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In other words, when you recover from covid-19, you are immune to it. In other words, covid-19 is just like every other virus, in this respect. Governments ar

In other words, when you recover from covid-19, you are immune to it. In other words, covid-19 is just like every other virus, in this respect. Governments around the world have reacted with terror to this pandemic, but that doesn't mean the virus is some sort of strange monster. It's extremely infectious, and somewhat more lethal than influenza. That's all. When I first heard about those patients who had recovered from the virus, and yet were still testing positive, it felt like a mistake. I'm glad it's been cleared up.

kleiba 6y ago
In other words, when you recover from covid-19, you are immune to it How does this follow?
- eloff 6y ago
  That's how immunity against pathogens usually works. There are exceptions like the flu which mutates into sufficiently distinct strains that the immune system doesn't (fully) recognize. I'm still oversimplifying here.
  - pbhjpbhj 6y ago
    Well viruses in general, AFAIK, mutate - and that's how we trace their movement through the infected: you sample the virus and look at the mutations eg https://nextstrain.org/ncov https://nextstrain.org/ncov. Do we know for sure that Covid19 in N.Europe isn't sufficiently mutated over that in Australia, say, that secondary infection is possible (even if recovered people's antibodies recognise it somewhat)?
    - eloff 6y ago
      We don't know much for sure. What I've heard from experts in the field, but I don't have sources, is that the type of RNA virus is different from influenza and doesn't mutate as quickly - which is potentially good news for those hoping for a vaccine.
- AnimalMuppet 6y ago
  I think it's an overstatement. When you recover from it, you don't still have it, even if you test positive. That means that at least some of the "got it a second time" reports are false. Are they all false? Don't know. There's hope, but not yet evidence, so far as I know.
  - pbhjpbhj 6y ago
    What evidence are you using to show people have recovered who are still testing positive? What confirms that the positive test is false? Can you provide some sources?
    - Mikeb85 6y ago
      Is this a joke? Literally the article at the top.
      - pbhjpbhj 6y ago
        No, not a joke, you seemed to be talking from a general perspective rather than "in the results in this particular PCR test in South Korea". As if you had generally applicable information. My understanding was there were many different tests being used ... so on what basis are you making that generalised statement. > When you recover from it, you don't still have it, even if you test positive. // A plausible explanation for specific tests doesn't make this a universal truth; so presumably you are relying on more information? Also, there being an explanation for positive tests based on dead virus, doesn't mean all post-infection positive tests are due to dead virus; that's a massive assumption.
      - thro1 6y ago
        He is right, people may be testing positive just because of dead virus fragments, but to say they have fully recovered there must be no virus alive in their bodies - lack of symptoms may suggest it, then having antibodies may guarantee that eventually.. .. assuming the virus can not hide (and be able to leave) where they can't penetrate - like in the eye ? .. and with weak immune system the outcome may be (how?)long undecided as the antibodies are not being able to fight the virus fast enough to finish it definitely?
- jrockway 6y ago
  That doesn't strictly follow. Here is the thought process, though. Typically when you get an infection, your body builds antibodies that can attack the pathogen. The next time the pathogen shows up, your body kills it before you get sick. This immunity doesn't always last for a lifetime, but there is pretty much always some immunity. With COVID-19, early reports showed that this wasn't happening; people got sick, recovered, and then got COVID-19 again. What the news article says is that the test was wrong; when they tested positive the second time, the test was just returning incorrect results (because of limitations of the PCR technique; it's testing for certain RNA, not for the existence of an infectious live virus). So to say that this means you can be immune to SARS-CoV-2 is not strictly correct. What it says is that there is no reason to think that this virus is any different from many of the other viruses that we already know about. (We do know about viruses that you can't be immune to, like HIV. But those viruses explicitly attack the immune system machinery that is supposed to kill them. We have no evidence that SARS-CoV-2 does that.)
