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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

#471

Post by mlyle »

mynegation wrote: post #424
slg wrote: post #386

Earlier quoted context omitted.

I'm no expert here, so someone can correct me if I am wrong. But I believe as long as each infected person spreads it to more than 1 other non-infected person the disease will continue to spread until there is a herd immunity level of infections. That spread rate will decrease as more people have antibodies, but it seems unlikely to get below 1 since even all the stay at home orders haven't been able to get that numb…

Sustained spread of the infection stops when percentage of people having immunity is 1-1/R0. So if R0 for Covid-19 is (hypothetically) 3, you need 67% immunity to reach herd immunity. For highly contagious diseases like smallpox that number is very close to 100%

Yes, but there's a world of difference between Rt=1.5 and Rt=2.5, both in the degree of controls necessary to bring Rt close to 1 and in how far it can get out of hand if your controls are somewhat insufficient.

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

#472

Post by FlyMoreRockets »

kgwgk wrote: post #450
TheBlight wrote: post #443

Earlier quoted context omitted.

How do you know how often these people are leaving their homes? Everyone has to leave their home to go to the grocery store eventually or someone in their family does. Yes there are delivery services but the vast majority of people aren't using those.

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.

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

#473

Post by mlyle »

qqqwerty wrote: post #470
mlyle wrote: post #404

Earlier quoted context omitted.

> If IFR is low, then that means R0 is way higher than we thought, which also means isolating only the vulnerable will not work. No. If you miss a constant percentage of cases, you get the same shape of exponential curve. That is, a virus with an R0 of 2 and 1 case doubling to 2 and 2 cases doubling to 4.... looks the same when you miss 99% of infections and see 1 of 100 infections doubling to 2 of 200 doubling to 4…

> If you miss a constant percentage of cases We are talking about 1 serological study at a single point in time. We have no idea what percentage of cases we were missing before or after that point.

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 opposite of what you're saying, and argues for lower R0.

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

#474

Post by maxerickson »

__blockcipher__ wrote: post #387
slg wrote: post #360

Earlier quoted context omitted.

>There are many more infections than we know about and the CFR is not anywhere close to the actual IFR. That is the optimistic takeaway. The pessimistic takeaway is that even the hardest hit areas are nowhere near herd immunity levels and that we are either going to be isolating until a vaccine is created or we can expect to see a lot more death once nonessential people are forced back to work.

At this point people advocating the position you’re advocating for are in a state of denial (this is my opinion, not a matter of fact, obviously). Your assumption is that we can effectively prevent the majority of the nation from exposure via lockdown. Not only does evidence seem to point against that, but when you do the math on mortality due to suicide and overdose it’s not clear that containment would even save mo…

It's not like business was going to go on as normal when people started filling up hospitals.

The lock down was a choice between what we are going through now and a much worse disaster if the spread continued through a couple more doublings. Of course the extreme stay at home orders should be continued for as short a time as possible, but what we do next also doesn't have to be exactly what we were doing before (and realistically won't be).

My impression at the moment is that containment isn't going to happen, but mostly because people don't want to bother, not because it is the more costly alternative or impractical. Given the lack of appetite to test and isolate, we had better all start doing things like wearing masks.

Note that ~80% of American's favor the stay at home orders right now. It's not a partisan issue, it's an issue where a loud minority is getting some attention from the media.

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

#475

Post by walterbell »

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…

> Preliminary test results suggest 21% of of people approached in a crowded grocery store and who would agree to give blood have Covid antibodies

Would be useful to know how many deaths from the same zip codes are people who visited crowded grocery stores.

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

#476

Post by maxerickson »

__blockcipher__ wrote: post #444
badfrog wrote: post #385

Earlier quoted context omitted.

> The closer we get, the better it is. Having 21% "immune" leads to far different outcomes than .1%. It depends on how long the immunity lasts. If it's permanent, this is indeed great. If it lasts only a few months, this 21% won't make any difference for another wave of infections this fall.

We use the term "immunity" but we should remember that there is a difference between the presence of active antibodies and the presence of immune "memory cells". The latter hang around long-term, even if the former disappear. So at a minimum if one does develop infection they will recover far sooner and with better outcomes. And likely will reach a far lower peak viral load which might bring down transmission.

That is not well established.

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

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

#477

Post by kgwgk »

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.

I don’t get your point. Maybe we agree. If in one city there are 1000 30-year-old daily-shopers, 1000 50-year-old weekly-shoppers and 1000 70-year-old monthly-shoppers it will not be a good idea to estimate the age of the population by sampling people who enters the store. The average age is 50, not 34.

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

#478

Post by tunesmith »

DeonPenny wrote: post #132
SpicyLemonZest wrote: post #83

Earlier quoted context omitted.

I agree, but this is not universally believed. Many people argue that hospital capacity is not what matters, and we must continue lockdowns even if hospitals won't be overloaded to eradicate the disease.

But if that held then we'd eradicate flu and the common cold two. Quarantines don't eradicate disease they slow the spread but the area under the curve is constant. I doubt will change the number of infected is a constant regardless of the rate.

That's only true if medical and technological advancements don't happen. A vaccine a year from now means less death if we've locked down in the meantime, compared to if we haven't locked down. Similarly, if we scale up testing and contact tracing to the point we can eventually eradicate the disease through targeted quarantines, a preceding lockdown means less death.

If instead we don't experience any advancements, then right, it just means the same number of infections are spread out over a longer period of time.

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

#479

Post by mlyle »

slg wrote: post #465
mlyle wrote: post #454

Earlier quoted context omitted.

Table 2: https://www.cdc.gov/nchs/nvss/vsrr/covid19/index.htm The statement you differed with is "The third option is, when you take into account that it's approximately as bad as the flu for folks under 40," You're ignoring data in order to make a wishy-washy statement that it must be much worse for people under 40 based on anecdotes you hear. I don't agree flu infections were higher for those 2 months, either. Dist…

First off, all those numbers are once again absolute deaths and not related to case numbers so my prior complaint still stands. If you look at the first chart, you will see that COVID-19 deaths didn't start becoming a problem until March. Distancing practices were not widespread until mid-March. Meanwhile flu deaths weren't dramatically cut until the most recent timeframe. So taking into consideration both the first…

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).

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

#480

Post by camgunz »

__blockcipher__ wrote: post #448
slg wrote: post #405

Earlier quoted context omitted.

I skimmed through that so please point it out if I missed it, but the numbers don't seem to account for comorbidities. The question was whether COVID-19 is more dangerous than the flu to healthy young people not all young people.

Well even with your qualifier of "no comorbidities", the evidence is pretty unanimous that Covid and Influenza are not even the same ballpark. Worrying about a healthy young person dying of Covid is more akin to worrying about a healthy young person dying of cancer than it is to bacterial meningitis or something. As I've said elsewhere, Influenza is defined by being deadly to the very young and very old, and so-so to…

> Unfortunately, and I know people read this stuff and their quack heuristics start firing, the reason people are so afraid about Covid's impact on young people is because the mainstream media has intentionally promulgated a narrative that "young people are at risk too" because they fear that otherwise young people wouldn't submit to glorified house arrest for months straight.

They've reported that because young people who very likely won't die from COVID-19 (they may still need to be put on oxygen and may have lifelong effects from it, but they likely won't die) can still spread it to those that will. Further, they'll put more strain on the health system, and the ability to care for COVID-19 patients is a big determinant in the fatality rate. Everyone needs to stay practice social distancing and shelter, because everyone can carry and spread.

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