5 ms·

>The Bay area currently has 204 confirmed cases (as of 3/15). Multiplying that by either 10x or 50x (Harvard's estimated ratio of confirmed:unconfirmed cases) t

>The Bay area currently has 204 confirmed cases (as of 3/15). Multiplying that by either 10x or 50x (Harvard's estimated ratio of confirmed:unconfirmed cases) to get the actual number of confirmed cases today: 2,040 - 10,200 actual current cases in the Bay area. >... >80% of those will be "mild" which means "possibly as bad as having pneumonia but not needing a hostpital stay." 14% will require a hospital bed. I have an issue with extrapolating the number of serious cases this way. I assume the 80% figure for non-serious cases is based on the number of formally tested patients. Therefore the 80% figure doesn't include all the community-spread undiagnosed cases that must also be non-serious (or they would have been in hospital). The percentage of serious cases amongst the true number of cases is presumably much smaller than 20%?

rrss 7y ago
The 80% figure comes from a study of 72k cases in Hubei. It may have the problem you suggest, but China was/is testing much more aggressively than the United States. http://weekly.chinacdc.cn/en/article/id/e53946e2-c6c4-41e9-9a9b-fea8db1a8f51 http://weekly.chinacdc.cn/en/article/id/e53946e2-c6c4-41e9-9...
asdfasgasdgasdg 7y ago
There is also the issue of assuming that social distancing only reduces the number of cases by 90%. Social distancing affects the exponent. Depending on how aggressive it is it could reduce the height of the peak by a lot more than 90%. I also have no idea the basis for the 10-50x assumption r.e. confirmed/unconfirmed cases.
- nwallin 7y ago
  No, social distancing affects the base, not the exponent.
YZF 7y ago
It's the nature of all these figures that you can calculate them relatively easily for known cases but are somewhat more illusive for all infections. That said I think you can put an upper bound on the number of undiagnosed cases out there by looking at deaths and hospitalizations (in places where that data is reasonably accurate). There's at least a few ways of getting ballpark figures: - https://cmmid.github.io/topics/covid19/severity/diamond_cruise_cfr_estimates.html https://cmmid.github.io/topics/covid19/severity/diamond_crui... (EDIT: this gives some estimates by age correcting the data from the diamond princess cruise which I think is one of the best data sets we have since most passengers got quarantined/tested/monitored). - looking at data from countries with reasonably strong testing regimes and responses. E.g. Israel or Canada are two I'm following. In Canada 12% of the cases so far required hospitalization (EDIT: https://torontosun.com/news/provincial/ontario-sees-spike-of-39-new-cases-of-coronavirus https://torontosun.com/news/provincial/ontario-sees-spike-of... ) - Surveillance test data for countries that do that. 20% does sound on the high side from what I've seen read. My mental ballpark is 5%-10%. I'm sure there are local variations (smokers, air pollution, age distribution, general health...) EDIT: The US has 62 reported deaths. Just estimating based on 0.5% ifr that gives 12,400 cases. Then you have to back-adjust this. Let's say by 2 weeks? That's maybe on the order of 100k+. Obviously this will have a very large error bar but it gives us some intuition. Feel free to poke holes at my math ;)

rrss 7y ago

The 80% figure comes from a study of 72k cases in Hubei. It may have the problem you suggest, but China was/is testing much more aggressively than the United States. http://weekly.chinacdc.cn/en/article/id/e53946e2-c6c4-41e9-9a9b-fea8db1a8f51 http://weekly.chinacdc.cn/en/article/id/e53946e2-c6c4-41e9-9...

asdfasgasdgasdg 7y ago

There is also the issue of assuming that social distancing only reduces the number of cases by 90%. Social distancing affects the exponent. Depending on how aggressive it is it could reduce the height of the peak by a lot more than 90%. I also have no idea the basis for the 10-50x assumption r.e. confirmed/unconfirmed cases.

nwallin 7y ago
No, social distancing affects the base, not the exponent.

YZF 7y ago

It's the nature of all these figures that you can calculate them relatively easily for known cases but are somewhat more illusive for all infections. That said I think you can put an upper bound on the number of undiagnosed cases out there by looking at deaths and hospitalizations (in places where that data is reasonably accurate). There's at least a few ways of getting ballpark figures: - https://cmmid.github.io/topics/covid19/severity/diamond_cruise_cfr_estimates.html https://cmmid.github.io/topics/covid19/severity/diamond_crui... (EDIT: this gives some estimates by age correcting the data from the diamond princess cruise which I think is one of the best data sets we have since most passengers got quarantined/tested/monitored). - looking at data from countries with reasonably strong testing regimes and responses. E.g. Israel or Canada are two I'm following. In Canada 12% of the cases so far required hospitalization (EDIT: https://torontosun.com/news/provincial/ontario-sees-spike-of-39-new-cases-of-coronavirus https://torontosun.com/news/provincial/ontario-sees-spike-of... ) - Surveillance test data for countries that do that. 20% does sound on the high side from what I've seen read. My mental ballpark is 5%-10%. I'm sure there are local variations (smokers, air pollution, age distribution, general health...) EDIT: The US has 62 reported deaths. Just estimating based on 0.5% ifr that gives 12,400 cases. Then you have to back-adjust this. Let's say by 2 weeks? That's maybe on the order of 100k+. Obviously this will have a very large error bar but it gives us some intuition. Feel free to poke holes at my math ;)