  - jtbayly 6y ago
    We also know that immunity to coronaviruses generally declines rapidly. We have no idea how long somebody is immune to Covid-19 when they have recovered.
- rdiddly 6y ago
  It doesn't strictly follow, you're right. But this punches a huge hole in the already kind of surprising/unlikely possibility that we had suddenly just discovered the first (or if I'm wrong, "a very rare") virus that can re-infect the same person with the same strain.
- eschutte2 6y ago
  In at least two ways I can think of. First, these fragments have been inactivated, probably by the immune system, suggesting you have some immunity (obviously, that's not the same as being perfectly immune). Second, given how infectious the virus is, the fact they're not finding genuine positive re-tests strongly suggests some immunity is happening.
- umanwizard 6y ago
  How would you recover at all if your body weren't producing antibodies capable of killing it?
twomoretime 6y ago
>in other words, when you recover from covid-19, you are immune Well, it may appear to be the case so far but afaik that hasn't been rigorously confirmed, and this article doesn't imply immunity to live virus upon reexposure. >but that doesn't mean the virus is some sort of strange monster Except there are dozens of papers being publishes about a range of effects - damage to a multitude of organs, virus fragments found in brains during autopsy, high incidence of clotting/stroke. By many SME accounts it is very much a strange monster. Also recall the documented rapid progression from asymptomatic to dead. >It's extremely infectious, and somewhat more lethal than influenza So one of these numbers (CFR) is about the same, but the R0 is anywhere from 2-4 times larger, and the critical rate appears to much higher than the typical flu. So the response of "terror" isn't totally unwarranted. >When I first heard about those patients who had recovered from the virus, and yet were still testing positive, it felt like a mistake. I'm glad it's been cleared up. Agreed. And another reinfection case occured in an immunocompromised patient. So it's looking like the infection doesn't become chronic or dormant.
acqq 6y ago
> somewhat more lethal than influenza My understanding is that most evidence points to order of magnitude more lethal even when the hospitals aren't overflown. Regarding "testing negative then positive" the experts already expected that there were no real reinfections.
- throwaway894345 6y ago
  > My understanding is that most evidence points to order of magnitude more lethal even when the hospitals aren't overflown. If those mortality estimates were based on the number of positive test cases, then they're very likely overblown. Recent seralogical studies indicate that the number of positive test results are likely a small fraction of the total number of cases, and likely the most severe subset at that. None of this is to say that it's less lethal than influenza, only that the situation is developing rapidly and any given mortality estimate may well be outdated.
  - JoeAltmaier 6y ago
    In any case, we can all agree that regardless of the value of the number, its "way too many fatalities". My family has lost several colleagues/classmates already. This did not happen in other years. This year is very different, and concerning.
    - throwaway894345 6y ago
      I'm terribly sorry for your losses. It's an awful disease, and loss of life is terrible. It is indeed concerning, but if we can understand whether these fatalities are due to high morbidity or "simply" because it is highly contagious, we can make better decisions about treating the disease, setting policy, etc which can all drive down the amount of suffering and death. That's perhaps a small consolation to those who have lost friends and family already. :'(
  - rocha 6y ago
