Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

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

6sqft.com

Post reply on HN
Print view View original

491–500 of 679 posts

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

#491

Post by urda »

mrb wrote: post #183

If this study is accurate, then 1.8 million NYC resident are infected. So 15 411 deaths (as of today, including 5 121 probable deaths) suggests COVID-19 has a fatality rate of MINIMUM 0.9% which is in line with previous estimates (between 0.5 and 1.6%) and this is MINIMUM 9 times more fatal than the flu (0.1%). Edited to add "MINIMUM", as there is a lag between case detection and death (I should have known better to…

Please don't use uppercase for emphasis. If you want to emphasize a word or phrase, put asterisks around it and it will get italicized.

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

#492

Post by nodamage »

zaroth wrote: post #338
athrowaway3z wrote: post #297

Earlier quoted context omitted.

What? All of these numbers are inline with what experts have been saying and modeling for more than a month. We will be dealing with this for at least another year. We will cycle through policy to loosen up and close back down a little. In the best case for NYC they are 1/4th of the way to herd immunity in numbers. With the drop in transmissions, this might be 1/8th of the way in terms of time. There will be more dea…

25% prevalence is absolutely not in line with what experts were saying on March 23rd. Nor was an IFR of 0.5%. The CDC reports that flu has an IFR of ~.13% in the US (61,000 deaths out of 45 million cases). That makes 0.5% roughly 3.3 times worse, not 10. Also, herd immunity does not require 100% having positive antibodies, it will show an effect on Ro starting around 65%.

Bear in mind that the CDC estimate of 45 million influenza cases[1] is the number of symptomatic cases, and therefore it doesn't really make sense to directly compare that with Covid-19 IFR rates calculated from antibody studies which include both symptomatic and asymptomatic cases.

[1] https://www.cdc.gov/flu/about/burden/2017-2018.htm

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

#493

Post by jdavis703 »

FlyMoreRockets wrote: post #472
kgwgk wrote: post #450

Earlier quoted context omitted.

The more often they go, the more likely you encounter them.

True, but if you encounter one daily shopper, two weekly shoppers and twenty monthly shoppers, it will skew the results. Same if the numbers are reversed.

Most people in NYC are almost certainly not shopping monthly because of storage constraints. Even bi-weekly shopping is likely to exhaust storage space for city-dwellers in small apartments.

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

#494

Post by credit_guy »

hcknwscommenter wrote: post #376
matwood wrote: post #362

Earlier quoted context omitted.

> the Bayesian prior is that common colds in general become less prevalent during the Summer, and Covid19 is caused by a coronavirus, which is related to viruses causing the common cold MERS is also a coronavirus and does just fine in the warm climate of the middle east. I hope that warmer temps slow the spread, but it's far from certain.

It's not just far from certain. It is simply unlikely. The "hypotheses" for explaining seasonal variations in transmissibility are nothing but a wild-guess/hope.

Kinshasa, the capital of DR Congo, is a city with 11 million people. About the same size as Wuhan or New York City. According to [1] there were only 25 deaths due to Covid19 in the whole country. Why so few? 21 million people live in Lagos, Nigeria, yet the whole of Nigeria has seen only 31 deaths. On the other hand, I have to admit, there were quite a bit more deaths in Sao Paolo, Brazil, but it's still an order of magnitude less than in the New York State.

Maybe Africa and Brazil are faking the numbers, but Australia most likely not. Only 76 deaths so far. Argentina has recorded only 159 deaths.

You could say this is only circumstantial evidence. My point is that we are not trying to prove things "beyond any reasonable doubt". We are trying to form the most informed opinion. And there are quite a few factors that point in the direction of reduced infectiousness during the Summer. Schools closed? Check. People away for vacations? Check. More UV light which kills airborne viruses? Check. People having more vitamin D in their bodies? Check. Air more humid, so the tissue inside your nose is better protected? Sure thing. Better immune systems due to less stress due to the ambient light? Sure thing. Etc, etc.

You can question any of these things. But in a Bayesian framework they tilt the scales little by little. But that's just me.

[1] https://news.google.com/covid19/map?hl=en-US&gl=US&ceid=US:e...

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

#495

Post by timr »

zamfi wrote: post #427
TheBlight wrote: post #420

Earlier quoted context omitted.

All three studies created their sample groups differently. Are all three methods flawed in some way? Sure. Is it more reasonable to completely ignore the picture all three are painting or to consider there might be something to the trend?

> Are all three methods flawed in some way? Sure. They're not just all flawed in some way -- along at least one dimension they are flawed in the same way , that is, they all have a biased sample of the population that seems more likely to be infected than a true random sample. So, sure, they're "created differently", i.e., they're not all facebook ads, or grocery stores, but all those methods bias towards higher infe…

These studies have completely different methodologies, and the only way you can plausibly call them similar is by arguing that anyone willing to get serological testing is substantially more likely to be infected than those who are not. That's little more than a fancy way of disregarding any testing result you don't happen to like.

We've been systematically biasing toward testing the old and infected for months now. Why should rates derived from PCR testing with known severity bias considered a strong prior, yet rates derived from serological surveys with hypothetical severity bias be disregarded for the same reasons?

