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Author Topic: Coronavirus / COVID-19  (Read 34936 times)
Gimfain
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Reply #875 on: July 06, 2020, 03:08:13 AM

Read an article based on an extremely limited chinese study of 37 who had fallen ill and recovered, plus 37 positive patients that never developed symptoms. Within 8 weeks 40% of asymptomatic patients and 13% of those with symptoms had antibodies levels that could no longer be detected.
Clinical and immunological assessment of asymptomatic SARS-CoV-2 infections

It says nothing about immunity but it sounds like its going to be hard to achieve any sort of herd immunity over a longer period of time through infection or vaccines unless there is something scientists are missing.

When you ask for a miracle, you have to be prepared to believe in it or you'll miss it when it comes
Chimpy
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Reply #876 on: July 06, 2020, 07:33:17 AM

There have also been a few studies that surmise that T-Cell response and not antibodies may have the greater impact on this virus.

It is still too early to tell what any immunity is, and how long it lasts.

Remember folks, we are talking about a disease that has only been recognized as being a particular virus for barely over 6 months.

I know 6 months is an eternity in 2020 and all, but it will be literally years before we know if immunity is even really possible.

Though I am of the opinion that having survived the Spanish Flu makes your chances of survival way higher than normal. I have seen several stories now of people 102-106 who survived having Covid.

'Reality' is the only word in the language that should always be used in quotes.
slog
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Reply #877 on: July 06, 2020, 08:30:18 AM

At this point, how good are the antibody tests?  Are the results reliable enough to make it worthwhile to get one?

"Die of flaming ass cancer you schmuck. No really, die."

.
eldaec
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Reply #878 on: July 06, 2020, 08:39:57 AM

The tests that process samples in a lab are supposed to be accurate.

But nobody has a fucking clue whether it means anything.

"People will not assume that what they read on the internet is trustworthy or that it carries any particular ≠assurance or accuracy" - Lord Leveson
"Hyperbole is a cancer" - Lakov Sanite
Tebonas
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Reply #879 on: July 06, 2020, 09:09:38 AM

So this weekend I heard that the US still doesn't to pool testing because there aren't rules in place for that yet after months of Covid. I'm not surprised anymore you don't get shit done. An idiot president really brings the whole house down.
Khaldun
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Reply #880 on: July 06, 2020, 09:12:57 AM

Which is not just the test but the other uncertainties as just mentioned by Gimfain.

We don't even have a great understanding just yet of what's happened with people who've recovered and are having no further symptoms (or why some people continue to experience symptoms for weeks or months).

----------

The US federal government is driven exclusively by Trump's understanding of what he needs for his re-election, and he's decided that what he needs is to pretend coronavirus doesn't exist. So yeah, there will be no national rules, procedures or infrastructures until January 2021 at the earliest.
Khaldun
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Reply #881 on: July 06, 2020, 09:28:54 AM

Speaking of this, despite the severity of the Spanish outbreak earlier this year, a new study shows that only 5% of the Spanish population seem to have evidence of an antibody response to covid-19. There wasn't an appreciably higher indication of antibody formation in places that had been covid-19 hotspots.

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31483-5/fulltext

So we're really facing a bad scenario here.

1. It may be that people who don't get sick from covid-19 aren't being protected primarily by antibody formation but simply because they're not very vulnerable for other reasons that don't lend themselves to population-level immunization (whether via vaccine or exposure). Meaning covid-19 may well become endemic and continue to attack vulnerable populations for years to come.

2. Even if the people working on vaccines feel like they've got a working version, it may be hard to measure its efficacy and it may not last for very long.

3. People who were exposed and were not affected/were asymptomatic may be infected more severely on re-exposure.

4. If the virus goes fully endemic, it may have further opportunities to mutate and adapt to human beings as a vector. On the other hand, maybe coronaviruses aren't built for us--that big RNA genome that they all have may be because they have evolved to bats, who have very unusual immune systems.

5. The upshot is that we had probably start planning for a future where covid-19 joins the family of recurrent scourges of human societies. I think this means that a lot of resources should also be going right now into therapeutic strategies.
Trippy
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Reply #882 on: July 06, 2020, 02:32:26 PM

Read an article based on an extremely limited chinese study of 37 who had fallen ill and recovered, plus 37 positive patients that never developed symptoms. Within 8 weeks 40% of asymptomatic patients and 13% of those with symptoms had antibodies levels that could no longer be detected.
Clinical and immunological assessment of asymptomatic SARS-CoV-2 infections

It says nothing about immunity but it sounds like its going to be hard to achieve any sort of herd immunity over a longer period of time through infection or vaccines unless there is something scientists are missing.
There have also been a few studies that surmise that T-Cell response and not antibodies may have the greater impact on this virus.

