I am an EA living in China right now. Thanks for sharing this post on the Coronavirus. I am also very interested in these questions.
We do not know what percentage of people experience symptoms so mild that they do not seek medical attention and so do not appear in the ‘Suspected’ or ‘Confirmed’ case statistics.
Nevertheless, as you mentioned, attempts have been made to model the spread of the infection and to estimate the number of people carrying the virus so far.
I have created a very simple spreadsheet with three scenarios here:
The Red scenario = 50% of infections go undiagnosed (unrecorded).
The Yellow scenario = 70% of infections go undiagnosed (unrecorded).
The Green scenario = 85% of infections go undiagnosed (unrecorded).
Each scenario has different estimates of the ‘real’ number of infections and percentages that progress to either a serious/critical condition or to death.
We can perhaps use these scenarios to roughly ‘frame’ whether this virus is similar or much worse than the seasonal flu. Thoughts?
There are potential inaccuracies with the numbers in the three scenarios.
On the potential positive (good) side, perhaps the high critical condition and death rates reflect the early stages of treating a novel virus and it’s possible that the rate will not be so high in future as better treatment protocols are followed. Certainly the rates seem much worse in Hubei Province compared to the rest of China and the rest of the world.
On the negative (bad) side, the death rate and serious/critical condition rate may turn out to be higher than the number reflected here. This is because many of the ‘suspected and confirmed’ cases will later progress to a serious/critical condition or death. There is likely to be a time lag in this progression which we do not yet see in the stats.
Moreover, perhaps the virus could become more deadly if medical services were to become overwhelmed.
Perhaps the questions could be summarised:
What percentage of cases go unrecorded (undiagnosed)? What is the real number of people with infections right now?
Which scenario: Green, Yellow or Red is closest to the truth? What confidence would you assign to the probability of each of the three scenarios?
What is the ‘true’ risk of progressing to a serious/critical condition or death once infected with Coronavirus?
I would love to hear any thoughts from others on any of the points made here.
-The spreadsheet compares the current number of deaths with the current number of known cases. However, deaths will always leak behind the number of confirmed cases; this way you will be underestimating death rate.
-It might also be interesting to do some back of the envelope math on the cases outside of China, since discovery rate should be much higher. So far, there are very few serious, and I think no critical conditions. However, most confirmed infections outside of China are actually people who were infected in China and then traveled overseas which selects for people healthy enough to travel, so mostly younger. Doing a proper analysis of those numbers will be hard; one could compare them to SARS figures of the relevant age bracket.
I am an EA living in China right now. Thanks for sharing this post on the Coronavirus. I am also very interested in these questions.
We do not know what percentage of people experience symptoms so mild that they do not seek medical attention and so do not appear in the ‘Suspected’ or ‘Confirmed’ case statistics.
here: https://ncov.dxy.cn/ncovh5/view/pneumonia
and here: https://www.worldometers.info/coronavirus/
Here’s Google Translate if you need it: https://translate.google.com/
Nevertheless, as you mentioned, attempts have been made to model the spread of the infection and to estimate the number of people carrying the virus so far.
I have created a very simple spreadsheet with three scenarios here:
https://docs.google.com/spreadsheets/d/1qSNLQC5BpA-Gah0INyolFpPvTAGFphKUwTxQZN7FWI4/edit?usp=sharing
The Red scenario = 50% of infections go undiagnosed (unrecorded).
The Yellow scenario = 70% of infections go undiagnosed (unrecorded).
The Green scenario = 85% of infections go undiagnosed (unrecorded).
Each scenario has different estimates of the ‘real’ number of infections and percentages that progress to either a serious/critical condition or to death.
I found the serious/critical condition numbers here: https://twitter.com/BNODesk
We can perhaps use these scenarios to roughly ‘frame’ whether this virus is similar or much worse than the seasonal flu. Thoughts?
There are potential inaccuracies with the numbers in the three scenarios.
On the potential positive (good) side, perhaps the high critical condition and death rates reflect the early stages of treating a novel virus and it’s possible that the rate will not be so high in future as better treatment protocols are followed. Certainly the rates seem much worse in Hubei Province compared to the rest of China and the rest of the world.
On the negative (bad) side, the death rate and serious/critical condition rate may turn out to be higher than the number reflected here. This is because many of the ‘suspected and confirmed’ cases will later progress to a serious/critical condition or death. There is likely to be a time lag in this progression which we do not yet see in the stats.
Moreover, perhaps the virus could become more deadly if medical services were to become overwhelmed.
Perhaps the questions could be summarised:
What percentage of cases go unrecorded (undiagnosed)? What is the real number of people with infections right now?
Which scenario: Green, Yellow or Red is closest to the truth? What confidence would you assign to the probability of each of the three scenarios?
What is the ‘true’ risk of progressing to a serious/critical condition or death once infected with Coronavirus?
I would love to hear any thoughts from others on any of the points made here.
Just some quick thoughts:
-Your lowest discovery rate (15%) might still be too high, this recent preprint estimates 0.05% https://www.medrxiv.org/content/10.1101/2020.01.23.20018549v2.full.pdf
-The spreadsheet compares the current number of deaths with the current number of known cases. However, deaths will always leak behind the number of confirmed cases; this way you will be underestimating death rate.
-It might also be interesting to do some back of the envelope math on the cases outside of China, since discovery rate should be much higher. So far, there are very few serious, and I think no critical conditions. However, most confirmed infections outside of China are actually people who were infected in China and then traveled overseas which selects for people healthy enough to travel, so mostly younger. Doing a proper analysis of those numbers will be hard; one could compare them to SARS figures of the relevant age bracket.
Sorry, the link to the ‘live’ statistics from Chinese Health centres was broken:
https://ncov.dxy.cn/ncovh5/view/pneumonia
I’ve also updated the link in the original post.
Here’s Google Translate if you need it: https://translate.google.com/