It worries me that this study is relying on Chinese data.
Italy is doing a reasonable amount of testing and has more like 10% death rate. Could there be 15X more infected in Italy than detected? Or is it that they have mostly old people catching it? Seems like a large discrepancy either way.
If you look at Germany, South Korea you see a much lower death rate, but they also have younger populations. In this case you want the min, not the max or the average, because the death rate of the virus should be fixed. The lower the rate just tells you how effectively the country did their testing, and thus how accurate the denominator is.
What complicates that greatly is the fact that the age of the population matters a lot. And Italy has one of the oldest populations. Countries in Africa with very young populations would expect a much lower death rate - complicated again by their relatively poor population and health systems and incompetent and corrupt governments.
Given it's so close between Germany and Italy, testing probably accounts for the majority of the difference.
I think the CFR we see is mix of multiple things. Testing protocol (who gets testes - every possible case, only seriously sick etc), social structure (household structure, standard social behavior), demographics, chronic illnesses, health care capacity.
I have observed two patters. When there are low amount (~20%) of elderly among the infected and health care capacity is not reached then CFR can be very low <<1% (Germany 02.% in the beginning for long time, Norway 0.5%). When there the number of elderly reaches is > 50% then the CFR will be order of magnitude higher (Italy, Spain in the beginning).
When health care capacity is exceeded then CFR% will rise about 5 times (Italy, Spain).
Most of the people who got covid, are asymptomatic thus they probably won't be tested and added to the count.
This means that 10% is taken from a population of people who are both sick and symptomatic.
Since China is testing asymptomatic people as well, they should have a more precise ratio.
As a comparison, Germany has a <2% fatality rate and has tested more people than Italy.
Germany's good numbers may not hold.
20 days ago Germany had 7256 cases. Italy had 27977.
10 days ago Germany had 37307 cases. Italy had 74383.
0 days ago Germany had 96076 cases. Italy had 124629.
The point being that Germany saw the outbreak take hold considerably after Italy. Italy had a very low original death rate as well -- approximately 2% weeks into the outbreak. This virus takes weeks to kill most of its victims.
14 days ago Germany had a death rate of 0.375%.
7 days ago, Germany had a death to case rate of 0.75%.
Today it's at 1.5%. It has increased every day between.
The fact that Italy is a hyper-social society, while Germany, at least from my probably wrong foreign view, is quite the opposite, probably changed the path of the disease, accelerating its spread in Italy.
I assume that Western countries have some hope of containing this, but poor countries with large informal sectors?
I can't see it working out well, at all.
Another concern is covid stresses will extend to social instability, and not just in the poorer countries. . That's going to be really unpredictable.
Also beware that the Italian IFR for the bi-yearly flu peaks is extremely high, 1%. (2014 being much worse than this year with the new flu). The current IFR looks also to be in that ballpark.
A few countries are starting mid-sized randomized studies to look for antibodies in the general public and that will give us a much better idea of the scope.
To which it should be noted that already there is fake news spreading making broad claims that they already discovered XYZ (saw one atop Reddit).
I realize there are China sympathists on HN, however it is widely known and acknowledged that China has been very deceptive about the scale of the outbreak and the number of deaths.