It is still too early to tell what any immunity is, and how long it lasts.

Remember folks, we are talking about a disease that has only been recognized as being a particular virus for barely over 6 months.

I know 6 months is an eternity in 2020 and all, but it will be literally years before we know if immunity is even really possible.
Immunity is possible but it is still unknown how long it might last either if "naturally" acquired or with any of the many upcoming vaccines being developed. It may also depend on the severity of the case. I.e. those with no or mild symptoms may not be immune as long as those with worse symptoms.
Trippy
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Reply #883 on: July 06, 2020, 03:02:44 PM

Speaking of this, despite the severity of the Spanish outbreak earlier this year, a new study shows that only 5% of the Spanish population seem to have evidence of an antibody response to covid-19. There wasn't an appreciably higher indication of antibody formation in places that had been covid-19 hotspots.

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31483-5/fulltext

So we're really facing a bad scenario here.

1. It may be that people who don't get sick from covid-19 aren't being protected primarily by antibody formation but simply because they're not very vulnerable for other reasons that don't lend themselves to population-level immunization (whether via vaccine or exposure). Meaning covid-19 may well become endemic and continue to attack vulnerable populations for years to come.

2. Even if the people working on vaccines feel like they've got a working version, it may be hard to measure its efficacy and it may not last for very long.

3. People who were exposed and were not affected/were asymptomatic may be infected more severely on re-exposure.

4. If the virus goes fully endemic, it may have further opportunities to mutate and adapt to human beings as a vector. On the other hand, maybe coronaviruses aren't built for us--that big RNA genome that they all have may be because they have evolved to bats, who have very unusual immune systems.

5. The upshot is that we had probably start planning for a future where covid-19 joins the family of recurrent scourges of human societies. I think this means that a lot of resources should also be going right now into therapeutic strategies.
You are presuming too much from this one study. Even though Spain was hard hit by the virus we're still only talking about 0.6% of the population with confirmed cases (298,869 confirmed / 46,755,070 population). The fact that this sampling showed that the actual infected % was about 10x the confirmed cases is useful information but you can't assume that achieving population-wide immunity is therefore impossible because only 5% have had it now or that that 5% number was much larger at some point but most of those infected no longer have detectable antibodies.

If you look at the seroprevalence numbers of smaller populations that have been heavily infected that have been tested the numbers are much much higher. E.g. in the Bergamo region in Italy it's estimated that 57% have been infected. Roughly 25% of NYC may have been infected as well.
Trippy
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Reply #884 on: July 06, 2020, 05:25:48 PM

At this point, how good are the antibody tests?  Are the results reliable enough to make it worthwhile to get one?
It depends. When the test is performed (i.e. how many days post-initial infection) and which test is used can both affect the results. And there's probably others things as well that can affect things (e.g. tests via blood drawn in a hospital might be more accurate than a pin-prick blood sample test).

The FDA has been independently testing antibody tests. You can peruse the results here:

https://www.fda.gov/medical-devices/emergency-situations-medical-devices/eua-authorized-serology-test-performance

If you read the "About this page" stuff it discusses how population "prevalence" affects the actual false positive and false negative performance of tests. They don't really explain why that is but this Scientific American article does:

https://www.scientificamerican.com/article/coronavirus-antibody-tests-have-a-mathematical-pitfall/

Essentially the less prevalent the virus is in a population the more likely a positive test is a false positive. The same is true with negative tests but reversed (and to a much lesser extent). I.e. the less prevalent the virus is in a population the more likely a negative test is a true negative.

So basically you want a test with both a high PPV (Positive Predictive Value) and high NPV (Negative Predictive Value) at whatever prevalence % you believe your area is at right now. Ideally both would be at 100% (estimated) but note that these tests also have a confidence interval so you also want one with a very narrow CI.

As for when the test is performed, according to this Cochrane review:

Summary: https://www.cochrane.org/news/new-cochrane-review-assesses-how-accurate-antibody-tests-are-detecting-covid-19
Study: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD013652/full

the tests in the studies they reviewed were most accurate between 15 and 35 days after symptoms first began. Sooner than that and the tests were less accurate and there wasn't enough data to analyze the accuracy after 35 days.
Khaldun
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Reply #885 on: July 06, 2020, 07:38:38 PM

Are there working vaccines that induce T-cell responses rather than being built off of antibody responses? (If it turns out that the Spanish results are because most of the recovered/exposed people were protected by T-cell rather than antibody responses?)
Trippy
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Reply #886 on: July 06, 2020, 07:57:22 PM

The Oxford one does in pigs. Does that count? https://www.biorxiv.org/content/10.1101/2020.06.20.159715v1
Khaldun
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Reply #887 on: July 07, 2020, 11:40:16 AM

Guess we'll find out!

