I was analyzing some of the data surrounding COVID-19, and was looking at the vastly different mortality rates (calculated as
deaths / total cases * 100).
While there are probably many factors influencing differing mortality rates (age mainly), these variables are likely negligible compared to the main factor - number of tests issued. Countries that perform the most testing have revealed the lowest mortality rates in the world (Iceland at ~0.46% and Singapore at ~0.225, compared to Belgium at ~13.95%).
I calculated the mortality rate of New York City using the same method:
11477 Deaths / 123146 Cases * 100 = 9.32%
If we take Singapore's mortality rate as an example (assuming it's more accurate given the amount of testing), we can see that New York City's is 41.42 times higher:
9.32 / 0.225 = 41.42
If we apply the same to Iceland (which has tested massive amounts of their population, and in doing so discovered that many cases are completely asymptomatic), that makes NYC's rate 20.26 times higher.
If we then multiply these factors to the number of confirmed cases in NYC (123146), that gives us between 2,494,937 and 5,100,707 cases, or around 30-60% of the city's population!
While there's a lot more variables that need to be accounted for than in my over simplified analysis, if this is even somewhat true, couldn't that imply that these places that have been hit the hardest could be not far away from reaching a preliminary herd-immunity, and seeing a massive drop-off in infections and deaths?
Note: All data used here was the most recent as of 4/16/2020.