Cont: The One Covid-19 Science and Medicine Thread Part 2

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Skeptic Ginger said:
Because we don't know yet if people can get reinfected.
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Has there been a single verified case of it happening?

Even if we don't know with metaphysical certainty, it's a pretty darn good bet, and furthermore, even if reinfection is possible, is it likely? If a prior infection provides no resistance whatsoever, then we're all doomed anyway because a vaccine will be impossible.


Because the risks here are not only on one side of the equation. Humanity cannot remain on permanent lockdown forever. At some point life has to go back to normal.

Personally as a betting man, if I knew for certain that I had the antibodies, I would be much less worried about getting reinfected (just as I don't worry about getting measles or other diseases that I've been vaccinated for).
 
Puppycow said:
Has there been a single verified case of it happening?
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No. But it's too soon to know if anyone who has recovered has been re-exposed.

Puppycow said:
Even if we don't know with metaphysical certainty, it's a pretty darn good bet, and furthermore, even if reinfection is possible, is it likely? If a prior infection provides no resistance whatsoever, then we're all doomed anyway because a vaccine will be impossible.


Because the risks here are not only on one side of the equation. Humanity cannot remain on permanent lockdown forever. At some point life has to go back to normal.

Personally as a betting man, if I knew for certain that I had the antibodies, I would be much less worried about getting reinfected (just as I don't worry about getting measles or other diseases that I've been vaccinated for).
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As an infectious disease practitioner for the last 30 years, I would not take that bet.

If you get the chance to try it out, let us know. :p
 
Puppycow said:
Compare them with a control group.
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China has contracted with Canada for their phase 3 trials for this very reason. Since rates of natural exposure in China are way down, there really isn't a good control group. Canada has a high enough rate still that some exposure can be expected in the vaccinated and unvaccinated groups.
 
Skeptic Ginger said:
China has contracted with Canada for their phase 3 trials for this very reason. Since rates of natural exposure in China are way down, there really isn't a good control group. Canada has a high enough rate still that some exposure can be expected in the vaccinated and unvaccinated groups.
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Since there are already over 1 million recovered patients in the USA alone, a trial should be relatively easy to conduct.

Recruit X number of recovered patients and an equal number of people who haven't had it yet to be a control group.

Exactly how large X needs to be should be a matter for the statistics people to figure out. But the larger, the better.

For this trial you don't need to administer any drugs or placebos, you just need people to agree to be tested every few weeks or so.

Make the control group as close as possible demographically and geographically as the study group. Over time, presumably, some fraction of the control group will test positive. If nobody from the study group, or a significantly smaller fraction than the control group tests positive, you know that they have some immunity or at least resistance to reinfection.
 
Puppycow said:
Since there are already over 1 million recovered patients in the USA alone, a trial should be relatively easy to conduct.

Recruit X number of recovered patients and an equal number of people who haven't had it yet to be a control group.

Exactly how large X needs to be should be a matter for the statistics people to figure out. But the larger, the better.

For this trial you don't need to administer any drugs or placebos, you just need people to agree to be tested every few weeks or so.

Make the control group as close as possible demographically and geographically as the study group. Over time, presumably, some fraction of the control group will test positive. If nobody from the study group, or a significantly smaller fraction than the control group tests positive, you know that they have some immunity or at least resistance to reinfection.
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While I see this is all (misguided) speculation, do you want to be the person that went through a COVID infection who now lets their guard down just to answer your question sooner rather than later?

It's not necessary. We know who people are that have recovered. If/when one turns up with a reinfection, we'll know.

Until then, there's nothing researchers need to do... except wait. That is the ethical thing to do.
 
Skeptic Ginger said:
While I see this is all (misguided) speculation, do you want to be the person that went through a COVID infection who now lets their guard down just to answer your question sooner rather than later?

It's not necessary. We know who people are that have recovered. If/when one turns up with a reinfection, we'll know.

Until then, there's nothing researchers need to do... except wait. That is the ethical thing to do.
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I disagree. This is not the same as a "challenge" experiment where you intentionally expose someone to the virus. If I had been though it, unless I had a particularly severe case, I would in fact happily volunteer. If I was one of the asymptomatic ones, I would think it would be a risk worth taking. Mind you, I'm not suggesting anyone go out of their way to expose themselves again, just live your normal life.

In your scenario, how long do we have to wait and how will we know when we know? With over a million recovered patients (over 6 million worldwide) wouldn't we see at least a handful of reinfections by now, if it were possible to be reinfected?
 
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Myriad said:
The role of antibody tests in the statistics reporting is confusing to me right now. MA has been reporting the results of thousands of antibody tests a week, but there's nothing in the public guidelines, the instructions about who should get tested or what to do if you want to get tested, that even mentions the possibility of getting an antibody test. Maybe they are being used only for prevalence studies.

