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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

#41

Post by guscost »

glofish wrote: post #39

Well, it looks like in the end that much-criticized imperial model might be right on transmission rates but way off on the fatality rate and with that predicted deaths. It pretty much looks like none of the epidemiological models are reasonably accurate on both, case numbers and fatally rates

If you're fitting a model to observations, they'll have something of an inverse (but of course non-linear) relationship. So if your virulence estimates are worse than your transmissivity estimates, or vice versa, the bad measurement is going to push the model out of whack.

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

#42

Post by SpicyLemonZest »

caiobegotti wrote: post #37
3fe9a03ccd14ca5 wrote: post #20

At what point have we scientifically reached "herd immunity"? Is it 50%, 90%, 99%?

https://en.wikipedia.org/wiki/Herd_immunity#Mechanics

Although it should be noted that incomplete herd immunity will still help, by reducing the number of other containment measures which must be taken.

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

#43

Post by nullc »

Spooks wrote: post #13
cm2187 wrote: post #2

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

I wonder if we did these preliminary tests with the flu if we would see a large death rate drop for influenza as well

The US's influenza mortality figures are a combined influenza and pneumonia figure because they usually don't even bother actually screening for influenza.

Research attempting to determine how much of that figure is infected with influenza have found figures like 1/3rd (though with large differences year to year).

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

#44

Post by istorical »

chrisseaton wrote: post #28
JamesBarney wrote: post #5

> The reason the tests were randomly taken from those at grocery and big-box stores is that these were people not isolating in their homes and presumably not at work and therefore not essential workers.

I don't understand - essential workers still going to work also have to eat, and so go to grocery shops like other people.

The sampling location isn't meant to exclude essential workers, it's meant to avoid only sampling essential workers.

IE: if you measured at workplaces that would capture only essential workers, if you measure at people's homes during work hours, you get people who mostly are quarantining, if you measure at a grocery, you might get a mix of both, etc.

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

#45

Post by jdm2212 »

brandmeyer wrote: post #33
jdm2212 wrote: post #25

Earlier quoted context omitted.

Roughly 1/1000 New Yorkers have died of coronavirus. At a 1% IFR, that suggests at least 10% of the state has gotten the virus. Probably more, because deaths are undercounted and many people who will die of the virus already have it but haven't died yet. In the Bay Area, almost no one has died of coronavirus so the infection rate should be next to nil.

I was astonished by your 1/1000 figure and had to look it up... If anything, its too low . 15k deaths (proven+probable) in 8M people is almost 2/1000. https://www1.nyc.gov/site/doh/covid/covid-19-data.page

I was referring to the state -- but, yeah, it's even worse in the city :(

and 2/1000 people * 1% IFR => 20%

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

#46

Post by jaynetics »

3fe9a03ccd14ca5 wrote: post #20

At what point have we scientifically reached "herd immunity"? Is it 50%, 90%, 99%?

60-85%

1-1/R0

Most commonly the R0 of is assumed to be 2.5-3.0, but estimates range up to 6.5.

https://academic.oup.com/jtm/article/27/2/taaa021/5735319

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

#47

Post by TheBlight »

3fe9a03ccd14ca5 wrote: post #19
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%!)

What's interesting is if you look at the rest of NY numbers (-NYC,LI,Westchester). That has infection at 3.6%. Santa Clara was estimated to be 3% and LA county 4%. So it's in strong agreement with those areas.

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

#48

Post by dwaltrip »

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…

I agree with everything you are saying. This does look like good news.

However, we should remember that this is probably a mild overestimate, as the study population was assembled from those who were out and about (shopping at the grocery store, etc). People who are more strictly staying home -- and thus less likely to have been infected -- wouldn't be included in the survey.

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

#49

Post by istorical »

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…

More contagious OR began community spread and became endemic much earlier.

r0 is part of the formula for total infected at X/Y/Z date but so is date of initial infection and size of initial infected population.

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

#50

Post by nullc »

grey-area wrote: post #40
3fe9a03ccd14ca5 wrote: post #20

At what point have we scientifically reached "herd immunity"? Is it 50%, 90%, 99%?

More like 50-80%, you just need spread to be impeded so that r falls below 1, but for that many people to get it would mean very high deaths, in the US 1% of 80% of 320m is > 2m deaths.

Keep in mind that if 21% of NYC residence have been infected this probably implies R0 in that population was higher than in most prior estimates of R0, which increases the threshold of immune people before R0 falls below 1.
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