For hospitalisation / intensive care, the original data from China had 14% “severe” and 5%”critical” cases. These are percentages of diagnosed cases so you would need to modify these with the diagnosis rate.
For the Diamond Princess about 50% of cases were asymptomatic so that is likely an upper limit on diagnosis rate. Ascertainment rates from these papers are highly variable so an actual number here is hard to estimate.
That suggests hospitalisation is probably no more than 10% and intensive care no more than 2.5%. These numbers are a bit lower than your model but not enough to get us out of the woods.
If most people who need it do not have access to ventilators, which is inevitable if even a percent of the population are infected at any one time, then it on the order of 4% of infected individuals will die.
I have heard ‘5-15%’ and ’20%′ and ‘12%’ for hospitalization/‘no-treatment fatality’ rates, with a trend that the newer estimates tend to be lower. The initial figure from China was a blood-curdling 20%, as you said, while a current projection based on evidence from real overwhelmed healthcare systems is a merely very bad 3-5%. This is lower by a larger factor than most of the reductions to the CFR that account for undocumented cases—perhaps indicating there are more undocumented cases than those corrections imply?
Also, of relevance to the UK’s strategy (cocooning older people from infection), how does this breakdown by age? This poster has estimated that young, male, no pre-existing condition have 1/4th the risk of hospitalization (assuming a 50⁄50 chance that the intersection of age-30/no-pre-existing condition has a much lower risk than either alone) - which means if older and vulnerable people can be ‘cocooned’, the actual rate of hospitalization can be slashed again by a factor of 4 to something bearable, around 1%, if you take 4% as the baseline.
(note that the corrections in this paper for delay to death and underreporting skew the death rates even more strongly towards older patients, with the fatality rate among 20-29 barely changing after adjustment but the fatality rates among 60+ doubling).
That means you could surf a wave of a few hundred thousand people having the virus at a time and still provide adequate ICU space. With some expansion in capacity, that could be even higher.
Nice model.
For hospitalisation / intensive care, the original data from China had 14% “severe” and 5%”critical” cases. These are percentages of diagnosed cases so you would need to modify these with the diagnosis rate.
For the Diamond Princess about 50% of cases were asymptomatic so that is likely an upper limit on diagnosis rate. Ascertainment rates from these papers are highly variable so an actual number here is hard to estimate.
That suggests hospitalisation is probably no more than 10% and intensive care no more than 2.5%. These numbers are a bit lower than your model but not enough to get us out of the woods.
From the blog post:
I have heard ‘5-15%’ and ’20%′ and ‘12%’ for hospitalization/‘no-treatment fatality’ rates, with a trend that the newer estimates tend to be lower. The initial figure from China was a blood-curdling 20%, as you said, while a current projection based on evidence from real overwhelmed healthcare systems is a merely very bad 3-5%. This is lower by a larger factor than most of the reductions to the CFR that account for undocumented cases—perhaps indicating there are more undocumented cases than those corrections imply?
Also, of relevance to the UK’s strategy (cocooning older people from infection), how does this breakdown by age? This poster has estimated that young, male, no pre-existing condition have 1/4th the risk of hospitalization (assuming a 50⁄50 chance that the intersection of age-30/no-pre-existing condition has a much lower risk than either alone) - which means if older and vulnerable people can be ‘cocooned’, the actual rate of hospitalization can be slashed again by a factor of 4 to something bearable, around 1%, if you take 4% as the baseline.
(note that the corrections in this paper for delay to death and underreporting skew the death rates even more strongly towards older patients, with the fatality rate among 20-29 barely changing after adjustment but the fatality rates among 60+ doubling).
That means you could surf a wave of a few hundred thousand people having the virus at a time and still provide adequate ICU space. With some expansion in capacity, that could be even higher.
Thanks for digging these up! I updated the model. Still terrible.