I think the estimates in your links are not central estimates, even conditioning on 10% of the world being infected. The analysis in the Medium article basically assumes the worst case on every axis. So yeah, that will look pretty bad. And I think it is a good way to get a picture of what the right tail on this looks like. But it’s pretty far from the most likely outcome. Mitigating factors that are ignored:
Related to the above, we’re starting to get a sense of how it spreads, which should help us to slow the spread
Fatality rates so far may be much smaller than these worst case estimates, if the number of mild cases that were not detected is large. This is more likely to be true in Wuhan, where capacity for testing may have been stressed as well as capacity for treating. It is also more likely in the worlds where where ~50% of people become infected
Most published estimates of R0 are closer to the smaller end of the scale reported in that Medium article (2-2.5 from the WHO, 2-3 from JAMA, vs 1.4-3.8), and for comparison to influenza, 1.28 is on the smaller end of flu outbreak R0 estimates (~1.5 for the 2009 outbreak, and why did he use a point value with three significant figures for such an imprecisely measured thing?)
Any measure to slow down the virus will spread out the stress to hospitals. It’s not as if we’ll wake up one morning and half of all people in our town will be infected. We should be less concerned about how many people will be infected and more concerned about how many people will be infected at once.
Warmer weather usually makes these things less bad, which may slow the spread over the coming months
If it looks like I’m reaching for arguments for not being worried, that’s because I kind of am (though I do think everything I said here is true). But that’s how the Medium article reads to me. It is very unlikely that all of the bad things will happen and none of the good things will happen.
It seems like your arguments can be summed up as “if we slow the spread enough, hospitals won’t be overwhelmed” but the US only has 924,107 beds in total, and if each case takes 4 weeks to recover (“People with more severe cases generally recover in three to six weeks.”) we can treat 11 million people or 3.4% of the population over a year, but that would mean death rates from other diseases would rise a lot since those patients wouldn’t have beds. Many countries do have a lot more beds per capita than the US (which surprises and confuses me) but presumably they’re almost all being used already?
ETA: Actually the limiting factor probably isn’t hospital beds but equipment for treating respiratory disease. For example according to this paper:
The median number of full-feature mechanical ventilators per 100,000 population for individual states is 19.7 (interquartile ratio 17.2-23.1)
This works out to be about 65,000 in the whole country which is a small fraction of what’s needed to treat the number of people who will need them (.05 * .5 * 327e6 = 8,175,000) even spread out over a year or two.
I’m also arguing that we might just have many fewer severe cases than these right-tail estimates are indicating. So far, Hubei has only had .1% of their population get confirmed cases, for example, and I think that many scenarios in which >10% of people are infected globally are ones in which the actual number of cases in Hubei is much larger than .1%.
I also think there are more reasons for expecting fewer severe cases in many parts of the world than in China, like the increased prevalence of smoking in China, relative to places like the US.
in which the actual number of cases in Hubei is much larger than .1%.
I think Wei Dai’s position is compatible with there being 10x as many undiagnosed cases in Hubei as diagnosed ones. But maybe you’re suggesting that it could be more like 50x?
10x currently seems like the right ballpark to me.
Those predictions are based on 80% of cases being mild. My claim is that if 90% of cases are undiagnosed, then substantially less than 20% will be severe.
I think the estimates in your links are not central estimates, even conditioning on 10% of the world being infected. The analysis in the Medium article basically assumes the worst case on every axis. So yeah, that will look pretty bad. And I think it is a good way to get a picture of what the right tail on this looks like. But it’s pretty far from the most likely outcome. Mitigating factors that are ignored:
China got a lot better at managing the epidemic over time, and everyone can learn from that. (See the WHO report linked in the reddit post: https://www.who.int/docs/default-source/coronaviruse/who-china-joint-mission-on-covid-19-final-report.pdf)
Related to the above, we’re starting to get a sense of how it spreads, which should help us to slow the spread
Fatality rates so far may be much smaller than these worst case estimates, if the number of mild cases that were not detected is large. This is more likely to be true in Wuhan, where capacity for testing may have been stressed as well as capacity for treating. It is also more likely in the worlds where where ~50% of people become infected
Most published estimates of R0 are closer to the smaller end of the scale reported in that Medium article (2-2.5 from the WHO, 2-3 from JAMA, vs 1.4-3.8), and for comparison to influenza, 1.28 is on the smaller end of flu outbreak R0 estimates (~1.5 for the 2009 outbreak, and why did he use a point value with three significant figures for such an imprecisely measured thing?)
Any measure to slow down the virus will spread out the stress to hospitals. It’s not as if we’ll wake up one morning and half of all people in our town will be infected. We should be less concerned about how many people will be infected and more concerned about how many people will be infected at once.
Warmer weather usually makes these things less bad, which may slow the spread over the coming months
There is some evidence that east Asian populations are more susceptible (https://jamanetwork.com/journals/jama/fullarticle/2762510)
If it looks like I’m reaching for arguments for not being worried, that’s because I kind of am (though I do think everything I said here is true). But that’s how the Medium article reads to me. It is very unlikely that all of the bad things will happen and none of the good things will happen.
It seems like your arguments can be summed up as “if we slow the spread enough, hospitals won’t be overwhelmed” but the US only has 924,107 beds in total, and if each case takes 4 weeks to recover (“People with more severe cases generally recover in three to six weeks.”) we can treat 11 million people or 3.4% of the population over a year, but that would mean death rates from other diseases would rise a lot since those patients wouldn’t have beds. Many countries do have a lot more beds per capita than the US (which surprises and confuses me) but presumably they’re almost all being used already?
ETA: Actually the limiting factor probably isn’t hospital beds but equipment for treating respiratory disease. For example according to this paper:
This works out to be about 65,000 in the whole country which is a small fraction of what’s needed to treat the number of people who will need them (.05 * .5 * 327e6 = 8,175,000) even spread out over a year or two.
I’m also arguing that we might just have many fewer severe cases than these right-tail estimates are indicating. So far, Hubei has only had .1% of their population get confirmed cases, for example, and I think that many scenarios in which >10% of people are infected globally are ones in which the actual number of cases in Hubei is much larger than .1%.
I also think there are more reasons for expecting fewer severe cases in many parts of the world than in China, like the increased prevalence of smoking in China, relative to places like the US.
I think Wei Dai’s position is compatible with there being 10x as many undiagnosed cases in Hubei as diagnosed ones. But maybe you’re suggesting that it could be more like 50x?
10x currently seems like the right ballpark to me.
Those predictions are based on 80% of cases being mild. My claim is that if 90% of cases are undiagnosed, then substantially less than 20% will be severe.
Then you wouldn’t expect close contacts to both have severe disease frequently. I think this has occurred too frequently.