8 ms·

This is good news because it suggests that immunity for SARS-CoV2 isn't worse than that for other coronaviruses (e.g. those causing the common cold), even for t

This is good news because it suggests that immunity for SARS-CoV2 isn't worse than that for other coronaviruses (e.g. those causing the common cold), even for those individuals who didn't become so sick they had to be hospitalised. In a nutshell, you can't catch it again right away after having recovered.

acqq 6y ago
No honest scientist would say what you wrote as your “nutshell.” Specifically, T cell response is not equivalent at all to “you can’t catch it.” Still all scenarios are possible: 1) you can still catch it, and still get more sick 2) you can catch it, and be less sick 3) you can be “sterilizingly immune” meaning that you won’t get sick and won’t be able to transmit to somebody else. But which of those will be by majority the study just didn’t investigate. In immunology no answer is “yes” or “no” but the range. The range is different between different people, and we can conclude what the typical ranges are, if there’s enough data collected. But the ranges are still unknown at the moment. The same reason (a need to find the ranges) is why you can’t make a vaccine candidate and be sure how it will work, unless you run big and long enough trials. And that’s why that takes time. Here’s what this study figured out, quoting from the article: “The size of T cell response differed between individuals, being considerably (50%) higher in people who had experienced symptomatic disease at the time of infection six months previously. Further research will be needed to determine the significance of this finding.” As you see, again some range, but also not concluding what you claim.
- Robotbeat 6y ago
  We have been running a "natural" trial on millions of people. From that, we can already tell that reinfection, although possible, is very rare.
  - acqq 6y ago
    > From that, we can already tell that reinfection, although possible, is very rare. No. From the current papers, we just know that the reinfection where people have had their virus sequenced in both first and second infection is very rare. The problem is technological. Up to now there are around 50 million confirmed cases in the world but probably less than 100 thousand sequencings performed, and only a few sequencings by those who had strong enough symptoms twice and had the chance to have sequencing twice. Without sequencing one just can’t prove that some case is an actual reinfection. All other cases are just “possible” (i.e. unprovable) reinfections and nobody can claim anything worthy of a scientific paper about them.
  - macintux 6y ago
    Can we really? Infection itself is still somewhat uncommon, thanks to the global reaction to the pandemic. I don't doubt that reinfection will be rare, at least over the span of a few months, but to my mind that would seem unproven given how hard we're (generally) working to keep people from being infected in the first place.
    - krona 6y ago
      In many countries, healthcare workers are exposed (to varying degrees) on a daily basis.
      - Symmetry 6y ago
        Good point. I'd hope they'd receive regular testing as well.
        kaitai 6y ago
        Unfortunately, your hope is unfounded. My spouse is a physician and when coughing (acute bronchitis) could not get a test without job consequences (being forced to take 10 days off and reschedule all patients regardless of the outcome of the test). There has been an exposure in a neighboring ward through a fellow healthcare worker and tests are not being made available broadly. Remember, in the US healthcare workers generally have to go through insurance to get approved for tests, etc., even though they work in healthcare -- they're not at this time provided anything more than the general public in terms of diagnostics. (At least spouse gets free masks at work, haha...)
      - rusk 6y ago
        Yes ... and they are getting reinfected. The fatality rate among medics is quite high relative to general population
        krona 6y ago
        The fatality rate among medics is quite high relative to general population 'Quite high' could mean anything, but if you're implying 'higher than' then that isn't supported by the statistics I've seen in a dozen countries.
  - Symmetry 6y ago
    I'm not sure we can rule out the idea that reinfection after 6 months is common but almost always asymptomatic in people with healthy immune systems. There was that British common cold coronavirus challenge trial where most subjects could be reinfected after 1 year, confirmed by PCR, but none of them developed symptoms.
    - acqq 6y ago
      Which could mean that such asymptomatic people could still infect somebody vulnerable, if they shed enough virus at some point of their reinfection. The open question is, again, what will be the percentage of such cases.
      - SomeoneFromCA 6y ago
        Unfortunately there are several taboos on many forums, regarding discussion Covid. For ex.: Covid reinfections, lab origins of covid etc.
        acqq 6y ago
        SARS-CoV-2 has not been created in the lab. The genome looks completely different than such.
        anoncake 6y ago
        How do you identify a lab-created virus?
        SomeoneFromCA 6y ago
        Of course there is no way. I think people need to start relaxing. Trump has lost, so stop being afraid talking about the lab origins of Covid.
