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Preliminary test results suggest 21% of NYC residents have Covid antibodies

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Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#11

Post by Exmoor »

cm2187 wrote: post #2

Another datapoint suggesting the death rate of this virus is within 0.5%.

Also another data point suggesting that the virus is much more contagious than the early estimates said.

I personally don't see how the test, track and trace efforts that have been touted as the only way to open things up can work with a virus with these characteristics. You would need to test a huge percentage of the population each day with quick results tests and something like that is many months away from being possible assuming it ever would be possible.

Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#12

Post by cm2187 »

CubsFan1060 wrote: post #10
cm2187 wrote: post #6

Earlier quoted context omitted.

I don't know what to make of that. I would expect people at work to have higher infection rate (not the least because many of these jobs involve contact with the population). It also filters out older and sick people. So intuitively I would expect to undershoot the actual rate.

I read it as people shopping, not people that work there. So folks who are out-and-about, but are not in the more likely to have it groups (healthcare workers or people working at the grocery store). You're right about older and sick people.

No that's what I meant. People shopping and therefore not at work. Therefore intuitively I would expect the population tested to be less contaminated than the population not tested (because at work).

Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#14

Post by guscost »

CubsFan1060 wrote: post #8
guscost wrote: post #7

While this is great information, a few facts will still confound attempts to speculate based on this number: - The production of IgG antibodies is mostly delayed until after an infection is cleared. - This is a random sample of people who were outside, it's not representative of the total population. - Non-trivial numbers of people may never develop detectable antibodies for SARS-CoV-2: https://www.medrxiv.org/conten…

If I follow, your first and third points would indicate the number may actually be higher? Additionally, does your third point also indicate that they will never be immune, or just that we won't be able to test for it?

All three could push the true total higher, but number two easily could push it lower instead. And I'm not a microbiologist but I think lack of antibodies only means that we won't be able to test for past infection. The seronegative patients (determined by a very precise method for measuring antibodies) in the second cited paper were still able to clear their infections.

Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#15

Post by tempsy »

guscost wrote: post #7

While this is great information, a few facts will still confound attempts to speculate based on this number: - The production of IgG antibodies is mostly delayed until after an infection is cleared. - This is a random sample of people who were outside, it's not representative of the total population. - Non-trivial numbers of people may never develop detectable antibodies for SARS-CoV-2: https://www.medrxiv.org/conten…

Also don’t know if people with antibodies can still spread the virus to others or whether antibody levels (not just presence) determines whether you can be reinfected.

Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#16

Post by cozzyd »

cm2187 wrote: post #2

Another datapoint suggesting the death rate of this virus is within 0.5%.

I had the opposite conclusion. There are between 10k-15k COVID-19 associated deaths in NYC, depending on how you count (the higher rate is consistent with the excess-mortality data, I believe). That by itself produces a range of ~0.56%-0.86% if you assume 21.2 % of NYC has been infected (larger range if you allow for some error on the infection rate, obviously). Moreover, we don't know what fraction of the currently-infected who will die have already died. A reasonable guess might be 50%, which would mean that the fatality rate for NYC is somewhere between 1.1 and 1.7%.

Either way, based on NYC, 0.5% might be a hard lower bound on the all-population fatality rate (of course, maybe NYC is not a representative sample for some reason)

Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#17

Post by ccleve »

This study doesn't appear to suffer from the same methodology problems as the Stanford study of a few days ago. In that study, they recruited people through Facebook, and reported an infection rate that was low enough that it could have been caused by false positives.

Here, it's closer to a random sample, but more importantly it shows really high rates. Those rates overwhelm any error due to false positives.

Also, it shows numbers that are in line with our intuition. It shows higher infections in NYC, and higher infections among blacks. That reflects what the hospitals are seeing.

This study may well be really good news.

Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#18

Post by daxfohl »

Exmoor wrote: post #11
cm2187 wrote: post #2

Another datapoint suggesting the death rate of this virus is within 0.5%.

Also another data point suggesting that the virus is much more contagious than the early estimates said. I personally don't see how the test, track and trace efforts that have been touted as the only way to open things up can work with a virus with these characteristics. You would need to test a huge percentage of the population each day with quick results tests and something like that is many months away from being…

I agree. But it seems to have worked in Korea. The math doesn't seem to reconcile somehow. Actually probably the prevalence of masks explains the difference.

Re: Preliminary test results suggest 21% of NYC residents have Covid antibodies

#19

Post by 3fe9a03ccd14ca5 »

ccleve wrote: post #17

This study doesn't appear to suffer from the same methodology problems as the Stanford study of a few days ago. In that study, they recruited people through Facebook, and reported an infection rate that was low enough that it could have been caused by false positives. Here, it's closer to a random sample, but more importantly it shows really high rates. Those rates overwhelm any error due to false positives. Also, it…

What's weird is that the Stanford study was suggested to have exaggerated the results, since those who suspected themselves as having the virus at one time were more likely to volunteer (allegedly). However, those results were nowhere near as big as this (I think like 2%-3% versus the 20%!)
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