Data is from March 23rd, not today (numbers have changed):
Iceland is another interesting test case. If I read the story correctly, it sounds like they have their health system conducting screening of 4197 people (with something like a 10% positive rate, (473-48 = 425 positive out of 9768-5571 = 4197 health service tests)) in
symptomatic cases , and another 5571 tests conducted by deCode Genetics, with "random" population sampling. (It's very unclear how they achieved the population sampling, and that is critical to the conclusions.)
The "random" population sampling identified about 0.86% population prevalance of asymptomatic cases. (48/5571). I'm assuming all of those people were showing no symptoms otherwise they would have been tested by the health care system (article is unclear).
Iceland's population is 364k, so this would imply in the simplest interpretation that there are ~2700 = (0.86%-0.13%)*364k unidentified cases wandering around Iceland, while the actual identified symptomatic cases is just 425. So that would imply tons of unidentified community spread - so much so that the outbreak would be impossible to contain without complete population screening I would think. But I have my doubts about deCode's randomness. Maybe people submitting to random testing would be more likely to be international travelers, and have a higher disease prevalence? Or, even more important, would people who feel like they have a little bit of a scratchy throat or a sniffle but won't admit it be more likely to submit to "random" testing? It did appear to require effort on the part of the people submitting to testing - they have to take a trip to get their noses swabbed - so I can't see how that would end up being random. Anyway, I can't find data or a story on the sampling method.
COVID-19: First results of the voluntary screening on Iceland - Nordic Life Science – the leading Nordic life science news service
Anyway, something to keep an eye on as they continue to conduct random sampling. We'll see how that random sampling % tracks. I wouldn't be surprised to see it track down to 0.2% as they test more people - though of course as long as the outbreak continues it will always be increasing with time...though some people will just have antibodies and no virus. It's a tricky problem.