My impression is that the WHO has been dividing up confirmed cases into mild/moderate (≈80%) and severe/critical (20%). The guesstimate model assumes that there are 80% “mild” cases, and 20% “confirmed” cases, which is inconsistent with WHO’s terminology. If you got the 80%-number from WHO or some other source using similar terminology, I’d recommend changing it. If you got it from a source explicitly talking about asymptomatic cases or so-mild-that-you-don’t-go-to-the-doctor, then it seems fine to keep it (but maybe change the name).
Edit: Wikipedia says that Diamond Princess had 392⁄705 asymptomatic cases by 26th February. Given that some of the patients might go on to develop symptoms later on, ≈55% might be an upper bound of asymptomatic cases?
Most people infected with COVID-19 virus have mild disease and recover. Approximately 80% of laboratory confirmed patients have had mild to moderate disease, which includes non-pneumonia and pneumonia cases, 13.8% have severe disease (...) and 6.1% are critical (...). Asymptomatic infection has been reported, but the majority of the relatively rare cases who are asymptomatic on the date of identification/report went on to develop disease. The proportion of truly asymptomatic infections is unclear but appears to be relatively rare and does not appear to be a major driver of transmission.
My impression is that the WHO has been dividing up confirmed cases into mild/moderate (≈80%) and severe/critical (20%). The guesstimate model assumes that there are 80% “mild” cases, and 20% “confirmed” cases, which is inconsistent with WHO’s terminology. If you got the 80%-number from WHO or some other source using similar terminology, I’d recommend changing it. If you got it from a source explicitly talking about asymptomatic cases or so-mild-that-you-don’t-go-to-the-doctor, then it seems fine to keep it (but maybe change the name).
Edit: Wikipedia says that Diamond Princess had 392⁄705 asymptomatic cases by 26th February. Given that some of the patients might go on to develop symptoms later on, ≈55% might be an upper bound of asymptomatic cases?
Some relevant quotes from WHO-report (mostly to back up my claims about terminology; Howie questions the validity of the last sentences further down in this thread):