    My understanding is that the current estimated IFR from those studies (NY specially) is between 0.6% and 1.2%. I think flu is around 0.1% (however I am not sure if that is the CFR or the IFR). The second factor to consider is the attack rate, how many people are likely to get infected. For flu is around between 10% to 15% of the total population, while for Covid it is, potentially, larger than 80% (no natural immunity and no vaccines). It is however unlikely that it will reach that level given the current containment and mitigation measures. But if it reaches something like 40% (double of the latest NY estimate), it will mean covid is between 16 to 48 times deadlier than the flu.
cpuguy83 6y ago
Governments are reacting to a seemingly very high infection rate with a (best case from the numbers I've seen) fatality rate 10x higher than the flu and the inadequacy of healthcare systems to shoulder the burden all at once (which has more side effects, including more death).
_bxg1 6y ago
Correction: the virus isn't some sort of strange monster in this particular aspect. Have you seen the reports of blood-clotting problems? Sudden deaths from people who'd shown no symptoms? There's still a lot that's weird about this disease and we have a long way to go before we understand it.
- TheBlight 6y ago
  I'd hold off banking too heavily on anecdotal data. That's how everyone got all worked up about this reinfection story a few weeks ago.
  - jonahbenton 6y ago
    With respect, the story of both governmental and private sector response to COVID has almost universally been not being worked up enough.
    - SpicyLemonZest 6y ago
      Surely the right response to that isn't to always be more worked up.
      - felipemnoa 6y ago
        I think he means plan for the worst, hope for the best.
    - dekhn 6y ago
      From what I can tell, the governor in my state (CA) took an appropriate level of actions at roughly the right time (after realizing that the federal government declined to be useful). We appear to be passing through the first big wave of deaths, and cautiously reopening slowly. It's unclear what additional actions would have changed things (in terms of reducing total # of deaths, or any suffering while sick).
    - fuckknows 6y ago
      Sure, but by getting yourself worked up you're not improving that situation any.
foxyv 6y ago
Reinfection can occur with most viruses when a person is exposed too soon after the primary immune response. It takes a while for someone to develop full immunity after recovery. This happened with H1N1 for patients back in 2008. https://www.virology.ws/2009/12/28/reinfection-with-2009-influenza-h1n1/ https://www.virology.ws/2009/12/28/reinfection-with-2009-inf...
- nfin 6y ago
  Are we talking 2 weeks, a month or 3 months, 6 months+?
- mcbutterbunz 6y ago
  Does viral load also matter? I would imagine that getting hit with a high number of viruses shortly after recovery could cause some issues but I'm just an observer in all of this.
throwaway894345 6y ago
Seems like this would make serology tests a lot more useful. I would really like to know if I've had it so I can know how at-risk I am (and consequently the risk I pose to others).
majormajor 6y ago
> In other words, when you recover from covid-19, you are immune to it. In other words, covid-19 is just like every other virus, in this respect. "Every other virus" doesn't behave the same in this regard. The viruses that cause colds, many of which are also coronaviruses, are pretty adept at hitting people throughout their life. Hopefully it's not an issue here, but it's completely unsurprising that people would want to actually research it instead of just declaring all viruses are the same. The only fools here are the people whose impatience leads them to declare absolutes ahead of times instead of taking preventive measures while the research plays out. https://www.npr.org/sections/goatsandsoda/2020/03/20/819038431/do-you-get-immunity-after-recovering-from-a-case-of-coronavirus https://www.npr.org/sections/goatsandsoda/2020/03/20/8190384... > Researchers do know that reinfection is an issue with the four seasonal coronaviruses that cause about 10 to 30% of common colds.
- deleted 6y ago
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- f38zf5vdt 6y ago
