Because it's possible that there are many, many infected who don't seroconvert or ever manifest symptoms, and therefore would not have been tested with a PCR test, and would have a negative antibody test. We can see this in effect in studies of household attack rates and seroconversion. See this recent preprint and interesting thread (/r/covid19 is a strict science sub, not to be confused with /r/coronavirus) https://www.reddit.com/r/COVID19/comments/hdxwf5/intrafamili...
arrrg|5 years ago
In Brooklyn and Queens between 0.2 and 0.25 percent of the total population (!) died.
So this sort of puts a floor on the IFR and 0.2 is not that far off from the IFR determined through serological testing – maybe a half or a third of that.
So yeah, maybe there is an effect – but can it really be a drastic effect? I don’t think there are orders of magnitude of difference in there, maybe a difference of a few percent (e.g. an IFR of 0.45 instead of 0.5 percent)?
My working hypothesis has been an IFR of around 0.5% for a pretty long time, which seems pretty realistic to me.
grey-area|5 years ago
If we have a higher immune population than we think, NYC might have passed the worst, if not millions will die in a second wave (though there are no signs of that yet). So this does matter.
jakeogh|5 years ago
un-nerfed link: https://old.reddit.com/r/COVID19/comments/hdxwf5/intrafamili...
jmull|5 years ago
Any potential people with covid19 but no symptoms would be above and beyond what’s being raised here.
gvjddbnvdrbv|5 years ago