Preliminary test results suggest 21% of NYC residents have Covid antibodies • Hacker News Board

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

#641

Post by usaar333 » Fri, Apr 24, 2020, 2:54 PM UTC

newacct583 wrote: post #527

usaar333 wrote: post #382

Earlier quoted context omitted.

Except this data is also lagging by three weeks, depending on what antibodies are being checked. Some deaths today have come from infections in April, so the net effect could be a wash. And where are you getting a 35% death rate for "ever hospitalized"? It's realistically somewhere around 15%-20%, though with major age skew. ( https://www.thelancet.com/journals/laninf/article/PIIS1473-3... )

Per https://covidtracking.com/data#state-ny there have been 57103 hospitalizations in the state (not city, so not quite the same population), of which 15021 are still hospitalized. So that's 42082 cases that have left the hospital, of which 15740 died, or 37%. Obviously there's some apples/oranges here, both due to the population being different from the city and the fact that some of those deaths were outside of hos…

Perhaps a lot of those deaths were outside hospitals (nursing homes, etc.)? Here's a report for all hospitalizations in NYC from March 1 to April 4: https://jamanetwork.com/journals/jama/fullarticle/2765184

21% of patients who discharged or died died.

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

#642

Post by newacct583 » Fri, Apr 24, 2020, 3:12 PM UTC

kalleboo wrote: post #595

newacct583 wrote: post #529

Earlier quoted context omitted.

This is like the third or fourth spot I've seen on this very site where people are postulating that covid deaths would have really died in "months" anyway. Why is this so weirdly consistent? To be clear: there is absolutely no evidence for a number like that, none at all. Typical at-risk patients with comorbidity like advanced age or obesity are routinely expected to live for decades. Actual conditions with a death-i…

Just some numbers: In Sweden, which only has a voluntary lockdown, over 30% of covid19 dead come from elderly homes[0]. Swedish elderly care is highly focused on keeping the elderly independent (at home) as long as possible, so the people in elderly homes are the ones in the worst state - 20% don't even survive one month from arrival[1] (I saw another statistic that 40% don't survive 6 months, but I can't find that s…

There are some bayesian tripwires in that analysis, though I think the data is good and it fits roughly with my intuition that bulk of covid deaths are in the "basically healthy and will live for many years" population.

The fact that a large-ish fraction of the entrants to the care homes die soon means that the people who don't die soon are going to be over-represented in the population. So if you pick a bunch of people from these homes at random, you probably (depending on the total population and total number of such deaths, which isn't cited) don't find people at the edge of death.

So I buy the upper bound, but think the actual number is likely to be much lower.

Stated more intuitively: there just aren't that many people "within months of death" at any time, and there are a lot of people dying to covid.

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

#643

Post by klmadfejno » Fri, Apr 24, 2020, 3:21 PM UTC

TheCowboy wrote: post #312

klmadfejno wrote: post #204

Earlier quoted context omitted.

I've been making many posts arguing against the efficacy of lockdowns (and been getting shat on by points I find mostly naive). I think something like this is probably the best approach because it minimizes economic harm while also trying to minimize hospitalization rates among the elderly. But even if we pretend we could implement a perfect bubble for everyone over 50, they're not especially safe when the lockdown i…

> I've been making many posts arguing against the efficacy of lockdowns (and been getting shat on by points I find mostly naive). I skimmed some of your comment history. Your comments aren't as rock solid as you believe, and there are many points either glossing over things or complete ignorance. > More people will die if the lockdown is lifted, and many of those who would have died anyway will die sooner. Are you re…

> Your comments aren't as rock solid as you believe, and there are many points either glossing over things or complete ignorance.

thanks man. I think you're demonstrating complete ignorance too. For instance, that quote of mine which you posted out of context clearly says the opposite of what you think it says. MORE people will die if the lockdown is lifted, and that those who would have died anyway (if it were not lifted) will die SOONER. Both obvious and uncontroversial.

That aside, triaging is very sad, but has a relatively small effect on total deaths, because the people you triage are the most likely to die, given care. This is very very different from random people dying who would not have died anyways. Hospitals that need to deny patients, which as far as I'm aware is just a single region in Italy with one of the oldest most vulnerable populations in the world, are doing so not because they can't actually take more people in for the most basic low level of care, but because there's basically nothing they can do.

