and how many unconfirmed cases? I personally know 10 people who have had symptoms that are likely covid, but not serious enough to go get tested. The fact that the least symptomatic patients are also least likely to get tested means that the calculation you presented gives us, at best, an upper bound. A better way to get the true measure would be based on population-based antibody testing.

More info available at the WHO website: https://www.who.int/news-room/commentaries/detail/estimating...