  Yes. It's suspected that immunity is very short lived. > This study provides evidence that re-infections with the same endemic coronavirus are not atypical in a time window shorter than 1 year and that the genetic basis of innate immune response maybe a greater determinant of infection severity than immune memory acquired after a previous infection. http://www.columbia.edu/%7Ejls106/galanti_shaman_ms_supp.pdf http://www.columbia.edu/%7Ejls106/galanti_shaman_ms_supp.pdf Even if you recover, there's not a lot of evidence now as to what the duration of immunity will be. With this spreading through the world at different paces, it means that, as commonly predicted, we will see continuous re-emergence as we do with other cold viruses and influenza.
  - CyanLite2 6y ago
    Recovered patients from SARS-1 had long-term antibodies in good concentrations until about 3 years after the infection. We can expect about the same since both coronaviruses are so similar. Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/
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rocha 6y ago
Note that the immunity is not permanent. The average immunity to the endemic coronaviruses that cause the common cold lasts about a year.
- fat_turdsicle 6y ago
  Could you provide a source? Happen to be studying this topic for a paper I'm writing
  - rocha 6y ago
    Sure: https://www.technologyreview.com/2020/04/27/1000569/how-long-are-people-immune-to-covid-19/ https://www.technologyreview.com/2020/04/27/1000569/how-long...
tptacek 6y ago
In the interpretation of the NYS serostudy most favorable to your argument (assume perfect specificity), with 21% actually infected in NYC proper, based on the death statistics and the population of NYC, C19 appears to be a full order of magnitude more lethal than any recent flu strain. That's more than "somewhat" more lethal. Putting this into perspective: in roughly a single month, we've already doubled the 7-year average annual number of flu deaths. Project those C19 stats out across the whole population, and assume (generously) herd immunity effects at 70% that halt the progression, and you're looking at mortality rate that swamps that of all wars, terrorist attacks, and natural disasters faced by the US for the last 50 years, right? Put differently, unchecked and with that extrapolated fatality rate, we'd be looking at something like 53 years worth of flu deaths at the average annual flu death rate? (Again, I'm just averaging the last 7 years for which we have flu stats; they range between ~12k-45k.) (Happy to have my math corrected).
- TheGallopedHigh 6y ago
  This idea of putting 50 years of any war/ attacks etc is misguided and it’s a wrong use of statistics. A better approach would be to take into account other diseases as you have with its close relative the flu. Others on the list would be other types of diseases. Because all of those dwarfs numbers from wars etc.
  - tptacek 6y ago
    Why is it "misguided and a wrong use of statistics"? It's true that the flu kills far more Americans than the last 50 years of war has. If a new disease emerged that was just the flu in a different form, and we retained the mortality rates both from the flu and that new disease, that alone would be extremely alarming: a new cause of death, displacing none of the other deaths, that exceeds most other causes! Honestly, I think we don't do nearly enough comparisons between disease mortality and other causes of mortality. A "War On Cancer" would have done us far more good than the wars we declared in the 2000s would have.
    - alejohausner 6y ago
Leary 6y ago
There have also been cases where people looked like they've recovered, tested negative, and then became ill again after 2 weeks and tested positive again. I always suspected those were mostly due to false negatives from PCR tests. Probably only a tiny minority of people had not enough immune response for them to become reinfected.
- Marsymars 6y ago
  Given a large enough sample size, you're also going to get people who recover, test negative due to a false negative, then get influenza two weeks later, then test positive due to dead SARS-COV-2 RNA. And various other edge case permutations like that.
staticassertion 6y ago
Virtually all messaging I've seen has been "We lack evidence to say how immunity works" with a dose of "there's some initial evidence suggesting immunity" and "we aren't sure about how long it lasts". It's interesting to read "it's extremely infectious" and "more lethal than influenza" followed by "that's all", not to mention the missing bit about not having a vaccine! If we saw a massive outbreak of influenza things would be extremely different. We have treatments for influenza (tamiflu), we have vaccines, we have understanding, and a large portion of the population that is already immune. The similarities are... they are both viruses. Not sure why anyone would compare the two except to try to explain how different they are.