        SomeoneFromCA 6y ago
        Yeah, exactly what I was talking about. There is no way to say this just by looking at the genome, all you can do is to say that is not very probable, and that would still be a dubious claim. There is a plenty of gnome manipulations that leave no trace. Having said that, lab origin does not neccesarily mean genetic manipulation. Serial passage through animals (say, minks) will leave no trace of genetic engineering, but may make the virus contagius to humans (minks and humans have similar ACE2 receptor). Or just poorly handled sample from the would do.
  - kaitai 6y ago
    There is a temporal component here. As an ancestor commenter said, "you can't catch it again right away" (emphasis added). We do not know (because we cannot know) if reinfection is possible after two years, for instance, because we have not had the virus for two years yet.
    - rusk 6y ago
      Don’t forget there are lifestyle factors that can effect your immune response. You’ll typically fight off a cold except for that one time when it catches you tired, or stressed ...
  - SomeoneFromCA 6y ago
    Do you know how academic, narrow and unpractically stiff are criteria for a proof of reinfection? You need to have the viral genome sequenced TWO times, and both times it must be a slightly DIFFERENT virus. In that context "very rare" is not a useful term.
Tylerian 6y ago
> In a nutshell, you can't catch it again right away after having recovered. If that's the case, out of curiousity why there has been numerous reported cases of people that catched covid again after already recovering from it? Edit: So... after reading the article I'm not sure this is the case for all people as this research has been done only on a group of asymptomatic & low/mild response people. IMHO for a sentence like that to be valid, it should be demonstrated on the other part of the population, those that have a high immune response against the virus and end up in a critical state from it.
- timr 6y ago
  "If that's the case, out of curiousity why there has been numerous reported cases of people that catched covid again after already recovering from it?" There have been many, many news articles that speculate about this, but to date, I'm aware of two papers that document re-infections. Both papers isolated and sequenced the viruses involved, and both papers documented re-infection with significantly mutated variants of the same virus.
  - thamer 6y ago
    Yes, here is an example of a paper that mentions a re-infection with significant genomic differences between the two samples: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30764-7/fulltext https://www.thelancet.com/journals/laninf/article/PIIS1473-3...
skrebbel 6y ago
I'm an absolute layman, but "no worse than the common cold" doesn't sound too great to me since I've always been told you can keep getting the cold over and over again. What am I missing?
- rhino369 6y ago
  There are a lot of different common cold viruses, so catching one doesn't give you immunity for the rest.
  - skrebbel 6y ago
    (username checks out) Ah! I knew that this was true for the flu, but I always thought there was just a single Common Cold that you could get over and over again. Thanks!
    - rhino369 6y ago
      I think you can get most of them again, but not for a few years.
    - goodcanadian 6y ago
      If you look at the Wikipedia article, you will find more detailed information, but the common cold is caused primarily by rhinoviruses. However, some are also coronaviruses and even influenza viruses. There are hundreds of viruses that cause "the cold." https://en.m.wikipedia.org/wiki/Common_cold https://en.m.wikipedia.org/wiki/Common_cold
- BjoernKW 6y ago
  There are several coronaviruses that cause what's commonly known as "the cold". If you catch one and recover you're likely to be immune against infections from the same viral strain for some time. For SARS-CoV2 and the COVID-19 disease it causes this means that even without the - quite likely - availability of a vaccine over time natural immunity will build up within individuals and the population as a whole, which has the potential of both making the resulting disease less severe and future waves spreading less. If most individuals who contract the virus during the next few months can't get sick anymore and can't spread the virus anymore for the about 6 months those individuals are taken out of the equation, which leaves less individuals for the virus to spread to in the next wave.
jmcqk6 6y ago
>In a nutshell, you can't catch it again right away after having recovered. "Can't" is too extreme. "Very unlikely" is much more accurate.
- adrianb 6y ago
  Extrapolating from other coronaviruses, it's probably that you CAN catch it again but it's "very unlikely" to produce serious consequences after the first time. So basically only first time you will experience more serious symptoms like a fever, the subsequent infections would be trivial common cold. We'll see.
  - ljf 6y ago
    I think we should consider it to be as yet unproven - a person I know through my wife caught it in April (and tested positive them) and wasn't that ill. They just got very ill again in the last week and tested positive again. Might be totally a-typical or it could just be that we've not seen that many people actually have the chance to catch it twice yet.
    - mam2 6y ago
      Positive with what ? I head PCR stay positive a long time

