Crazy (and not-so-crazy) shit about Covid-19

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Re: Crazy (and not-so-crazy) shit about Covid-19

Postby windwalker on Wed Sep 23, 2020 5:57 pm

By applying our theory to the COVID-19 epidemic we found evidence that the hardest hit areas such as New York
City, have likely passed the heterogeneity-modified herd immunity threshold.


Other places that had intermediate exposure, such as e.g. Chicago, while still above the HIT, have their effective reproduction number reduced by a significantly larger factor than predicted by traditional epidemiological models.

This gives a better chance of suppressing the future waves of the epidemic in these locations by less disruptive measures
than those used during the first wave, e.g. by contact tracing, control of potential super-spreading events, etc.

According to our results, a significant suppression of the second wave in both cities is expected even for a rather moderate value of the immunity factor.

https://arxiv.org/pdf/2008.08142.pdf


Significance Statement

This study demonstrates how a wide class of epidemiological models can be adapted for applications to heterogeneous populations in the context of the COVID-19 epidemic. It is shown that a persistent heterogeneity, rather than bursty short-term variations in infection transmission is responsible for self-limiting
epidemic dynamics.

Compact generalizations of the classical results for the herd immunity threshold and the final size
of an epidemic are derived. The degree of persistent heterogeneity is estimated from data on real-life face-to-face contact
networks, and on age variation of susceptibility to COVID-19.

The estimate is further supported by the analysis of the empirical data from the epidemic in NYC and Chicago, as well as in 50 US states.
The results suggest that by the end of the first wave of the epidemic, the hardest-hit areas, such as NYC, have been close to the heterogeneity-modified herd immunity, thereby limiting their vulnerability to a potential second wave of the epidemic.


Ongoing studies suggesting the "herd immunity threshold is much lower than previously thought to be.
Last edited by windwalker on Wed Sep 23, 2020 6:55 pm, edited 1 time in total.
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Re: Crazy (and not-so-crazy) shit about Covid-19

Postby Steve James on Wed Sep 23, 2020 7:12 pm

NYC and state still have restrictions on people coming from other states. If we had "herd immunity," it wouldn't matter. Herd immunity is what vaccines provide. You come to NYC, you can still catch covid. True, the people who've been here since the beginning and haven't been affected are probably good to go.

However, the reality is that there are several neighborhoods in NYC which are having serious problems now. https://www.nbcnewyork.com/news/coronav ... t/2631102/
And, worse, there'll probably be a real "second wave," while people are making happy talk saying it's over.
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Re: Crazy (and not-so-crazy) shit about Covid-19

Postby windwalker on Wed Sep 23, 2020 7:25 pm

Steve James wrote:NYC and state still have restrictions on people coming from other states. If we had "herd immunity," it wouldn't matter. Herd immunity is what vaccines provide. You come to NYC, you can still catch covid. True, the people who've been here since the beginning and haven't been affected are probably good to go.

However, the reality is that there are several neighborhoods in NYC which are having serious problems now. https://www.nbcnewyork.com/news/coronav ... t/2631102/
And, worse, there'll probably be a real "second wave," while people are making happy talk saying it's over.



The estimate is further supported by the analysis of the empirical data from the epidemic in NYC and Chicago, as well as in 50 US states.

The results suggest that by the end of the first wave of the epidemic, the hardest-hit areas, such as NYC, have been close to the heterogeneity-modified herd immunity, thereby limiting their vulnerability to a potential second wave of the epidemic


Persistent heterogeneity not short-term
overdispersion determines herd immunity to
COVID-19

https://arxiv.org/pdf/2008.08142.pdf


The study suggest they may not be as vulnerable to a second wave as some feel.
Last edited by windwalker on Wed Sep 23, 2020 7:28 pm, edited 1 time in total.
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Re: Crazy (and not-so-crazy) shit about Covid-19

Postby LaoDan on Thu Sep 24, 2020 2:36 pm

I think that the speculation about herd immunity is primarily wishful thinking, and far too premature. While we do not know the precise number of individuals in any population that have contracted COVID-19 and been unconfirmed (due to being symptomless or otherwise not being tested, etc.), the confirmed cases in the USA stands at ~7 million out of a population of about 330 million. 7/330 = ~2%, very far from what one would expect would be needed to confer herd immunity. If one doubles, triples, quadruples that number to account for the uncertainties, then we are STILL far below the number needed to confer herd immunity in the USA (and the world – see below). I do not have numbers for NYC, but anyone who does can do the calculation for that specific location.