draw_down 6y ago
Everyone's an armchair virologist all of a sudden in this crisis. Heartening to find we had such expertise just lying around, waiting!
dekhn 6y ago
I don't think we have any reliable evidence of post-recovery immunity at all. I wouldn't expect to have any until we've seen multiple cycles of this virus, and analyzed the data carefully. Press-release-science during an emergency is close to worthless.
- rootusrootus 6y ago
  If you don't have any post-recovery immunity, then how do you ever recover to begin with?
  - dekhn 6y ago
    immunity prevents you from being infected, not from eliminating the virus. People who are cured of AIDS by eliminating HIV aren't then immune.
    - rootusrootus 6y ago
      HIV is a bit of a special case to begin with, since it's attacking the very immune system that would try to kill it. But is anyone clearing the virus on their own? I thought it required extensive retroviral therapy, and even then it isn't actually cleared? Admittedly, I don't really keep up on the status of HIV, maybe something has changed.
      - dekhn 6y ago
        A very small number of people have natural immunity. https://en.wikipedia.org/wiki/Innate_resistance_to_HIV https://en.wikipedia.org/wiki/Innate_resistance_to_HIV I am not sure if anybody gets infected, then clears the virus on their own.
aaomidi 6y ago
Sigh. I was waiting for the "Govts have overreacted" message. This is a ridiculous criticism to have to the response to this pandemic. We NEED to overreact so we don't underreact.
p49k 6y ago
> In other words, when you recover from covid-19, you are immune to it. In other words, covid-19 is just like every other virus, in this respect. That’s not how HSV works. That’s not how hepatitis works.
- mirthflat83 6y ago
  “Just like other coronaviruses” There you go
  - p49k 6y ago
    Even that's not true. 15-30% of the viruses that are attributed to the common cold are coronaviruses, and it's pretty clear that the common cold does not behave in the way OP described.
    - mirthflat83 6y ago
      Do you know about genetic drift/shift/different strains? Moreover, recent literature continues to confirm that you have protective immunity after recovering from covid like any other coronavirus. This is the basis for convalescent plasma therapy
      - p49k 6y ago
        Yes, but you’re drifting from the original point I was arguing against: “all viruses act exactly like the flu, therefore governments overreacted by not immediately assuming it was exactly like the flu” - which has a false premise.
        mirthflat83 6y ago
        No, it’s you who’s drifting away from “Just like other coronaviruses”
- mr_toad 6y ago
  You don’t get re-infected by HSV or chronic hepatitis; you don’t recover in the first place. In the first case the virus hides from the immune system, in the second it never properly overcomes the infection.
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throwawaymanbot 6y ago
I believe they authors said "May" in this. Not that this is 100% the cause. Political tinged screeds are not really appropriate for this issue.
takecarefnd 6y ago
in the article it didn't mention whether when you recover from covid-19, you are immune to it.
thro1 6y ago
> In other words .. What you write is disconnected from the article, immunity was discussed more deeply elsewhere on HN already.
ridgeguy 6y ago
>In other words, when you recover from covid-19, you are immune to it. Probably not. It seems [1] that in humans and animals, there's no long-term immunity arising from infection. [1] https://www.quantamagazine.org/what-can-other-coronaviruses-tell-us-about-sars-cov-2-20200429/ https://www.quantamagazine.org/what-can-other-coronaviruses-...
scotty79 6y ago
> In other words, when you recover from covid-19, you are immune to it. At least for some time. > In other words, covid-19 is just like every other virus, in this respect. Other coronaviruses don't mutate, yet reinfect lots of people and cause some common cold roughly every two years. I think we can expect roughly the same from covid19. Peak every two years until we have a vaccine. Then annual covid19 vaccine shot to refresh the immunity.

