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Or here's a study of NYC pregnant women (who were in hospital for delivery, not for coronavirus) that found 13.7% positive by PCR (not antibodies, active infect

Or here's a study of NYC pregnant women (who were in hospital for delivery, not for coronavirus) that found 13.7% positive by PCR (not antibodies, active infection): https://www.nejm.org/doi/full/10.1056/NEJMc2009316 https://www.nejm.org/doi/full/10.1056/NEJMc2009316 Verity et al. estimated IFR around 0.6% back in March, based on stuff like the Diamond Princess, again no antibody tests: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30243-7/fulltext https://www.thelancet.com/journals/laninf/article/PIIS1473-3... This is broadly consistent with the latest serology. NYC implies a bit worse if we divide excess deaths by antibody positives (though they haven't published their methodology as far as I know). Preprints from many European countries imply a bit better. And ~0.2% of NYC is dead from coronavirus by now. So if less than 5% of the city has had it, you think IFR is >4% there? And you think NYC's announced serology data is ~15% false positives? Even though the total positive rate--which would include both true and false positives--in serology studies in most other cities (which haven't been hit nearly as hard as NYC) is far less than 15%? This makes no sense at all. The simple explanation for Korea's high CFR is that for a disease where most countries have failed to trace ~100% of the cases, they're failing to trace about half. I think I've seen their public health authorities speculate exactly that, though I can't find the link now. Inciting public panic is a different kind of harm from inciting public complacency, but it's harm nonetheless. I urge you to correct the misinformation you've posted above. ETA: And really any single IFR is inherently misleading for this disease--the IFR climbs so steeply with age that it will vary greatly with population age structure, and with whether the disease disproportionately hits the most vulnerable (like when it spreads in nursing homes) or least (which should be our goal, since if we're unable to avoid herd immunity from recovered cases before a vaccine comes then that will cost the fewest deaths). But that's what was discussed above, so I stuck with it.

joshuamorton 6y ago
> And ~0.2% of NYC is dead from coronavirus by now You're confusing NYC and NY State numbers. .1% of NYC is dead from Covid at the moment. Which leads to an IFR of 2%, an IFR which falls in line, if a bit above those expected in South Korea etc. > Inciting public panic is a different kind of harm from inciting public complacency, but it's harm nonetheless. I urge you to correct the misinformation you've posted above. I agree. Can you explain what about what I've said might incite a public panic? I believe all I've said is that everything I've said can be traced back to two basic assumptions: - I think it's reasonable to believe that the IFR is among the high end of expert estimates - Naive reading of many serology studies leads to the conclusion that something like 80% of Covid cases are completely asymptomatic. This is likely untrue and believing it leads to dangerous conclusions. > Even though the total positive rate--which would include both true and false positives--in serology studies in most other cities (which haven't been hit nearly as hard as NYC) is far less than 15%? Indeed, in most it is. And then there's the study that showed 60% positive serology in a city in France, and 30% positive serology in Massachusetts. So yeah a 10% or 12% false positive rate in a serology study is completely feasible, given that the French study probably had a 40% false positive rate or something equally ridiculous.
- tripletao 6y ago
  How did you calculate your 0.1%? NYC is 8,340,000 people[1]. They report 14,753 confirmed deaths, plus 5,178 probable[2]. That's 0.24%. Excess deaths (above expected baseline mortality) are yet higher. I don't believe a binary symptomatic/asymptomatic distinction is terribly useful. I agree that most cases that are tracked eventually report symptoms, just symptoms that are mild enough they wouldn't normally have sought medical care (in normal times, because they wouldn't bother; or now, because they're afraid to go to hospital). That seems entirely consistent with the serology studies. You originally said: > There are basically no (larger than a single building) places that can legitimately claim 5% or higher infection rates I believe that's very, very false--NYC's official numbers are around 4x that already, and those imply an IFR consistent with (and even higher than) estimates like Verity's. To claim even 2% IFR seems borderline-irresponsibly high to me, let alone the >4% that implied. If you post links to the studies you mentioned, I can take a look. I believe the Massachusetts one you mention is Chelsea, which indeed found a very high rate; but subjects were approached in a public place (thus oversampling people with higher-risk behavior), in a particularly hard-hit neighborhood. So I'd guess its results are correct for the people sampled, but not representative of the overall city. Have you studied how the specificity of antibody tests is validated, like on blood banked before the emergence of the virus? Why don't you think that validation is adequate? I agree that the correctly-calculated confidence interval for something like the Santa Clara study is near-uselessly wide, but I don't see any reason to doubt serology from harder-hit areas. 1. https://www1.nyc.gov/site/planning/planning-level/nyc-population/nyc-population.page https://www1.nyc.gov/site/planning/planning-level/nyc-popula... 2. https://www1.nyc.gov/site/doh/covid/covid-19-data.page https://www1.nyc.gov/site/doh/covid/covid-19-data.page
  - joshuamorton 6y ago
    > Have you studied how the specificity of antibody tests is validated, like on blood banked before the emergence of the virus? Why don't you think that validation is adequate? I agree that the correctly-calculated confidence interval for something like the Santa Clara study is near-uselessly wide, but I don't see any reason to doubt serology from harder-hit areas. Yes, my understanding is two-fold. One, that independent verification (like https://covidtestingproject.org/ https://covidtestingproject.org/) found less specificity than the manufacturer reported results. And it found that some tests had false positive rates of well over 10%, which is just completely useless. The Santa Clara study is useless with pretty much any test, but even some of the NYC numbers have error bars down to zero, depending on the serology test used. > in a particularly hard-hit neighborhood. So I'd guess its results are correct for the people sampled, but not representative of the overall city. I can and do also totally believe conclusions like this are possible: I'm sure that there are population subsets that have achieved near total immunity. I don't particularly doubt the conclusions of the Boston homeless study, for example, although I expect if we check back in on them, many will have reported symptoms and some will be hospitalized. But again, drawing conclusions about "we should reopen" from that kind of thing is irresponsible. > I believe that's very, very false--NYC's official numbers are around 4x that already, and those imply an IFR consistent with (and even higher than) estimates like Verity's. To claim even 2% IFR seems borderline-irresponsibly high to me, let alone the >4% that implied. It looks like you're correct, the data I was looking at was wrong/outdated/I can't read or something. Given that, I would agree that NYC basically has to have 5% infected, and 10% is reasonable, although 20 and 25% I'd still have doubts about (and even more doubts about them given that the data is from ~3 weeks ago). So yes, I'd agree that an IFR of 4% plus is irresponsible to suggest, and I didn't intend to do so.