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

#644

Post by koheripbal » Fri, Apr 24, 2020, 3:31 PM UTC

JackFr wrote: post #616

koheripbal wrote: post #546

Earlier quoted context omitted.

As a (40-something) NYC resident, I don't believe that is accurate. Half of the people I know are working from home and stocked up on 1-2 months of food at the outset of this. The other half left the city and are now staying with friends/family in other states or have rented homes elsewhere. Those that did stay and still need food (ie produce) are having it delivered. People who are shopping in stores are absolutely…

> Half of the people I know are working from home and stocked up on 1-2 months of food at the outset of this. Seriously? Your personal network is evidence the this study is useless because of sampling bias? Everyone I know voted for Hilary Clinton and yet here we are. > People who are shopping in stores are absolutely a very biased sample. People who have jobs that allow them to work from home are a very biased sampl…

> People who have jobs that allow them to work from home are a very biased sample.

Yes, exactly. ...just like the study's data that excludes them.

That's my point.

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

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Post by vannevar » Fri, Apr 24, 2020, 3:37 PM UTC

zaroth wrote: post #638

vannevar wrote: post #632

Earlier quoted context omitted.

"... it's not clear at all what our "drastic action" is achieving..." It's no coincidence that the city that shows a much higher prevalence also experienced a much more acute infection, straining their medical infrastructure. That isn't evidence that social distancing doesn't work, it's evidence that the infection was already well on its way before social distancing was implemented there. NYC was the canary in the co…

I actually agree with everything you said, but I still haven’t found the basis for the tremendously costly actions taken. As we can see, NYC did not particularly flatten their curve, and they did not see excess deaths due to lack of available care. They already hit the endpoint prevalence that you would see with the flu in a very bad year. It’s not clear how much further SARS-CoV-2 would go naturally — the S curve do…

NYC did not particularly flatten their curve, and they did not see excess deaths due to lack of available care.

I'm pretty sure all the family members of the people who died would regard their loved ones as "excess deaths". Your technocratic language ascribes no value to the lives lost, in which case of course the actions seem excessive. For people who don't value the lives of others, it would be hard to understand all the fuss.

This isn’t a disease for which “flattening the curve” makes particular sense. That would require there actually be an effective treatment.

This is a self-contradictory statement. The whole point of flattening the curve is to buy time to develop exactly those effective treatments. It is also possible to flatten the curve to an extent that there are fewer deaths under it, and based on the continual downward revision of the IHME model fatality estimates, that appears to be exactly what is happening.

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

#646

Post by mlyle » Fri, Apr 24, 2020, 3:49 PM UTC

mlthoughts2018 wrote: post #631

mlyle wrote: post #594

Earlier quoted context omitted.

I don't think anyone disagrees that the sample has bias. On the other hand, since the majority of people have no choice but to grocery shop in person, I do not think the sample is as tilted as you imply. And even if it were--- it's notable that it's this easy to find a subgroup with cleared infections this far above what was anticipated to be found across NY/NYC. And-- it's remarkably consistent with statistical esti…

> “ since the majority of people have no choice but to grocery shop in person” This is deeply flawed. I live in NYC and have been making donations to have food delivered to elderly people since this started. Just the other day, de Blasio announced that taxi and rideshare drivers would be paid by the city to deliver food - and city agencies would be serving as overflow dispatchers and tech support for it. Many, many p…

> and in most cases the test specificity is on par with the incidence rate itself,

????? We can't exclude that specificity may be 97% (it's unlikely, based on our data, but it's at the edge of the confidence interval), which is unfortunately on par with the studies returning 2-4% positives... but can't exactly explain a return of 21%. Subtract off 4% worst-case false positives from 21%, and where are you?

Since you want to appeal to authority with Gelman, this is what he said about this on his blog: "– Those California studies estimating 2% or 4% infection rate were hard to assess because of the false-positive problem: if a test has a false positive rate of 1% and you observe 1.5% positive tests, your estimate’s gonna be super noisy. But if 20% of the tests you observe are positive, then the false-positive rate is less of a big deal." ... "– In any case, the 20% number seems reasonable. It’s hard for me to imagine it’s a lot higher, and, given the number of deaths we’ve seen already, I guess it can’t be much lower either."

