France has 14.6% mortality (total cases divided by mortality, Worldometers). Italy, UK, Belgium, Sweden and Netherlands are over 10%. Spain is right at 10%. The US at 6%. Germany at 4.4%. South Korea 2.5%. Japan 4/10ths of a percent.
There are large numbers of cases in many countries, but mortality percentages differ greatly. Why? Tabulating criteria? Quality of medical care? Average age or underlying health conditions of patients? Population density? Environmental conditions (such as pollution). A combination of these and/or others?
One possibility: 3.6% of Japanese are obese (BMI over 30). The correlation doesn't hold well among western nations, however, where the rate is 39% of Americans, 29% UK and 23% Germany (figures limited to adults for these three nations).
These are the questions that need answering I think. I tend to think it is a combination of factors, but then which of those factors is most meaningful? For example CR mentions density:
Interestingly, Seoul's population density is almost twice that of New York City, four times higher than Los Angeles and eight times higher than the density of Rome.
Diet? Past experience with viral outbreaks? How about effectiveness of local govt? Life cycle of the virus?
Here is a study from Canada:
Canadian study finds temperature, latitude not associated with COVID-19 spread
A new study finds that temperature and latitude do not appear to be associated with the spread of coronavirus disease 2019 (COVID-19), but school closures and other public health measures are having a positive effect.
BTW, This is the 3rd source I have seen that mentions closing schools to have a positive effect.
The gold standard of mortality won’t be available for a year or two. At that time you will be able to determine a simple number. Using years and years of historical records you determine two numbers. How many people were expected to die in 2020 In a a world without Covid, against how many actually did. Subtract one from the other and you have “excess mortality”. That is how many were killed, by all causes, from Covid. All causes: Covid, suicide, delayed medical care, people that should have gone to a doctor but didn’t, ect
With all due respect, that number you cited-the 'excess mortality' number gleaned in the future won't directly address COVID deaths alone. As we are all finding out, deaths caused by suicide, depression, alcohol or drug abuse, physical abuse, delayed surgeries, etc. aren't directly attributable to COVID, but our response to COVID. It is entirely possible that our overzealous response may have put more people in harms' way than it has saved. We need to be able to suss this number from the COVID-specific deaths to have meaningful insight into how to deal with these things in the future. Assigning our self-wrought troubles (and ALL 'excess mortality') to COVID would be too simplistic.
Although, few are looking for the lives saved by lockdowns. I posted two separate studies a while back on lives saved due to pollution reduction and less traffic on the roads and fewer accidents. In CA alone fatal accidents were halved over the period measured. In the study on pollution in Europe an estimated 11,000+ lives were saved/extended during the month of study due to lower pollution rates, and other health conditions like asthma and early term births were lessened as well.
There are possibly more reasons people might be less vulnerable to certain causes of death in lockdown. Those should all be part of the count too.
So far worldwide suicides are tracking normally, as I posted in the same area.
Due to the connection between Covid and heart conditions that one is going to be hard to sort out in the end. Possibly also other underlying conditions where someone never was tested for Covid but died of another cause, yet had the virus.
It's all a big mess, but very complex.
They are all good points, with the last, that they are very complex being best. It is also very early.
You could argue that the lack of automobile accidents (and resultant savings in life) is partially offset by a reduction in the supply of organ transplants. Certainly suicide in two years from now from despair whatever the reason but linked to covid is certainly not counted.
Or the delay in scheduled operations causes many problems those surgeries would have found to be delayed. Conversely in the short run there will be less medical mistake deaths because those operations are delayed.
In the best of times, at least here in the US, you can't get reliable suicide numbers for two years and at least 1/3rd of all causes of death are incorrect.
We did however, have two very good petri dishes to look at early in this. The Diamnond Princess and the American warship.