joshuamorton 6y ago

> And ~0.2% of NYC is dead from coronavirus by now You're confusing NYC and NY State numbers. .1% of NYC is dead from Covid at the moment. Which leads to an IFR of 2%, an IFR which falls in line, if a bit above those expected in South Korea etc. > Inciting public panic is a different kind of harm from inciting public complacency, but it's harm nonetheless. I urge you to correct the misinformation you've posted above. I agree. Can you explain what about what I've said might incite a public panic? I believe all I've said is that everything I've said can be traced back to two basic assumptions: - I think it's reasonable to believe that the IFR is among the high end of expert estimates - Naive reading of many serology studies leads to the conclusion that something like 80% of Covid cases are completely asymptomatic. This is likely untrue and believing it leads to dangerous conclusions. > Even though the total positive rate--which would include both true and false positives--in serology studies in most other cities (which haven't been hit nearly as hard as NYC) is far less than 15%? Indeed, in most it is. And then there's the study that showed 60% positive serology in a city in France, and 30% positive serology in Massachusetts. So yeah a 10% or 12% false positive rate in a serology study is completely feasible, given that the French study probably had a 40% false positive rate or something equally ridiculous.

tripletao 6y ago
How did you calculate your 0.1%? NYC is 8,340,000 people[1]. They report 14,753 confirmed deaths, plus 5,178 probable[2]. That's 0.24%. Excess deaths (above expected baseline mortality) are yet higher. I don't believe a binary symptomatic/asymptomatic distinction is terribly useful. I agree that most cases that are tracked eventually report symptoms, just symptoms that are mild enough they wouldn't normally have sought medical care (in normal times, because they wouldn't bother; or now, because they're afraid to go to hospital). That seems entirely consistent with the serology studies. You originally said: > There are basically no (larger than a single building) places that can legitimately claim 5% or higher infection rates I believe that's very, very false--NYC's official numbers are around 4x that already, and those imply an IFR consistent with (and even higher than) estimates like Verity's. To claim even 2% IFR seems borderline-irresponsibly high to me, let alone the >4% that implied. If you post links to the studies you mentioned, I can take a look. I believe the Massachusetts one you mention is Chelsea, which indeed found a very high rate; but subjects were approached in a public place (thus oversampling people with higher-risk behavior), in a particularly hard-hit neighborhood. So I'd guess its results are correct for the people sampled, but not representative of the overall city. Have you studied how the specificity of antibody tests is validated, like on blood banked before the emergence of the virus? Why don't you think that validation is adequate? I agree that the correctly-calculated confidence interval for something like the Santa Clara study is near-uselessly wide, but I don't see any reason to doubt serology from harder-hit areas. 1. https://www1.nyc.gov/site/planning/planning-level/nyc-population/nyc-population.page https://www1.nyc.gov/site/planning/planning-level/nyc-popula... 2. https://www1.nyc.gov/site/doh/covid/covid-19-data.page https://www1.nyc.gov/site/doh/covid/covid-19-data.page
- joshuamorton 6y ago
  > Have you studied how the specificity of antibody tests is validated, like on blood banked before the emergence of the virus? Why don't you think that validation is adequate? I agree that the correctly-calculated confidence interval for something like the Santa Clara study is near-uselessly wide, but I don't see any reason to doubt serology from harder-hit areas. Yes, my understanding is two-fold. One, that independent verification (like https://covidtestingproject.org/ https://covidtestingproject.org/) found less specificity than the manufacturer reported results. And it found that some tests had false positive rates of well over 10%, which is just completely useless. The Santa Clara study is useless with pretty much any test, but even some of the NYC numbers have error bars down to zero, depending on the serology test used. > in a particularly hard-hit neighborhood. So I'd guess its results are correct for the people sampled, but not representative of the overall city. I can and do also totally believe conclusions like this are possible: I'm sure that there are population subsets that have achieved near total immunity. I don't particularly doubt the conclusions of the Boston homeless study, for example, although I expect if we check back in on them, many will have reported symptoms and some will be hospitalized. But again, drawing conclusions about "we should reopen" from that kind of thing is irresponsible. > I believe that's very, very false--NYC's official numbers are around 4x that already, and those imply an IFR consistent with (and even higher than) estimates like Verity's. To claim even 2% IFR seems borderline-irresponsibly high to me, let alone the >4% that implied. It looks like you're correct, the data I was looking at was wrong/outdated/I can't read or something. Given that, I would agree that NYC basically has to have 5% infected, and 10% is reasonable, although 20 and 25% I'd still have doubts about (and even more doubts about them given that the data is from ~3 weeks ago). So yes, I'd agree that an IFR of 4% plus is irresponsible to suggest, and I didn't intend to do so.