kleiba 6y ago

In other words, when you recover from covid-19, you are immune to it How does this follow?

eloff 6y ago
That's how immunity against pathogens usually works. There are exceptions like the flu which mutates into sufficiently distinct strains that the immune system doesn't (fully) recognize. I'm still oversimplifying here.
- pbhjpbhj 6y ago
  Well viruses in general, AFAIK, mutate - and that's how we trace their movement through the infected: you sample the virus and look at the mutations eg https://nextstrain.org/ncov https://nextstrain.org/ncov. Do we know for sure that Covid19 in N.Europe isn't sufficiently mutated over that in Australia, say, that secondary infection is possible (even if recovered people's antibodies recognise it somewhat)?
  - eloff 6y ago
    We don't know much for sure. What I've heard from experts in the field, but I don't have sources, is that the type of RNA virus is different from influenza and doesn't mutate as quickly - which is potentially good news for those hoping for a vaccine.
AnimalMuppet 6y ago
I think it's an overstatement. When you recover from it, you don't still have it, even if you test positive. That means that at least some of the "got it a second time" reports are false. Are they all false? Don't know. There's hope, but not yet evidence, so far as I know.
- pbhjpbhj 6y ago
  What evidence are you using to show people have recovered who are still testing positive? What confirms that the positive test is false? Can you provide some sources?
  - Mikeb85 6y ago
    Is this a joke? Literally the article at the top.
    - pbhjpbhj 6y ago
      No, not a joke, you seemed to be talking from a general perspective rather than "in the results in this particular PCR test in South Korea". As if you had generally applicable information. My understanding was there were many different tests being used ... so on what basis are you making that generalised statement. > When you recover from it, you don't still have it, even if you test positive. // A plausible explanation for specific tests doesn't make this a universal truth; so presumably you are relying on more information? Also, there being an explanation for positive tests based on dead virus, doesn't mean all post-infection positive tests are due to dead virus; that's a massive assumption.
    - thro1 6y ago
      He is right, people may be testing positive just because of dead virus fragments, but to say they have fully recovered there must be no virus alive in their bodies - lack of symptoms may suggest it, then having antibodies may guarantee that eventually.. .. assuming the virus can not hide (and be able to leave) where they can't penetrate - like in the eye ? .. and with weak immune system the outcome may be (how?)long undecided as the antibodies are not being able to fight the virus fast enough to finish it definitely?
jrockway 6y ago
That doesn't strictly follow. Here is the thought process, though. Typically when you get an infection, your body builds antibodies that can attack the pathogen. The next time the pathogen shows up, your body kills it before you get sick. This immunity doesn't always last for a lifetime, but there is pretty much always some immunity. With COVID-19, early reports showed that this wasn't happening; people got sick, recovered, and then got COVID-19 again. What the news article says is that the test was wrong; when they tested positive the second time, the test was just returning incorrect results (because of limitations of the PCR technique; it's testing for certain RNA, not for the existence of an infectious live virus). So to say that this means you can be immune to SARS-CoV-2 is not strictly correct. What it says is that there is no reason to think that this virus is any different from many of the other viruses that we already know about. (We do know about viruses that you can't be immune to, like HIV. But those viruses explicitly attack the immune system machinery that is supposed to kill them. We have no evidence that SARS-CoV-2 does that.)
- jtbayly 6y ago
  We also know that immunity to coronaviruses generally declines rapidly. We have no idea how long somebody is immune to Covid-19 when they have recovered.
rdiddly 6y ago
It doesn't strictly follow, you're right. But this punches a huge hole in the already kind of surprising/unlikely possibility that we had suddenly just discovered the first (or if I'm wrong, "a very rare") virus that can re-infect the same person with the same strain.
eschutte2 6y ago
In at least two ways I can think of. First, these fragments have been inactivated, probably by the immune system, suggesting you have some immunity (obviously, that's not the same as being perfectly immune). Second, given how infectious the virus is, the fact they're not finding genuine positive re-tests strongly suggests some immunity is happening.
umanwizard 6y ago
How would you recover at all if your body weren't producing antibodies capable of killing it?

twomoretime 6y ago

>in other words, when you recover from covid-19, you are immune Well, it may appear to be the case so far but afaik that hasn't been rigorously confirmed, and this article doesn't imply immunity to live virus upon reexposure. >but that doesn't mean the virus is some sort of strange monster Except there are dozens of papers being publishes about a range of effects - damage to a multitude of organs, virus fragments found in brains during autopsy, high incidence of clotting/stroke. By many SME accounts it is very much a strange monster. Also recall the documented rapid progression from asymptomatic to dead. >It's extremely infectious, and somewhat more lethal than influenza So one of these numbers (CFR) is about the same, but the R0 is anywhere from 2-4 times larger, and the critical rate appears to much higher than the typical flu. So the response of "terror" isn't totally unwarranted. >When I first heard about those patients who had recovered from the virus, and yet were still testing positive, it felt like a mistake. I'm glad it's been cleared up. Agreed. And another reinfection case occured in an immunocompromised patient. So it's looking like the infection doesn't become chronic or dormant.

acqq 6y ago

> somewhat more lethal than influenza My understanding is that most evidence points to order of magnitude more lethal even when the hospitals aren't overflown. Regarding "testing negative then positive" the experts already expected that there were no real reinfections.

