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Covid-19 Antibody Seroprevalence in Santa Clara County, California

medrxiv.org

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Re: Covid-19 Antibody Seroprevalence in Santa Clara County, California

#201

Post by microdrum »

ysleepy wrote: post #62
microdrum wrote: post #47

Earlier quoted context omitted.

Yep. You've got nothing. CFR is low, and this has been knowable for a long time. You're scared. It's OK. It's illogical and anti-scientific, but it's OK. But you won't be able to hurt ordinary people any longer. Here's Germany's imputed CFR: https://spectator.us/covid-antibody-test-german-town-shows-1... Here's Denmark: https://www.dr.dk/nyheder/indland/doedelighed-skal-formentli... Here's Iceland: https://reason.com…

You are oversimplifying. While these numbers are indicators, they are non-representative samples. Different communities spread the disease to different demographics. A CFR of 0.4% is still huge, especially if it is very non-uniform and would mean 1.2mio deaths in the US if it saturates. And if that isnt enough for you, we still don't have reliable information about long term effects of an infection. It could end up b…

"if it saturates"

That sequence of words shows you do not know the basics of epidemiology. Epidemics do not affect 100% of a population.

Re: Covid-19 Antibody Seroprevalence in Santa Clara County, California

#202

Post by microdrum »

yread wrote: post #76
microdrum wrote: post #47

Earlier quoted context omitted.

Yep. You've got nothing. CFR is low, and this has been knowable for a long time. You're scared. It's OK. It's illogical and anti-scientific, but it's OK. But you won't be able to hurt ordinary people any longer. Here's Germany's imputed CFR: https://spectator.us/covid-antibody-test-german-town-shows-1... Here's Denmark: https://www.dr.dk/nyheder/indland/doedelighed-skal-formentli... Here's Iceland: https://reason.com…

Few non-peer reviewed papers with biased samples, questionable tests and questionable methodology don't make strong evidence. CFR just can't be that low. There are towns in Italy where the virus killed 1% of total population https://www.ecodibergamo.it/stories/valle-brembana/il-grido-...

It sure can be that low. Pretty simple reason, too:

1) Studies linked above are properly statistically randomized 2) Italy population dead = old smokers, Chinese from Wuhan working in factories

The study is a random population sample. A single tiny town Italy has a highly characterized population. If you disagree, you've never been to Italy.

Stop being scared. Start being logical.

Re: Covid-19 Antibody Seroprevalence in Santa Clara County, California

#203

Post by microdrum »

DanBC wrote: post #60
microdrum wrote: post #47

Earlier quoted context omitted.

Yep. You've got nothing. CFR is low, and this has been knowable for a long time. You're scared. It's OK. It's illogical and anti-scientific, but it's OK. But you won't be able to hurt ordinary people any longer. Here's Germany's imputed CFR: https://spectator.us/covid-antibody-test-german-town-shows-1... Here's Denmark: https://www.dr.dk/nyheder/indland/doedelighed-skal-formentli... Here's Iceland: https://reason.com…

Why quote Denmark but ignore Sweden? Sweden are doing what you're calling for, and they have pretty high numbers of deaths.

No they don't. Stop being scared. Start being logical.

Re: Covid-19 Antibody Seroprevalence in Santa Clara County, California

#204

Post by microdrum »

microdrum wrote: post #40

This is very strong evidence that the "realists" like Alex Berensen were correct. The shutdowns probably should end, while encouraging at-risk populations (mostly retired) to stay at home.

The anti-science on HN is astounding.

Re: Covid-19 Antibody Seroprevalence in Santa Clara County, California

#205

Post by microdrum »

jhayward wrote: post #123
microdrum wrote: post #40

This is very strong evidence that the "realists" like Alex Berensen were correct. The shutdowns probably should end, while encouraging at-risk populations (mostly retired) to stay at home.

Data from Wuhan was that in the early phase of the epidemic about 70% of infections were transmitted at home. Once they realized this, they went to rapid isolation of positive tests and quarantine of contacts in “COVID hotels” away from home. So your suggestion is entirely unworkable unless there is a plan to remove all at-risk persons from contact with low-risk persons. Please show your work and let us know what tha…

Guess what? We have been doing it your way for 45 days. Everyone infected is now locked in a house with others. They too are now infected. Intrafamilial and nosocomial infection is much more powerful than community -- that has been proven here and in earlier epidemics.

