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Covid-19 Antibody Seroprevalence in Santa Clara County, California

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

#41

Post by war1025 »

not2b wrote: post #32
rumanator wrote: post #29

Earlier quoted context omitted.

I don't follow your argument. If the epidemic is more widespread than initially thought, why do you assume that the effective transmission rate would potentially decrease? If anything, the transmission rate was higher than assumed and, due to the higher number of infections and how they spread exponentially,it would only ramp up. And additionally, there are reports of reinfections among covid19 patients who were foun…

There's good news and bad news: the good news is the more cases that are found from people who didn't know they had it, the less deadly the disease is. The bad news: if it's all over the place it will be really hard to stamp it out.

I assume it's endemic at this point and we just need to learn how to live with it. Society can brace for a storm, but at some point you need to adapt and learn to live with the weather.

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

#42

Post by networkimprov »

gryson wrote: post #18

"We recruited participants by placing targeted advertisements on Facebook aimed at residents of Santa Clara County..." I wonder if these ads mentioned the purpose of the study, or if that information was only given out after initial contact (I don't know enough about IRB requirements here). A concern is that this could cause a selection bias for people who suspected they had the virus. People may respond to such an a…

In the data from Italy, ~14% of the >1M tests done for the virus (not antibodies) were positive. That prob includes ppl tested multiple times, or after recovery.

I wonder why this is so vastly different from the study above.

https://en.wikipedia.org/wiki/2020_coronavirus_pandemic_in_I...

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

#43

Post by cdelsolar »

timr wrote: post #39
rumanator wrote: post #29

Earlier quoted context omitted.

I don't follow your argument. If the epidemic is more widespread than initially thought, why do you assume that the effective transmission rate would potentially decrease? If anything, the transmission rate was higher than assumed and, due to the higher number of infections and how they spread exponentially,it would only ramp up. And additionally, there are reports of reinfections among covid19 patients who were foun…

"If the epidemic is more widespread than initially thought, why do you assume that the effective transmission rate would potentially decrease?" Herd immunity. If testing is only detecting 1/50th of cases in NYC, for example, it means that there have been about 6M cases, or about 69% of NYC's population. That's basically the threshold where we'd expect to see the infection counts level off naturally.

there is no herd immunity if reinfection can occur, which appears to be the case

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

#44

Post by dmitriy_ko »

sxp wrote: post #14

There are similar high infection rates from other semi-randomized samples. https://www.nejm.org/doi/full/10.1056/NEJMc2009316 > Between March 22 and April 4, 2020, a total of 215 pregnant women delivered infants at the New York–Presbyterian Allen Hospital and Columbia University Irving Medical Center . All the women were screened on admission for symptoms of Covid-19. Four women (1.9%) had fever or other symptoms of…

So 15% infection rate among pregnant women. I would assume pregnant women would be more careful than average about avoiding getting infected. So overall infection rate in New York City must be even higher.

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

#46

Post by slg »

pwned1 wrote: post #36
slg wrote: post #24

Earlier quoted context omitted.

California has 2X the population of New York. NY has more than 17X the number of deaths and while the daily deaths rate there is slowing it still far outpaces CA's daily rate. I don't know how you can look at those numbers and conclude the disease was spreading unchecked in California for multiple months.

Maybe a milder form of it came directly from Wuhan to CA, spreading like a bad flu. And then the version in NY came from Wuhan to Europe to NY, mutating along the way, and making it more deadly.

I'm not sure why we should believe the strain that originated in Wuhan was milder, but lets go with this theory for a minute. How does the nursing home in Washington fit into that picture? It was one of the earliest known hotspots in the US and it was extremely deadly. Was it the mild strain that you think might have already been spreading through California or the severe strain from Europe that spread to Washington first before New York? If it was the former, why didn't we see similar situations in California among vulnerable populations?

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

#47

Post by microdrum »

cdelsolar wrote: post #45
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.

nope.

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/2020/04/03/what-we-should-have-learned-fr...

More studies coming next week from LA.

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

#48

Post by timr »

ortusdux wrote: post #23
h2odragon wrote: post #3

I think the numbers will coma out to show this ripped through the USA in February; we slammed the barn doors closed well after the horse was gone. Of course that's not the narrative that fits agendas so just like with "why cant we test people?" back then, there will be many official reasons not to look for antibody data and to doubt what data gets gathered.

I keep hearing this sentiment, but I cannot square it with the fact that a non-trivial percent of infected people need to be on ventilators for roughly 20 days. If, back in December, 10k people had what we now know as Covid, there would have been dozens of people on ventilators for weeks at a time in January. The average flu patient needing intubation is only on a ventilator for about 5 days. I just don't see a situa…

All of the flu surveillance numbers suggested a historically bad season this year, and there was a big peak in flu-like mortality in February. It's entirely possible that we were mis-characterizing the data:

https://gis.cdc.gov/grasp/fluview/mortality.html

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

#49

Post by projektfu »

georgewfraser wrote: post #31

There are now multiple sources of evidence pointing to a very low true infection fatality rate, as low as 0.1% in some regions. Iceland has been testing a semi-random sample using PCR since early in the epidemic, and there have been several small antibody surveys in “hot spots” showing infection rates over 15%. You can also use CDC surveillance of flu-like illnesses to estimate the total number of infected nationwide…

It may have a low overall fatality rate, yet it seems to have a high rate of hospitalization in clinical cases.

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

#50

Post by compiler-guy »

gryson wrote: post #37
not2b wrote: post #30

Earlier quoted context omitted.

Yes, the ads accurately described the study. Several friends of mine participated (I live in Santa Clara County). Of course there is selection bias, which is why they make adjustments to make the sample better represent the population (see the abstract for details on this, or read the paper for all the details, there's well-established science behind these adjustments and it's up to the reviewers to be sure that they…

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, race, and sex to match the county. "

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