mars_or_bust
Member
This is very different because they have the luxury of testing everyone on the carrier. So there isn't really such a thing as an undiscovered case (to first order - there actually probably are due to false negatives).
Outside of these special cases, it's very likely true that there are 10x the cases in many more heavily hit areas than have been identified, simply due to undertesting.
It's true that the crazy talk about 50 - 100x more cases were always unbelievable, just based on other data from other countries and their outcomes. That sort of ratio never made sense, based on 1) the ability of South Korea to control the virus, and 2) their observed CFR. Those observations pointed to a ballpark IFR, which then could be used to estimate approximate case numbers. And they never looked like 50-100x. There are ways to calculate it from epidemiological projections and simulated outbreak sizes, too. Those also were not consistent with the 50-100x numbers. Lots of different ways to do it, all of them pointing to something more in the 10x-20x range at most.
I just learned from David Baltimore 5 minutes ago, when he mentioned that polio was quite similar in this respect - there were many children who were infected who were asymptomatic or mildly affected. It's apparently not that unusual for viruses.
OK, thanks for the info, clearer now.