The strange thing, though, is that positive antibody tests are being classified as "probable cases" and as these are discovered, they're being reported as equivalent to new cases in the day to day numbers. In other words, each day there are "newly reported confirmed cases" (111, yesterday) from PCR testing and "newly reported probable cases" (25, yesterday) from antibody testing, and those are added together as 136 "newly reported cases today." And that's the number that data aggregator sites are using for the number of "new cases" each day in MA. Those time-shifted numbers could become very misleading as time goes on.
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I'd love to see your source for this, Myriad. Very interesting!

Victoria jumped from about 90 cases on Sunday to 191 today.


portlandatheist said:
CNN reports Regeneron starts Phase 3 trial of Covid antibody drug

This is the first I've heard about it. Even if this treatment does pan out, I'm curious about how quickly they could scale up production to make it widely available. I hope this turns out.
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Thanks!

I noted these bits:

"Regeneron said last month that its antibody cocktail will be tested in four separate study populations:
people who are hospitalized with Covid-19;
people who have symptoms for the disease, but are not hospitalized;
people who are healthy but are at a high risk for getting sick; and
healthy people who have come into close contact with a person who is sick."

But not testing those who haven't been exposed? Or is that unethical?

And is this aimed to be a cure, not a vaccine?


Also from CNN:

"Regeneron is not the first company to get a Covid-19 antibody therapy into human trials. Eli Lilly and AbCellera started testing their antibody treatment in humans June 1."




Puppycow said:
Personally, I would like to know whether I have immunity or not, just so I don't have to worry anymore.
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That there goes for me too.

I had my blood taken for an antibody test 2 weeks ago, but haven't got the results back yet.



marting said:
At this point there should be a large enough set of folks that have been tested in the past for antibodies and were positive to provide preliminary data on the degree of immunity, if any, a prior exposure produces since people continue to get infected.

This is more doable in places that had serological surveys earlier as well as have been experiencing increasing new cases. California in particular.

So where is this data?
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See Myriad's post above?

Maybe now there is more antibody testing there will be more controlled results of known cases after-the-fact.

i.e. I mean that, like me, there were people who got the virus when tests weren't being done, and then later can get an antibody test.

Known knowns, known unknowns etc. Puppycow is an unknown known if he's been tested. I'm still an unknown unknown, officially.
 
Orphia Nay said:
Puppycow is an unknown known if he's been tested. I'm still an unknown unknown, officially.
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To clarify: I have never been tested. I live in Japan, and testing here is not very widespread. They do about 6K tests per day, and while I and may family all had cold-like symptoms back in February, we didn't get tested at the time and haven't been tested since. It's unlikely that we had it though, judging from population studies that have been done since. Only about 0.1% of the people are testing positive for antibodies as of June. Another study by SoftBank found 0.43% of the people they tested had the antibodies.
 
Puppycow said:
Has there been a single verified case of it happening?

Even if we don't know with metaphysical certainty, it's a pretty darn good bet, and furthermore, even if reinfection is possible, is it likely? If a prior infection provides no resistance whatsoever, then we're all doomed anyway because a vaccine will be impossible.
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I think it's reasonably safe to say infection and consequent antibodies will offer protection for at least several months. The shortest protective period I can think of is norovirus, which is 3-4 months. We know humans build short term resistance to other coronaviruses, so it's not illogical to think we will to Covid.
 
TellyKNeasuss said:
I didn't quite grasp what this treatment is. Are they creating synthetic antibodies? Or replicating actual antibodies taken from people who have been infected? Or are they creating something that will stimulate the creation of specific antibodies if administered to a person?
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Recombinant antibody technology allows for the production of the entire human antibody library and these are rapidly screened to identify clonal antibodies that can be manufactured to high volumes and purified for therapeutic use. Or the DNA isolated from the B cells of infected individuals can be isolated and developed into clonal antibodies. The last bit is not what they are doing, this would be a vaccine.
 
Orphia Nay said:
I'd love to see your source for this, Myriad. Very interesting!
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For Massachusetts, it's spelled out pretty clearly in the daily "dashboard" document, on the initial summary pages. Note that the document itself is clear about distinguishing between PCR nasal swab tests (they use the term "molecular" tests) and antibody tests. It's when a data aggregator extracts one single number from all those results that the meaning gets a little garbled.