As an example, please consider the following:

If we assume that 50% of the population is, for various reasons (“dark matter”...), protected against developing an illness from the coronavirus (Karl Friston modeling, which should include things like T-cell resistance, etc.) and apply that to the 1918 “Spanish” flu (H1N1) pandemic, then his numbers seem reasonable. It has been estimated that 1/3 of the world population became infected/sick from the 1918 flu outbreak, and like the current pandemic there was no vaccine and few if any prophylaxis.

We can probably assume that the 1918 pandemic ended (in the summer of 1919) when herd immunity was achieved. But ~30% of a population is far below what is now understood to confer herd immunity, so ~30% (sick) + ~50% (asymptomatic; e.g. Karl Friston modeling) = ~80% of the population needing to be immune/resistant in some fashion to confer herd immunity to the remaining ~20% of the population [note that this percentage falls within the expected range of less than 70% to as much as 90% for herd immunity, depending on the specific disease, and since both H1N1 and the coronavirus are fairly high on their contagiousness, this seems reasonable for both].

Note that even though asymptomatic spread has been known since “typhoid Mary” [1907], in 1918 they did not have the diagnostic capabilities that we do today. Therefore the estimated ~30% that caught the disease was probably only counting those who actually developed noticeable symptoms. Today’s statistics are different since most state “confirmed cases” whether or not those cases showed symptoms. This makes comparisons between 1918 and 2020 difficult. However, I am not aware of a better pandemic to use for comparison.

The above would mean that, of the 7.8 billion current world population, ~3.9 billion may have natural immunity/resistance where symptoms are not noticeable or mild enough to not become ill, ~2.3 billion could be susceptible to infection and illness prior to the virus running its course (after achieving herd immunity) and conferring protection for the remaining ~1.6 billion people. We are nowhere close to that at present since ~32 million confirmed worldwide cases (both symptomatic AND asymptomatic but still confirmed) is far below ~2.3 billion. Of course, the coronavirus may have differences from the H1N1 flu, and could be better or could be worse. Also, different locations could have different exposure levels so some locations will achieve herd immunity earlier that other locations. But speculating that the coronavirus may be significantly less contagious than the H1N1 flu of 1918 seems extremely foolish. I expect a similar ~30% of the population showing symptoms if no mitigating factors were in place.

The above numbers assume that the population was not taking significant protective steps (the masks worn in 1918-1919 were relatively useless in stopping the spread of the 1918 flu pandemic). It is probably safe to state that social distancing, reduced travel, and protective mask wearing would reduce the spread of the current disease, and therefore result in a lowering of the necessary herd immunity %. But it is not known how long these protective measures would need to be maintained beyond reaching that reduced % for herd immunity. I suspect that relaxing these measures too soon would allow a resurgence of the outbreak because the population would be increasing the needed herd immunity % value. Once herd immunity has been reached, as long as the protective measures are maintained, the population should be relatively safe and the virus should remain suppressed. All of this fits with the “flattening the curve” ideas that specialists talk about. A “second wave” cannot be ruled out, especially in locations where mitigating factors are reduced too early.

Do the above seem reasonable? Are there any other major factors that I am not accounting for?
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Re: Crazy (and not-so-crazy) shit about Covid-19

Postby Steve James on Thu Sep 24, 2020 2:55 pm

Are there any other major factors that I am not accounting for?


Psychology: denial, projection, and transference. Secondly, the number of theories and possibilities will lead to confusion and many people making exactly the wrong decisions.
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Re: Crazy (and not-so-crazy) shit about Covid-19

Postby everything on Thu Sep 24, 2020 2:58 pm

I'm not sure. It seems reasonable from a regular person's logical point of view. Not sure it makes sense from any kind of epidemiological or policy pov. Just don't know.