acqq 6y ago

No honest scientist would say what you wrote as your “nutshell.” Specifically, T cell response is not equivalent at all to “you can’t catch it.” Still all scenarios are possible: 1) you can still catch it, and still get more sick 2) you can catch it, and be less sick 3) you can be “sterilizingly immune” meaning that you won’t get sick and won’t be able to transmit to somebody else. But which of those will be by majority the study just didn’t investigate. In immunology no answer is “yes” or “no” but the range. The range is different between different people, and we can conclude what the typical ranges are, if there’s enough data collected. But the ranges are still unknown at the moment. The same reason (a need to find the ranges) is why you can’t make a vaccine candidate and be sure how it will work, unless you run big and long enough trials. And that’s why that takes time. Here’s what this study figured out, quoting from the article: “The size of T cell response differed between individuals, being considerably (50%) higher in people who had experienced symptomatic disease at the time of infection six months previously. Further research will be needed to determine the significance of this finding.” As you see, again some range, but also not concluding what you claim.

Robotbeat 6y ago
We have been running a "natural" trial on millions of people. From that, we can already tell that reinfection, although possible, is very rare.
- acqq 6y ago
  > From that, we can already tell that reinfection, although possible, is very rare. No. From the current papers, we just know that the reinfection where people have had their virus sequenced in both first and second infection is very rare. The problem is technological. Up to now there are around 50 million confirmed cases in the world but probably less than 100 thousand sequencings performed, and only a few sequencings by those who had strong enough symptoms twice and had the chance to have sequencing twice. Without sequencing one just can’t prove that some case is an actual reinfection. All other cases are just “possible” (i.e. unprovable) reinfections and nobody can claim anything worthy of a scientific paper about them.
- macintux 6y ago
  Can we really? Infection itself is still somewhat uncommon, thanks to the global reaction to the pandemic. I don't doubt that reinfection will be rare, at least over the span of a few months, but to my mind that would seem unproven given how hard we're (generally) working to keep people from being infected in the first place.
  - krona 6y ago
    In many countries, healthcare workers are exposed (to varying degrees) on a daily basis.
    - Symmetry 6y ago
      Good point. I'd hope they'd receive regular testing as well.
      - kaitai 6y ago
        Unfortunately, your hope is unfounded. My spouse is a physician and when coughing (acute bronchitis) could not get a test without job consequences (being forced to take 10 days off and reschedule all patients regardless of the outcome of the test). There has been an exposure in a neighboring ward through a fellow healthcare worker and tests are not being made available broadly. Remember, in the US healthcare workers generally have to go through insurance to get approved for tests, etc., even though they work in healthcare -- they're not at this time provided anything more than the general public in terms of diagnostics. (At least spouse gets free masks at work, haha...)
    - rusk 6y ago
      Yes ... and they are getting reinfected. The fatality rate among medics is quite high relative to general population
      - krona 6y ago
        The fatality rate among medics is quite high relative to general population 'Quite high' could mean anything, but if you're implying 'higher than' then that isn't supported by the statistics I've seen in a dozen countries.
- Symmetry 6y ago
  I'm not sure we can rule out the idea that reinfection after 6 months is common but almost always asymptomatic in people with healthy immune systems. There was that British common cold coronavirus challenge trial where most subjects could be reinfected after 1 year, confirmed by PCR, but none of them developed symptoms.
  - acqq 6y ago
    Which could mean that such asymptomatic people could still infect somebody vulnerable, if they shed enough virus at some point of their reinfection. The open question is, again, what will be the percentage of such cases.
    - SomeoneFromCA 6y ago
      Unfortunately there are several taboos on many forums, regarding discussion Covid. For ex.: Covid reinfections, lab origins of covid etc.
      - acqq 6y ago
        SARS-CoV-2 has not been created in the lab. The genome looks completely different than such.
        anoncake 6y ago
        How do you identify a lab-created virus?
        SomeoneFromCA 6y ago
        Of course there is no way. I think people need to start relaxing. Trump has lost, so stop being afraid talking about the lab origins of Covid.
        SomeoneFromCA 6y ago
        Yeah, exactly what I was talking about. There is no way to say this just by looking at the genome, all you can do is to say that is not very probable, and that would still be a dubious claim. There is a plenty of gnome manipulations that leave no trace. Having said that, lab origin does not neccesarily mean genetic manipulation. Serial passage through animals (say, minks) will leave no trace of genetic engineering, but may make the virus contagius to humans (minks and humans have similar ACE2 receptor). Or just poorly handled sample from the would do.
- kaitai 6y ago
  There is a temporal component here. As an ancestor commenter said, "you can't catch it again right away" (emphasis added). We do not know (because we cannot know) if reinfection is possible after two years, for instance, because we have not had the virus for two years yet.
  - rusk 6y ago
    Don’t forget there are lifestyle factors that can effect your immune response. You’ll typically fight off a cold except for that one time when it catches you tired, or stressed ...
- SomeoneFromCA 6y ago
  Do you know how academic, narrow and unpractically stiff are criteria for a proof of reinfection? You need to have the viral genome sequenced TWO times, and both times it must be a slightly DIFFERENT virus. In that context "very rare" is not a useful term.

