also telling that over time 57% of the positive cases were from people already quarantined. That explains a lot of their success.