Some different factors now, 100+ years after that pandemic, are that we have a lot more travel, including in a steel tube with recirculated air, more restaurant patronage, more large indoor events, etc. Not sure if the covidiocy we have now, partly thanks to stupidity easily spread via social media, existed back then. We know social media did not. Not sure we had the widespread, mass wilfully ignorant denial of scientific knowledge and non-conformity to guidance by more knowledgeable people. Certainly the world must have had cults of dumb personalities, though.
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Re: Crazy (and not-so-crazy) shit about Covid-19

Postby Trick on Thu Sep 24, 2020 11:43 pm

everything wrote:I'm not sure. It seems reasonable from a regular person's logical point of view. Not sure it makes sense from any kind of epidemiological or policy pov. Just don't know.

Some different factors now, 100+ years after that pandemic, are that we have a lot more travel, including in a steel tube with recirculated air, more restaurant patronage, more large indoor events, etc. Not sure if the covidiocy we have now, partly thanks to stupidity easily spread via social media, existed back then. We know social media did not. Not sure we had the widespread, mass wilfully ignorant denial of scientific knowledge and non-conformity to guidance by more knowledgeable people. Certainly the world must have had cults of dumb personalities, though.
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Last edited by Trick on Thu Sep 24, 2020 11:45 pm, edited 1 time in total.
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Re: Crazy (and not-so-crazy) shit about Covid-19

Postby Steve James on Fri Sep 25, 2020 4:25 am

Europe appears to be having a second wave at the moment. Check for yourself.

If the pattern holds, we may be due for one too on a similar scale unless...
Aw, cooperation is unlikely.
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Re: Crazy (and not-so-crazy) shit about Covid-19

Postby everything on Fri Sep 25, 2020 7:09 am

im convinced we're collectively too stupid / non-compliant
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Re: Crazy (and not-so-crazy) shit about Covid-19

Postby Trick on Fri Sep 25, 2020 7:20 am

]Europe appears to be having a second wave at the moment. Check for yourself.
yes i read that in the MSM, sweden had two new deaths yesterday or something, the headlines is as if the whole populations about to go under.....meanwhile, i didnt even experience a first wave here in my city in china, everythings back to normal as for moving about in the city...maybe there will be an first wave later ?
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Re: Crazy (and not-so-crazy) shit about Covid-19

Postby Steve James on Fri Sep 25, 2020 8:03 am

Well, I think any solution that was truly collective would work better than having denials and contradictory solutions. I don't think lockdowns would be necessary if people collectively wanted/tried to avoid infecting others. Instead, we've seen people cough on people, spit on fruits and vegetables in stores, and deliberately do things that would spread what they say is a non-existent virus that affects "virtually nobody."

Cases are going up in some countries, like France and the UK. So, what happened last time? Alas, this time the CDC won't be more effective because no one will trust anything that it says. The same goes for the FDA. So, think of it as our zombie apocalypse. You have to take care of yourself, avoid the infected, and watch out for the other humans.
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Re: Crazy (and not-so-crazy) shit about Covid-19

Postby Steve James on Fri Sep 25, 2020 8:19 am

Trick wrote:
]Europe appears to be having a second wave at the moment. Check for yourself.
yes i read that in the MSM, sweden had two new deaths yesterday or something, the headlines is as if the whole populations about to go under.....meanwhile, i didnt even experience a first wave here in my city in china, everythings back to normal as for moving about in the city...maybe there will be an first wave later ?


That illustrates exactly what I wrote about. Anyway, I wasn't referring to Sweden, but looking at that single country doesn't change my point at all.
France and Spain scramble to deal with sharp rise in Covid infections

https://www.theguardian.com/world/2020/ ... strictions

It will be difficult to make people act collectively enough to change the overall outcome. Though, any collective participation in trying to slow the spread of the virus would. People can say the same thing they did five months ago. The economy is affected because of lockdowns, restrictions, and regulations that exist because of the virus.

