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Back of the envelope check as an exercise. Population of northern Italy. Assume everyone contacted covid. How many dead / pop More or less than 0.26% Or new
by harry8 6y ago
Back of the envelope check as an exercise.
Population of northern Italy. Assume everyone contacted covid.
How many dead / pop
More or less than 0.26%
Or new York, or London.
See what numbers you come up with. Is this a reasonable thing for the cdc to say or not?
Please do the exercise yourself and draw your own conclusion.
- mikem170 6y agoI wondered about that. But it is a reasonable number if you take into account that there were not enough tests to detect all cases. I assume that now they are getting antibody data and see that a lot more people caught this than they thought, not exhibiting symptoms or needing medical care. And there are things we still don't know, about how it spreads (turns out not so much on surfaces), and about variants that are out there (why worse in NYC and Europe than in parts of asia and west coast?) And local conditions (NYC is very dense with subways, Northern Italy with intergenerational housing and smoking, etc). More data is always good.
- harry8 6y ago> But it is a reasonable number if you take into account that there were not enough tests to detect all cases. Assume every single person contracted it and testing is irrelevant in the calculation. Then you can adjust down to 90% contracted covid, or 80% or 20% or whatever to see how that affects things if you want to. Start with deaths/population and see what number comes up. It's a really useful starting point. And a really useful skill to have to be able to check a supplied number with a back of the envelope calculation. I say do it! For more than one reason it's worthwhile.
- gnusty_gnurc 6y agoIFR is a linear combination of age groups and their associated risk. It turns out NYC was an unmitigated disaster around nursing homes. That'll drive up the statistics quite a bit in that dead/population figure you're mentioning.
- TheCoelacanth 6y agoNYC has a median age of two years younger than the country as a whole. Age distribution is not a plausible explanation for NYC having a particularly large number of deaths from the outbreak.
- zaroth 6y agoIt sounds like you are assuming the virus spreads uniformly through the population. It does not. The median age of the population isn’t as relevant as the prevalence of the virus within specific demographics in the population. NYC may have a slightly smaller elderly population, but that won’t matter if the prevalence of the virus in their elderly population is, say, 2x higher than the national average. I’ve only been following it loosely, but apparently NYC brought the virus into their nursing homes by discharging SARS-CoV-2 positive patients back into them, and the IFR in a nursing home is certainly not 0.2%.
- mindslight 6y agoThe original comment is putting a bound on the case fatality rate by simplistically assuming everyone has been infected. The actual prevalence in nursing homes is irrelevant with that assumption. Nursing homes being prone to infection just tightens the bound.
- zaroth 6y agoI think you are misreading OP. They are saying the prevalence in nursing homes was higher (“an unmitigated disaster”) which drives up the average IFR.
- mindslight 6y agoMy comment applied to the comment you're referencing as well. The original comment is the one above that.
- tinus_hn 6y agoA useless exercise unless you also take age distribution in account. Anyway for Lombardy, the hardest hit region of Italy the answer is 0.16%.