Here's Sunday's Massachusetts daily dashboard that I was referring to: https://www.mass.gov/doc/covid-19-dashboard-july-5-2020/download

An archive of past MA daily dashboards is here: https://www.mass.gov/info-details/archive-of-covid-19-cases-in-massachusetts

And, just in the last two days, the formatting of the MA dashboard has changed, so that it now emphasizes only the confirmed (molecular/PCR tested) cases on the summary page, and describes the antibody test figures separately on a later page, and no longer sums their respective "new" case figures together. I guess I wasn't the only one complaining that that could be misleading.

Here's Monday's Massachusetts daily dashboard, with the changed format: https://www.mass.gov/doc/covid-19-dashboard-july-6-2020/download

Most or all U.S. states have some sort of similar daily dashboard. You can usually find them by googling "[name of state] covid dashboard" and it might take a few clicks from there.
 
There's enough data now to establish that there is some degree of immunity after recovering. What there isn't is enough data to establish that there is immunity beyond a short timeframe.

Looking at the USA data, by 4/27/20, there were 1,000,000 cases with PCR testing. By 6/7/20 that had doubled to 2,000,000. By 7/6/20 it had reached 3,000,000.

The reasonable assumption that 500,000 of the initial set were milder and not hospitalized and recovered at home within a 1 week period leaves a pretty big group of people that were going about their business in June. Further I assume these people behaved similarly to the population as a whole. This is a conservative assumption since I expect a significant percentage figured that they had already got it, were immune, and even if they got it again it wouldn't be serious.

So how does that work out?

If we take the estimate that for every 20 persons infected only 1 gets PCR tested positive.

That would mean in June roughly 1.5% more of the US population was infected.

Let's start with the null assumption that there is no immunity.

1.5% of the 500,000 previously recovered is 7,500 people newly re-infected folks. If one out of 20 of these then got tested that should be around 375 PCR positives on people that had recovered it there was no short term (beyond a few weeks) immunity.

Assuming that case tracking isn't completely broken in the USA, if that was occurring all sorts of alarm bells would be ringing. But the data is there, it just isn't published which probably means that it is a much smaller number than 375.

So the evidence is that there is at least a significant degree of short term immunity. But this tells us little about whether such immunity lasts more than a few months. That remains the critical question. Over time we will learn more about how long and how much of immunity lasts.
 
marting said:
There's enough data now to establish that there is some degree of immunity after recovering. What there isn't is enough data to establish that there is immunity beyond a short timeframe.

Looking at the USA data, by 4/27/20, there were 1,000,000 cases with PCR testing. By 6/7/20 that had doubled to 2,000,000. By 7/6/20 it had reached 3,000,000.

The reasonable assumption that 500,000 of the initial set were milder and not hospitalized and recovered at home within a 1 week period leaves a pretty big group of people that were going about their business in June. Further I assume these people behaved similarly to the population as a whole. This is a conservative assumption since I expect a significant percentage figured that they had already got it, were immune, and even if they got it again it wouldn't be serious.

So how does that work out?

If we take the estimate that for every 20 persons infected only 1 gets PCR tested positive.

That would mean in June roughly 1.5% more of the US population was infected.

Let's start with the null assumption that there is no immunity.

1.5% of the 500,000 previously recovered is 7,500 people newly re-infected folks. If one out of 20 of these then got tested that should be around 375 PCR positives on people that had recovered it there was no short term (beyond a few weeks) immunity.

Assuming that case tracking isn't completely broken in the USA, if that was occurring all sorts of alarm bells would be ringing. But the data is there, it just isn't published which probably means that it is a much smaller number than 375.

So the evidence is that there is at least a significant degree of short term immunity. But this tells us little about whether such immunity lasts more than a few months. That remains the critical question. Over time we will learn more about how long and how much of immunity lasts.
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Good! :)

Quibbles:
- just how “significant” the degree of short term immunity is is important: nearly everyone has it, but there are big variations in duration, protective power etc (maybe oldies have much shorter, weaker immunity?)?
- in some places in the US case tracing is likely robust, in others not so much; for sure how good it’s been, in any place, has surely varied a lot over the last ~four months.
 
Puppycow said:
Has there been a single verified case of it happening?

Even if we don't know with metaphysical certainty, it's a pretty darn good bet, and furthermore, even if reinfection is possible, is it likely? If a prior infection provides no resistance whatsoever, then we're all doomed anyway because a vaccine will be impossible.


Because the risks here are not only on one side of the equation. Humanity cannot remain on permanent lockdown forever. At some point life has to go back to normal.

Personally as a betting man, if I knew for certain that I had the antibodies, I would be much less worried about getting reinfected (just as I don't worry about getting measles or other diseases that I've been vaccinated for).
Click to expand...

This is the kind of optimistic "I'm sure it will be fine" mindset that got most of the world in the situation we're all in now.
 
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