Tylerian 6y ago

> In a nutshell, you can't catch it again right away after having recovered. If that's the case, out of curiousity why there has been numerous reported cases of people that catched covid again after already recovering from it? Edit: So... after reading the article I'm not sure this is the case for all people as this research has been done only on a group of asymptomatic & low/mild response people. IMHO for a sentence like that to be valid, it should be demonstrated on the other part of the population, those that have a high immune response against the virus and end up in a critical state from it.

timr 6y ago
"If that's the case, out of curiousity why there has been numerous reported cases of people that catched covid again after already recovering from it?" There have been many, many news articles that speculate about this, but to date, I'm aware of two papers that document re-infections. Both papers isolated and sequenced the viruses involved, and both papers documented re-infection with significantly mutated variants of the same virus.
- thamer 6y ago
  Yes, here is an example of a paper that mentions a re-infection with significant genomic differences between the two samples: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30764-7/fulltext https://www.thelancet.com/journals/laninf/article/PIIS1473-3...

skrebbel 6y ago

I'm an absolute layman, but "no worse than the common cold" doesn't sound too great to me since I've always been told you can keep getting the cold over and over again. What am I missing?

rhino369 6y ago
There are a lot of different common cold viruses, so catching one doesn't give you immunity for the rest.
- skrebbel 6y ago
  (username checks out) Ah! I knew that this was true for the flu, but I always thought there was just a single Common Cold that you could get over and over again. Thanks!
  - rhino369 6y ago
    I think you can get most of them again, but not for a few years.
  - goodcanadian 6y ago
    If you look at the Wikipedia article, you will find more detailed information, but the common cold is caused primarily by rhinoviruses. However, some are also coronaviruses and even influenza viruses. There are hundreds of viruses that cause "the cold." https://en.m.wikipedia.org/wiki/Common_cold https://en.m.wikipedia.org/wiki/Common_cold
BjoernKW 6y ago
There are several coronaviruses that cause what's commonly known as "the cold". If you catch one and recover you're likely to be immune against infections from the same viral strain for some time. For SARS-CoV2 and the COVID-19 disease it causes this means that even without the - quite likely - availability of a vaccine over time natural immunity will build up within individuals and the population as a whole, which has the potential of both making the resulting disease less severe and future waves spreading less. If most individuals who contract the virus during the next few months can't get sick anymore and can't spread the virus anymore for the about 6 months those individuals are taken out of the equation, which leaves less individuals for the virus to spread to in the next wave.

jmcqk6 6y ago

>In a nutshell, you can't catch it again right away after having recovered. "Can't" is too extreme. "Very unlikely" is much more accurate.

adrianb 6y ago
Extrapolating from other coronaviruses, it's probably that you CAN catch it again but it's "very unlikely" to produce serious consequences after the first time. So basically only first time you will experience more serious symptoms like a fever, the subsequent infections would be trivial common cold. We'll see.
- ljf 6y ago
  I think we should consider it to be as yet unproven - a person I know through my wife caught it in April (and tested positive them) and wasn't that ill. They just got very ill again in the last week and tested positive again. Might be totally a-typical or it could just be that we've not seen that many people actually have the chance to catch it twice yet.
  - mam2 6y ago
    Positive with what ? I head PCR stay positive a long time