In places with aggressive testing, like Diamond Princess and South Korea, you see much lower fatality rates, which suggests that lots of cases are mild.
With South Korea, I think most cases have not had enough time to progress to fatality yet. With Diamond Princess, there are 7 deaths out of 707 detected cases so far, with more than half of the cases still active. I’m not sure how you concluded from this “that lots of cases are mild”. Please explain more? That page does say only 35 serious or critical cases, but I suspect this is probably because the passengers are now spread all over the world and updates on them (e.g. progressing to serious or critical) are no longer being provided (unless someone dies).
So plausibly there are 4x as many mild cases as severe cases. This gets us to like 3% fatality rate (again assuming no supplemental oxygen, which I don’t think is clear and I expect someone else to be able to make progress on forecasting if they want).
Also don’t understand this part. “4x as many mild cases as severe cases” is compatible with what I assumed (10%-20% of all cases end up severe or critical) but where does 3% come from?
Update on Diamond Princess: as of now, Wikipedia says that the death toll is 14, or 2% of the passengers who tested positive within the first month. However, the dead all seem to have been elderly (there were many elderly passengers, as expected for a cruise liner). More specifically, 11 of them were over 70, another was over 60, and two others were of undisclosed age due to family wishes.
I don’t know how to adjust those results for demographics, and of course you can’t use them to predict what would happen without hospital care. But it’s a promising sign (relative to Wei’d predictions) that we’ve made it this far without anything obviously worse than what happened in Italy and Spain, and even those have seen far less than 0.1% of their population die. NYC is estimated to have a 20% rate of infection, and it too has had less than 0.1% of its population die (though this may rise somewhat, as their wave of cases crested fairly recently).
I’ve now made a Guesstimate here. I suspect that it is very bad and dumb; please make your own that is better than mine. I’m probably not going to fix problems with mine. Some people like Daniel Filan are confused by what my model means; I am like 50-50 on whether my model is really dumb or just confusing to read.
Also don’t understand this part. “4x as many mild cases as severe cases” is compatible with what I assumed (10%-20% of all cases end up severe or critical) but where does 3% come from?
Yeah my text was wrong here; I meant that I think you get 4x as many unnoticed infections as confirmed infections, then 10-20% of confirmed cases end up severe or critical.
For what it’s worth I don’t see why the guesstimate makes sense—it assumes that the only people who die are those who get the disease during oxygen shortages, which seems wrong to me. [EDIT: it’s possible that I’m confused about what the model means, the way to check this would be to see if I believe something false about it and then correct my belief]
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.
With South Korea, I think most cases have not had enough time to progress to fatality yet. With Diamond Princess, there are 7 deaths out of 707 detected cases so far, with more than half of the cases still active. I’m not sure how you concluded from this “that lots of cases are mild”. Please explain more? That page does say only 35 serious or critical cases, but I suspect this is probably because the passengers are now spread all over the world and updates on them (e.g. progressing to serious or critical) are no longer being provided (unless someone dies).
Also don’t understand this part. “4x as many mild cases as severe cases” is compatible with what I assumed (10%-20% of all cases end up severe or critical) but where does 3% come from?
Update on Diamond Princess: as of now, Wikipedia says that the death toll is 14, or 2% of the passengers who tested positive within the first month. However, the dead all seem to have been elderly (there were many elderly passengers, as expected for a cruise liner). More specifically, 11 of them were over 70, another was over 60, and two others were of undisclosed age due to family wishes.
I don’t know how to adjust those results for demographics, and of course you can’t use them to predict what would happen without hospital care. But it’s a promising sign (relative to Wei’d predictions) that we’ve made it this far without anything obviously worse than what happened in Italy and Spain, and even those have seen far less than 0.1% of their population die. NYC is estimated to have a 20% rate of infection, and it too has had less than 0.1% of its population die (though this may rise somewhat, as their wave of cases crested fairly recently).
I’ve now made a Guesstimate here. I suspect that it is very bad and dumb; please make your own that is better than mine. I’m probably not going to fix problems with mine. Some people like Daniel Filan are confused by what my model means; I am like 50-50 on whether my model is really dumb or just confusing to read.
Yeah my text was wrong here; I meant that I think you get 4x as many unnoticed infections as confirmed infections, then 10-20% of confirmed cases end up severe or critical.
For what it’s worth I don’t see why the guesstimate makes sense—it assumes that the only people who die are those who get the disease during oxygen shortages, which seems wrong to me. [EDIT: it’s possible that I’m confused about what the model means, the way to check this would be to see if I believe something false about it and then correct my belief]
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):