Interesting piece in the WaPo by a guy in one of the vaccine trials, by the way, just describing the experience.
Gimfain
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Reply #888 on: July 09, 2020, 03:32:21 AM

2 months and my sense of smell is still mostly gone apart from noticing strong perfume or horrid stench. Sense of taste have gradually returned but last days it suddenly disappeared which coincided with grass allergy. I still haven't developed bat sonar to compensate.

When you ask for a miracle, you have to be prepared to believe in it or you'll miss it when it comes
eldaec
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Reply #889 on: July 09, 2020, 09:05:34 AM

Fucking comics lying to us.

"People will not assume that what they read on the internet is trustworthy or that it carries any particular ≠assurance or accuracy" - Lord Leveson
"Hyperbole is a cancer" - Lakov Sanite
Gimfain
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Reply #890 on: July 09, 2020, 11:30:03 AM

Read some statistics on the 30-day mortality for covid-19 patients at ICU. It was 34% for patients that first got treated in march, it dropped down to 19% in april and in may it was down to a mere 4%.

When you ask for a miracle, you have to be prepared to believe in it or you'll miss it when it comes
Trippy
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Reply #891 on: July 09, 2020, 11:54:50 AM

Is that age-adjusted?
slog
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Reply #892 on: July 09, 2020, 12:23:31 PM

Read some statistics on the 30-day mortality for covid-19 patients at ICU. It was 34% for patients that first got treated in march, it dropped down to 19% in april and in may it was down to a mere 4%.

That's really good news.  Hopefully they can continue that downward trend.

"Die of flaming ass cancer you schmuck. No really, die."

.
Gimfain
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Reply #893 on: July 09, 2020, 12:55:37 PM

Is that age-adjusted?

No. its based on total ICU patients. Its important to know that extremely few old people get intensive care treatment due to extremely high mortality. For ages 80+ that received ICU treatment, women had 88% mortality, men 66%.

When you ask for a miracle, you have to be prepared to believe in it or you'll miss it when it comes
Khaldun
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Reply #894 on: July 09, 2020, 06:21:20 PM

This reminds me of the theory among medical historians that the 1918-1920 pandemic faded partly because physicians got much better at treating it and because with the end of the war had the resources to treat it in a focused way.

The way out on this may not be a vaccine--it may just be a far better clinical understanding of what's happening when someone gets acutely ill from covid-19 and a far better strategy for treating it. The worst thing the Chinese government may have done is pass on an idea that covid-19 was closely akin to MERS and SARS in clinical terms, such that everyone got ready to treat a severe respiratory disease that presented like a pneumonia, when in fact they were facing a disease that caused respiratory symptoms for completely different reasons.
Khaldun
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Reply #895 on: July 11, 2020, 03:58:46 PM

Depressing but on the money interview with Larry Brilliant on where we're at in July 2020.

https://www.wired.com/story/larry-brilliant-on-how-well-are-we-fighting-covid-19/
Samwise
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Reply #896 on: July 11, 2020, 04:31:10 PM

Depressing but on the money interview with Larry Brilliant on where we're at in July 2020.

https://www.wired.com/story/larry-brilliant-on-how-well-are-we-fighting-covid-19/

That was good.  I guess the ray of sunshine is that the experts seem optimistic about us having a vaccine eventually, and by that point odds are we'll have a new president who will have begun to unfuck the country.

"I have not actually recommended many games, and I'll go on the record here saying my track record is probably best in the industry." - schild
BobtheSomething
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Reply #897 on: July 12, 2020, 02:56:40 PM

I read somewhere that one of the lingering effects of ďasymptomaticĒ Covid 19 is erectile dysfunction.  I donít know if thatís true, but I bet spreading the word will help with mask compliance.
jgsugden
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Reply #898 on: July 12, 2020, 03:01:17 PM

Read some statistics on the 30-day mortality for covid-19 patients at ICU. It was 34% for patients that first got treated in march, it dropped down to 19% in april and in may it was down to a mere 4%.
One statistic set I'd like to find is: How long are people in various age groups hospitalized, in ICU, and ventilated - and what is the attached fatality rates for each of those classifications.  I'm hearing a lot of stories about 8 weeks in the hospital (which could be one reason the stats for May admissions might be low - many have not died, yet).

