Wildly different case fatality rates might be caused by the same infection fatality rate if milder infections are systematically less likely to turn into medica

Wildly different case fatality rates might be caused by the same infection fatality rate if milder infections are systematically less likely to turn into medical cases in some countries. Compare the age distribution of infections in Iceland versus the Netherlands for instance. https://twitter.com/alexandreafonso/status/1243557013759700997 https://twitter.com/alexandreafonso/status/12435570137597009... We have every reason to think that just as large a fraction of the 10-19 year olds in the Netherlands have gotten this in the Netherlands as in Iceland but when it stays as a cough and light fever many medical regimes are never going to test those cases. And countries have different demographic profiles, though not enough to explain a 10x difference. And medical systems get overwhelmed in some places which could possibly be up to a 10x difference in a really cases.