Cases are going up when kids have to go back to school, when the holiday season begins, when people begin to stay indoors more than outdoors, etc. Sure, let's just send them back and get the economy started again. Then again, three or four months ago, I recall discussing what the toll in lives lost would be if a thousand people died per day for a month. Seemed like a ridiculously large number then. The US lost 400K people in WW2.
Last edited by Steve James on Fri Sep 25, 2020 8:20 am, edited 1 time in total.
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Re: Crazy (and not-so-crazy) shit about Covid-19

Postby meeks on Fri Sep 25, 2020 9:11 am

windwalker wrote:
By applying our theory to the COVID-19 epidemic we found evidence that the hardest hit areas such as New York
City, have likely passed the heterogeneity-modified herd immunity threshold.


Other places that had intermediate exposure, such as e.g. Chicago, while still above the HIT, have their effective reproduction number reduced by a significantly larger factor than predicted by traditional epidemiological models.

This gives a better chance of suppressing the future waves of the epidemic in these locations by less disruptive measures
than those used during the first wave, e.g. by contact tracing, control of potential super-spreading events, etc.

According to our results, a significant suppression of the second wave in both cities is expected even for a rather moderate value of the immunity factor.

https://arxiv.org/pdf/2008.08142.pdf


Significance Statement

This study demonstrates how a wide class of epidemiological models can be adapted for applications to heterogeneous populations in the context of the COVID-19 epidemic. It is shown that a persistent heterogeneity, rather than bursty short-term variations in infection transmission is responsible for self-limiting
epidemic dynamics.

Compact generalizations of the classical results for the herd immunity threshold and the final size
of an epidemic are derived. The degree of persistent heterogeneity is estimated from data on real-life face-to-face contact
networks, and on age variation of susceptibility to COVID-19.

The estimate is further supported by the analysis of the empirical data from the epidemic in NYC and Chicago, as well as in 50 US states.
The results suggest that by the end of the first wave of the epidemic, the hardest-hit areas, such as NYC, have been close to the heterogeneity-modified herd immunity, thereby limiting their vulnerability to a potential second wave of the epidemic.


Ongoing studies suggesting the "herd immunity threshold is much lower than previously thought to be.



https://newsvoice.com/i/5131755
Blood donations show that the US is nowhere near herd immunity
As per a newly published research, of the nearly 1M Americans who donated blood to the Red Cross from Jun 15 to Aug 23 and were tested, only 1.82% had the antibodies. This suggests that a vast majority of Americans have yet to be infected with the virus. The research noted a higher seroprevalence in African-American and Hispanic donors, matching patterns seen in clinical diagnoses of COVID-19.
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Re: Crazy (and not-so-crazy) shit about Covid-19

Postby roger hao on Fri Sep 25, 2020 2:02 pm

I am confused as to -

anti-bodies disappear from those that were infected with Covid

tests on blood donated shows low to no anti-bodies.
and this is a measure of how many have been infected

Any one want to science-splain that?
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Re: Crazy (and not-so-crazy) shit about Covid-19

Postby Peacedog on Fri Sep 25, 2020 4:10 pm

Roger this is the main problem with the disease.

Since people can, apparently, lose the anti-bodies no one is really sure how many people have been infected and herd immunity probably isn't even possible.

Preliminary evidence suggests repeat infections are not as serious as initial infections as well. So there is that upside.

Shut downs have served their primary purpose to slow the rate of infection to the point that hospitals are not overwhelmed. Aside from developing working treatment protocols, and vaccines, no real point exists to any further restriction based efforts. People are just going to have to live with this.

As easily transmitted as the virus appears to be the current reported infection rates of 5%, or less, are just nonsense. Likewise, most of the numbers being reported in Asia are either outright lies or the result of governments refusing to test their populations. If you are in a high risk group, do what you can, but as this looks like an aerosol transmitted virus with a long lifespan on hard surfaces the reality is that quarantines and masks are probably just for show at this point.

Fortunately the overall fatality rate is low. Most of what is going on at this point is simply hysteria and will be viewed as such long term.
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