> so that pooling the studies does nothing to overcome the huge uncertainty they suffer in incidence rates.

The case count multiple from the serological study for New York state (and indeed, the California counties) is right in line with what's expected with a variety of statistical measures that were made without relying upon the serological data. So if you even peeked at my source you'd not be making this argument. https://www.medrxiv.org/content/10.1101/2020.04.18.20070821v...

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

#647

Post by mlyle » Fri, Apr 24, 2020, 4:03 PM UTC

camgunz wrote: post #602

arcticbull wrote: post #482

Earlier quoted context omitted.

Young people are also drastically less likely to get severe disease, and drastically less likely to be hospitalized, see FIGURE 1. [1] I find it very suspicious that young people who don't go to the hospital with severe disease would require oxygen or end up with life-long lung injuries. > Everyone needs to stay practice social distancing and shelter, because everyone can carry and spread. Sweden has demonstrated at…

> I find it very suspicious that young people who don't go to the hospital with severe disease would require oxygen or end up with life-long lung injuries. https://www.washingtonpost.com/opinions/2020/04/09/my-near-d... Or I don't know, Google ventilator effects. Lung scarring. Young people get this, and it hurts them, maybe forever. It's not common, but it's absolutely not never, and you can still spread the virus i…

Permanent restrictions, drastic social change, and large contact tracing infrastructure might keep it under the herd immunity threshold of ~60%. It might not, too.

But you can't let up at any point, because it'll still be endemic and ready to explode up to that herd immunity threshold.

I prefer approaches that get us to that 60% in an orderly fashion-- staying short of healthcare overload, and preventing as much infection in the vulnerable as possible.

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

#648

Post by mlyle » Fri, Apr 24, 2020, 4:05 PM UTC

__blockcipher__ wrote: post #537

maxerickson wrote: post #476

Earlier quoted context omitted.

That is not well established. It's likely enough, but we don't gain long term immunity to every virus that we successfully clear.

It is well established. https://en.wikipedia.org/wiki/Memory_T_cell You are conflating active circulating antibodies with the memory T cells. Which is literally what my entire comment was about.

Of course, there's other confounds. Like the somewhat recent discovery that we end up with antigen experience / "memory" of diseases that we've never contracted. (Perhaps from viral fragments in the environment??)

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

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Post by austingulati » Fri, Apr 24, 2020, 4:08 PM UTC

ineedasername wrote: post #557

ineedasername wrote: post #332

Earlier quoted context omitted.

Sure, phone surveys for political purposes (presidential approval ratings etc.) have to deal with that all of the time. There are methods for estimating non-response impact. [0] One method of mitigating it that I've seen it to reach out again to non-responders. You then analyze their results to see how they differ from the baseline responders to estimate the non-responder population. If there's little/no difference,…

Wow, downvoted for providing factual information on how researchers mitigate non-response bias. Didn't think there was anything controversial there. I'm willing to accept the additional downvoted for this comment though.

Not downvoted by me! Appreciate you sharing this information, it is helping me better understand how researchers mitigate non-response bias. Interesting stuff.

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

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Post by CydeWeys » Fri, Apr 24, 2020, 4:27 PM UTC

cm2187 wrote: post #622

CydeWeys wrote: post #514

Earlier quoted context omitted.

You can't assume that. I know plenty of people who haven't left their apartments in a month plus, because they're having groceries ordered in. And you completely missed the point that people who are going outside a lot more often are both (a) more likely to have been exposed to COVID-19, and (b) more likely to be encountered by your survey. If there are e.g. 700 daily shoppers and 700 weekly shoppers going to a given…

The study wasn't one day but one week, and even then, I assume they wouldn't be stupid enough to collect blood from the same person over and over.

There's more than one store in NYC. People shop at a variety of places. Daily shoppers are likely not going to the same store over and over every day. Even during this pandemic I've hit up several different grocery stores and shops, because some things are hard to find.