And yet anti-science morons in SF clutch their scarf over their mouths when you jog past them.

Re: Covid-19 Antibody Seroprevalence in Santa Clara County, California

#206

Post by cameldrv »

mlyle wrote: post #173
irq11 wrote: post #143

Earlier quoted context omitted.

That is just nonsense. You don’t adjust for demographic bias in a sample by conditioning on a second parameter. There’s no universe in which underweighting the underweighted group makes any sense at all. Moreover, there isn any support for the idea that “bored white women” are more or less likely to get tested for symptomatic illness than anyone else. Your entire argument boils down to “I don’t like the implications…

I do think it's likely the study does overreport the infection rate. People who are really curious about their past COVID-19 status are not representative of the population as a whole. And stratified sampling can help to try and correct this, but... we all know that you can't really "save" or "fully condition" a convenience sample. On the other hand, it's hard to reconcile their finding with anything less than 90% or…

I agree that cases are probably giving maybe a 10-20x undercount. That means that NYC has maybe 3 million infections. That means NYC is maybe half way to herd immunity, assuming reinfection doesn't happen and that immunity is lasting.

The only problem is that to get the other half way there, another 20,000 people have to die, just in New York City. That doesn't even count the already existing infections that haven't died yet.

Re: Covid-19 Antibody Seroprevalence in Santa Clara County, California

#207

Post by mlyle »

Medicalidiot wrote: post #196
mlyle wrote: post #179

Earlier quoted context omitted.

It's not a random sample; it's a convenience sample of people who responded to Facebook ads.

What about Facebook ads doesn't mean that they're an adequate sample? Is there a confounding factor that you have in mind?

Many confounding factors. Socioeconomic factors that can't be fixed with stratified sampling (access to transportation, usage of Facebook, etc.. conversely the willingness of a $10 amazon gift card to motivate people to participate will vary). People who are concerned about possible past exposure to COVID-19 may have a different probability to respond.

Of course, the bigger issue is that we can't rule out that the antibody tests have a false positive rate that can explain the whole result. We need serology tests in places with a higher positive rate to know.

Basically, 50 positive results out of 3330 is a really small signal. Just a small false positive rate or sampling issue could explain all the positive results.

Re: Covid-19 Antibody Seroprevalence in Santa Clara County, California

#208

Post by mlyle »

cameldrv wrote: post #206
mlyle wrote: post #173

Earlier quoted context omitted.

I do think it's likely the study does overreport the infection rate. People who are really curious about their past COVID-19 status are not representative of the population as a whole. And stratified sampling can help to try and correct this, but... we all know that you can't really "save" or "fully condition" a convenience sample. On the other hand, it's hard to reconcile their finding with anything less than 90% or…

I agree that cases are probably giving maybe a 10-20x undercount. That means that NYC has maybe 3 million infections. That means NYC is maybe half way to herd immunity, assuming reinfection doesn't happen and that immunity is lasting. The only problem is that to get the other half way there, another 20,000 people have to die, just in New York City. That doesn't even count the already existing infections that haven't…

Maybe this time we can do a better job of concentrating the infections in the less-likely-to-die group, and cut down on the deaths a little that way.

Re: Covid-19 Antibody Seroprevalence in Santa Clara County, California

#209

Post by DiogenesKynikos »

compiler-guy wrote: post #50
gryson wrote: post #37

Earlier quoted context omitted.

What adjustments were made to account for selection bias of the sort described? It's not covered in the paper, and "well-established science" certainly doesn't answer the question.

These are very common statistical methods when dealing with surveys and populations. It isn't this paper's job to describe the background on something like that, just like it isn't this papers job to explain blood testing. They describe their limitations and adjustments exactly like most other studies of this sort do. For example: "Those imbalances were partly addressed by weighting our sample population by zip code,…

That reweighting doesn't address the most troubling selection bias: people choosing to participate because they want to get tested (e.g., because they think they might have had the disease).
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