Author Topic: Coronavirus  (Read 685743 times)

StubbleJumper

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Re: Coronavirus
« Reply #7730 on: September 28, 2020, 07:30:44 PM »
[
The most pertinent is that the weekly hospitalizations have dropped by 75% (8.2 on July 18 to 2.3 on Sep 19th per 100,000).
That is US in hospitalizations is about same in first week of March!
I still could not figure out how to include the image inside the post, but I attached the image.
https://gis.cdc.gov/grasp/COVIDNet/COVID19_3.html

No, that's fair.  I was hasty in my response and I have struck it out.


SJ


Cigarbutt

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Re: Coronavirus
« Reply #7731 on: September 28, 2020, 07:58:58 PM »
...
To the question how many are still vulnerable, it is relevant how many are vulnerable with zero antibodies.
The most pertinent is that the weekly hospitalizations have dropped by 75% (8.2 on July 18 to 2.3 on Sep 19th per 100,000).
That is US in hospitalizations is about same in first week of March!
I still could not figure out how to include the image inside the post, but I attached the image.
https://gis.cdc.gov/grasp/COVIDNet/COVID19_3.html
Why is it that herd immunity would be the only factor?
The household transmission rates are interesting. If herd immunity is the factor, how do you explain the following:
-These and similar studies show that transmission rates for COVID in the household are way higher than for MERS or SARS, does that mean that herd immunity had been reached for those previous viral episodes?
-Proximity seems to play a role (spouses vs others etc), so why not consider increased in-house basic precautions and basic distancing as relevant and important co-factors?
-The study mentioned that self-quarantine (behavior) made a huge difference in transmission outcomes, irrespective of any theoretical herd, natural or innate immunity, so how does that fit in the mono-factor immunity theory?
-Many places in the world have reached antibody levels higher than 30, 40, 50 or even 60%. If cell-mediated immunity is such a critical variable, why doesn't it prevent antibody levels from reaching such high levels?
Look at the following. The study has significant weaknesses but it was made in a relatively controlled environment where herd immunity took a while to kick in:
https://www.medrxiv.org/content/10.1101/2020.09.16.20194787v1
Personal note: my area recorded one of the highest prevalence of disease last spring. And now the same area shows a significant rise in cases, although, for a variety of reasons and including also a partial level (IMO) of herd immunity, this "second" wave should result in less morbidity and mortality. But despite this higher herd immunity obtained due to previous institutional weakness and basic competence issues, it seems that my area will do worse (because of persistent and widespread community spread) than most parts of Canada who, it seems, made a conscious step to not bet on the herd.

Investor20

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Re: Coronavirus
« Reply #7732 on: September 28, 2020, 09:25:28 PM »
...
To the question how many are still vulnerable, it is relevant how many are vulnerable with zero antibodies.
The most pertinent is that the weekly hospitalizations have dropped by 75% (8.2 on July 18 to 2.3 on Sep 19th per 100,000).
That is US in hospitalizations is about same in first week of March!
I still could not figure out how to include the image inside the post, but I attached the image.
https://gis.cdc.gov/grasp/COVIDNet/COVID19_3.html
Why is it that herd immunity would be the only factor?
The household transmission rates are interesting. If herd immunity is the factor, how do you explain the following:
-These and similar studies show that transmission rates for COVID in the household are way higher than for MERS or SARS, does that mean that herd immunity had been reached for those previous viral episodes?
-Proximity seems to play a role (spouses vs others etc), so why not consider increased in-house basic precautions and basic distancing as relevant and important co-factors?
-The study mentioned that self-quarantine (behavior) made a huge difference in transmission outcomes, irrespective of any theoretical herd, natural or innate immunity, so how does that fit in the mono-factor immunity theory?
-Many places in the world have reached antibody levels higher than 30, 40, 50 or even 60%. If cell-mediated immunity is such a critical variable, why doesn't it prevent antibody levels from reaching such high levels?
Look at the following. The study has significant weaknesses but it was made in a relatively controlled environment where herd immunity took a while to kick in:
https://www.medrxiv.org/content/10.1101/2020.09.16.20194787v1
Personal note: my area recorded one of the highest prevalence of disease last spring. And now the same area shows a significant rise in cases, although, for a variety of reasons and including also a partial level (IMO) of herd immunity, this "second" wave should result in less morbidity and mortality. But despite this higher herd immunity obtained due to previous institutional weakness and basic competence issues, it seems that my area will do worse (because of persistent and widespread community spread) than most parts of Canada who, it seems, made a conscious step to not bet on the herd.