Edit to include the limited I have found: https://www.medrxiv.org/content/10.1101/2020.04.30.20084780v3.full.pdf
« Last Edit: July 13, 2020, 09:20:29 AM by jgsugden »

2020 will be the year I gave up all hope.
Khaldun
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Reply #899 on: July 12, 2020, 05:48:35 PM

I've actually read that there have been a few cases of dangerous sustained erections from microclotting in the penis--the kind of thing that threatens your future sexual functioning.
HaemishM
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Reply #900 on: July 12, 2020, 07:53:39 PM

Yay, Covid wants to blow my dick off.

Fuck everything about 2020.

Gimfain
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Reply #901 on: July 15, 2020, 01:38:32 AM

Read some statistics on the 30-day mortality for covid-19 patients at ICU. It was 34% for patients that first got treated in march, it dropped down to 19% in april and in may it was down to a mere 4%.
Yeah, 4% for may was actually wrong, caused by bug in the system, it was too good to be true. The actual number for may was 19% so not an actual improvement over time.

A university study over flu patients at a hospital (sahlgrenska universitetssjukhuset) found that for 435 laboratory verified flu patients during 2016-2017 that 114 of those cases got the flu at hospital. Its patients that were hospitalized for other illnesses and got the flu symptoms 48 hours or more after they were initially hospitalized.

For covid-19 they found that 10300 people working at healthcare had contracted covid-19 in mid may, which is about half of the confirmed cases in sweden. Sweden did have limited testing availability at the time but during a crisis the most important people ends up ill.

When you ask for a miracle, you have to be prepared to believe in it or you'll miss it when it comes
Khaldun
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Reply #902 on: July 15, 2020, 07:14:48 PM

I stupidly didn't bookmark it, but there were a couple of Twitter accounts I follow reporting today a new study that adds to the evidence that viral load is a key differentiator between serious and mild cases of covid-19--and that while masks don't prevent you from getting an asymptomatic or mild case of covid-19, they do apparently prevent exposure at levels that may be associated with severe or fatal cases. I'll try to track down the study link.
MahrinSkel
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When she crossed over, she was just a ship. But when she came back... she was bullshit!


Reply #903 on: July 15, 2020, 11:44:40 PM

It's fundamental virology, so I'll take your word for it. Exponential curves that start from 1 and from 1^5th are very different things.

--Dave

Edit: And I just realized that should be 10 and 10^5th, because one to the fifth power is still 1.
« Last Edit: July 16, 2020, 08:55:51 AM by MahrinSkel »

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calapine
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Reply #904 on: July 16, 2020, 03:30:12 AM

I stupidly didn't bookmark it, but there were a couple of Twitter accounts I follow reporting today a new study that adds to the evidence that viral load is a key differentiator between serious and mild cases of covid-19--and that while masks don't prevent you from getting an asymptomatic or mild case of covid-19, they do apparently prevent exposure at levels that may be associated with severe or fatal cases. I'll try to track down the study link.

Nots sure if it's the study you refer to, but the conclusion is similar:

Quote
Surgical mask partition reduces the risk of non-contact transmission in a golden Syrian hamster model for Coronavirus Disease 2019 (COVID-19)


Surgical mask partition for challenged index hamsters significantly reduced transmission to only 16.7% (2/12, P=0.019) of exposed naÔve hamsters. Unlike the severe COVID-19 manifestations of challenged hamsters, infected naÔve hamsters had lower clinical scores, milder histopathological changes, and lower viral nucleocapsid antigen expression in respiratory tract tissues.

https://academic.oup.com/cid/article/doi/10.1093/cid/ciaa644/5848814


That aside: I want to see this naive hamsters with surgical masks.  Heart

Restoration is a perfectly valid school of magic!
Khaldun
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Reply #905 on: July 16, 2020, 10:24:44 AM

Presumably there's some sophisticated hipster hamsters with stylish respirators being used as a control.

Chimpy
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Reply #906 on: July 16, 2020, 12:42:11 PM

It says "partition" so they probably just put a fabric wall between the hamsters.

'Reality' is the only word in the language that should always be used in quotes.
Trippy
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Reply #907 on: July 16, 2020, 01:27:09 PM

That's correct. They were not wearing hamster-sized and shaped masks.
HaemishM
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Reply #908 on: July 16, 2020, 01:31:15 PM

Well that just seems like a waste of a good opportunity.

Sky
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Reply #909 on: July 16, 2020, 02:50:34 PM

They tried it but half of the hamsters freaked out and started screaming about freedom.

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