At this point, we have many different studies from different parts of the world -- each with its own methodological flaws and biases -- and yet all are pointing in the same direction: a systematic under-count of cases, and an IFR somewhere between 0.5% and 1%, with a bias toward the lower value.

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

#497

Post by mlyle »

slg wrote: post #489
mlyle wrote: post #479

Earlier quoted context omitted.

We've said approximately as dangerous. It clearly is in a very similar ballpark. We don't have enough data right know to know if it's twice as dangerous for people under age 30, or half as dangerous. (We do already know it's -way less dangerous- for people under age 18).

Ok, maybe this dispute is based on different definitions. I don't think 2X is "approximately", but I do agree that we don't have enough data right now to know the exact difference so I can't say for sure that COVID-19 is more than 2X as dangerous. I also agree that COVID-19 does appear to be way less dangerous for the under 18 group. However practically none of the under 18 group is able to isolate themselves away fr…

> I don't think 2X is "approximately", but I do agree that we don't have enough data right now to know the exact difference so I can't say for sure that COVID-19 is more than 2X as dangerous.

I think we have enough data to exclude more than 2x. The range of potential danger has influenza's risk right in the middle of it.

> I also agree that COVID-19 does appear to be way less dangerous for the under 18 group. However practically none of the under 18 group is able to isolate themselves away from the 18 and over group so there is no real societal benefit to this distinction.

There's a huge societal benefit to this distinction, because if children are at relatively low risk, and also do not seem to be index cases very often for how COVID-19 is spread to households, schools can reopen. This is different from most diseases, where schools are often a key mechanism of disease spread. e.g. see https://www.medrxiv.org/content/10.1101/2020.03.26.20044826v...

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

#498

Post by m3kw9 »

hcknwscommenter wrote: post #349
arrrg wrote: post #334

Earlier quoted context omitted.

The death rate of 0.5% falls right in the range of what modelers have been using, by the way. Not exactly very positive news.

It is very positive in that we can be more confident that our assumptions are close to reality. 0.5%*330M still equals 1.65M deaths, or (very roughly) 5M ICU beds. Spread out over 52 weeks, that's a lot of ventilators and ICU beds and PPE, but it is a target. A very big juicy target that we can and should aim directly at, and HIT.

The issue is you didn’t factor in immunity fading and requiring it again. So those that survive will need to roll dice at a random later date.

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

#499

Post by mannykannot »

wtvanhest wrote: post #451
TheBlight wrote: post #348

Earlier quoted context omitted.

Sure all of these studies are potentially flawed but they're all generally pointing in the same direction. There are many more infections than we know about and the CFR is not anywhere close to the actual IFR. NYC is an outlier with a 21% infection estimate but for the rest of NY (outside NYC metro/Westchester/LI) the estimate is 3.6%. Santa Clara estimate was 3%. LA County estimate was 4%. Seems like a trend is deve…

"Preliminary test results suggest 21% of NYC residents have Covid antibodies" Should be re-written as: "Preliminary test results suggest 21% of of people approached in a crowded grocery store and who would agree to give blood have Covid antibodies" All of these tests suffer the same sample bias, and that sample bias is massive. People who are already in a grocery store (risky behavior), who are willing to give a bloo…

NYC is not suburbia. I believe a higher percentage are still working outside of their homes (and, in many cases, that also means travelling on public transport), and a smaller percentage have the financial and transport resources to significantly reduce the frequency of their shopping trips. Apartment living means a greater exposure to your neighbors whenever you do enter or exit. The sampling in NYC, while far from ideal, may therefore be better than the other regions, in that shopping behaviour may not be as dominant a risk factor as you suppose.

For the same reasons, plus the likelehood that the virus arrived in NYC early and frequently, NYC's figures cannot be extrapolated to the rest of the state or country.

I would like to see how these figures match up to the sewage-sampling method of estimation.

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

#500

Post by mlyle »

qqqwerty wrote: post #488
mlyle wrote: post #473

Earlier quoted context omitted.

There's no reason to interpret the serological study to think a higher R0 is implied, which is what you said. The only way that missing cases affects estimates of R0 from time series is if we're missing a much bigger proportion of cases now than we were in the past. All the evidence I've seen leans the other way-- more testing, better testing, more cases diagnosed by "presumed" criteria. So, it actually implies the o…

I am not interpreting it that way, I believe in the consensus estimates. The parent commenter (articbull) thinks these serological studies (SC, LA, and to a lesser degree NY) prove that the IFR is much lower than we thought because the actual infection numbers are much higher. The NY study, using reasonable assumptions, looks like the IFR might be between 0.5% - 1.0%, but the SC study was claiming 0.1-0.2%. And I am…

> And I am arguing, in the hypothetical case that the SC study is correct (I think it is flawed), then we have under estimated R0.

I don't necessarily believe the Santa Clara County study, but there are plenty of other alternatives, including a pretty likely one: gross undercounting at the start of the epidemic and/or earlier cryptic spread in communities. This is something that SCC public health officials / Dr. Sara Cody has stated in recent days is her belief-- I am not sure I agree.

At this point we're accumulating a lot of evidence IFR is 0.3-0.5%.

Post reply on HN