" The seroprevalence fell in July and August due to antibody waning. " states the article you posted.  The problem with seroprevalence studies are that antibodies are lasting only few months as seen in above study.

Bill Gates said, we probably will need two doses of vaccines and quoting Bill Gates regarding side effects "“some of that is not dramatic where it’s just super painful". Now if only antibodies confer immunity and antibodies after vaccination last only few months, we are in trouble right?

I always thought the vaccine development is also based on non-antibody immunity, but that applies to prior infected too.  The article you posted makes that clear.  The number of infected  and immunity is much more than the antibody study results.

We also see repeatedly cases fall once the seroprevalence reaches 20-30%. Sweden had 14% antibodies in July. Yet we dont see any second wave in Sweden. To take the seroprevalance of 14%in July and say Sweden has long way to go when we can also see the peak deaths in Sweden is in April!
We can agree July is after April?
https://www.thelocal.se/20200723/14-of-antibody-tests-positive-in-sweden
14% of coronavirus antibody tests positive in Sweden in July
https://www.worldometers.info/coronavirus/country/sweden/

The other corroborating evidence is the one I posted before, spouse secondary attack rate below 50%.
« Last Edit: September 28, 2020, 09:29:54 PM by Investor20 »

Cigarbutt

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Re: Coronavirus
« Reply #7733 on: Today at 04:52:03 AM »
...
 The number of infected  and immunity is much more than the antibody study results.
We also see repeatedly cases fall once the seroprevalence reaches 20-30%.
https://www.thelocal.se/20200723/14-of-antibody-tests-positive-in-sweden
...
i agree with you directionally. It's the extent we can rely on natural immunity that is risky (IMO).
Have you looked at the dialysis seroprevalence study that Spekulatius submitted? The study has limitations but the limitations are listed and discussed. It is a source of some powerful information. Relevant for this discussion:
-There was a remarkable variation in seroprevalence by state in the sampled participants, with early pandemic hotspots such as New York (33·6%, 95% CI 31·7–35·6), Louisiana (17·6%, 10·8–28·7), and Illinois (17·5%, 15·2–20·2) recording substantially higher seroprevalence than their respective neighbouring states of Pennsylvania (6·4%, 4·7–8·8), Arkansas (1·9%, 1·0–3·5), and Missouri (1·9%, 0·9–3·8).
-The study also estimated substantially higher seroprevalence in residents of predominantly Hispanic (11·3%, 95% CI 9·8–12·9), non-Hispanic Black (13·9%, 12·1–16·0), and Hispanic and Black (16·3%, 14·3–18·5) neighbourhoods compared with predominantly non-Hispanic white neighbourhoods (4·8%, 4·1–5·5), when standardised to the US adult population.

There are large segments in the population who have risk factors (including relative lower levels of innate or cell-mediated immunity) and who happen to live in crowded conditions with people living in the same household who can't simultaneously work at home and "protect". The remarkable variation in prevalence of antibody-mediated immunity and the heterogeneity of the population makes the concept of a unique % number of antibody levels relatively risky, in its application.

mattee2264

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Re: Coronavirus
« Reply #7734 on: Today at 07:43:47 AM »

 The other thing that gets forgotten is that a coronavirus vaccine may need to be as much as 70-80% effective before we can stop social distancing. So preliminary versions of the vaccine may not reduce the risk to an acceptable level and in the meantime social and economic costs continue to mount. So I think to some degree we do need to build up some natural immunity and learn to live with the virus while shielding as much as possible those for whom the virus could be deadly.