throwaway894345 6y ago
> My understanding is that most evidence points to order of magnitude more lethal even when the hospitals aren't overflown. If those mortality estimates were based on the number of positive test cases, then they're very likely overblown. Recent seralogical studies indicate that the number of positive test results are likely a small fraction of the total number of cases, and likely the most severe subset at that. None of this is to say that it's less lethal than influenza, only that the situation is developing rapidly and any given mortality estimate may well be outdated.
- JoeAltmaier 6y ago
  In any case, we can all agree that regardless of the value of the number, its "way too many fatalities". My family has lost several colleagues/classmates already. This did not happen in other years. This year is very different, and concerning.
  - throwaway894345 6y ago
    I'm terribly sorry for your losses. It's an awful disease, and loss of life is terrible. It is indeed concerning, but if we can understand whether these fatalities are due to high morbidity or "simply" because it is highly contagious, we can make better decisions about treating the disease, setting policy, etc which can all drive down the amount of suffering and death. That's perhaps a small consolation to those who have lost friends and family already. :'(
- rocha 6y ago
  My understanding is that the current estimated IFR from those studies (NY specially) is between 0.6% and 1.2%. I think flu is around 0.1% (however I am not sure if that is the CFR or the IFR). The second factor to consider is the attack rate, how many people are likely to get infected. For flu is around between 10% to 15% of the total population, while for Covid it is, potentially, larger than 80% (no natural immunity and no vaccines). It is however unlikely that it will reach that level given the current containment and mitigation measures. But if it reaches something like 40% (double of the latest NY estimate), it will mean covid is between 16 to 48 times deadlier than the flu.

cpuguy83 6y ago

Governments are reacting to a seemingly very high infection rate with a (best case from the numbers I've seen) fatality rate 10x higher than the flu and the inadequacy of healthcare systems to shoulder the burden all at once (which has more side effects, including more death).

_bxg1 6y ago

Correction: the virus isn't some sort of strange monster in this particular aspect. Have you seen the reports of blood-clotting problems? Sudden deaths from people who'd shown no symptoms? There's still a lot that's weird about this disease and we have a long way to go before we understand it.

TheBlight 6y ago
I'd hold off banking too heavily on anecdotal data. That's how everyone got all worked up about this reinfection story a few weeks ago.
- jonahbenton 6y ago
  With respect, the story of both governmental and private sector response to COVID has almost universally been not being worked up enough.
  - SpicyLemonZest 6y ago
    Surely the right response to that isn't to always be more worked up.
    - felipemnoa 6y ago
      I think he means plan for the worst, hope for the best.
  - dekhn 6y ago
    From what I can tell, the governor in my state (CA) took an appropriate level of actions at roughly the right time (after realizing that the federal government declined to be useful). We appear to be passing through the first big wave of deaths, and cautiously reopening slowly. It's unclear what additional actions would have changed things (in terms of reducing total # of deaths, or any suffering while sick).
  - fuckknows 6y ago
    Sure, but by getting yourself worked up you're not improving that situation any.

foxyv 6y ago

Reinfection can occur with most viruses when a person is exposed too soon after the primary immune response. It takes a while for someone to develop full immunity after recovery. This happened with H1N1 for patients back in 2008. https://www.virology.ws/2009/12/28/reinfection-with-2009-influenza-h1n1/ https://www.virology.ws/2009/12/28/reinfection-with-2009-inf...

nfin 6y ago
Are we talking 2 weeks, a month or 3 months, 6 months+?
mcbutterbunz 6y ago
Does viral load also matter? I would imagine that getting hit with a high number of viruses shortly after recovery could cause some issues but I'm just an observer in all of this.

throwaway894345 6y ago

Seems like this would make serology tests a lot more useful. I would really like to know if I've had it so I can know how at-risk I am (and consequently the risk I pose to others).

majormajor 6y ago

> In other words, when you recover from covid-19, you are immune to it. In other words, covid-19 is just like every other virus, in this respect. "Every other virus" doesn't behave the same in this regard. The viruses that cause colds, many of which are also coronaviruses, are pretty adept at hitting people throughout their life. Hopefully it's not an issue here, but it's completely unsurprising that people would want to actually research it instead of just declaring all viruses are the same. The only fools here are the people whose impatience leads them to declare absolutes ahead of times instead of taking preventive measures while the research plays out. https://www.npr.org/sections/goatsandsoda/2020/03/20/819038431/do-you-get-immunity-after-recovering-from-a-case-of-coronavirus https://www.npr.org/sections/goatsandsoda/2020/03/20/8190384... > Researchers do know that reinfection is an issue with the four seasonal coronaviruses that cause about 10 to 30% of common colds.

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f38zf5vdt 6y ago
Yes. It's suspected that immunity is very short lived. > This study provides evidence that re-infections with the same endemic coronavirus are not atypical in a time window shorter than 1 year and that the genetic basis of innate immune response maybe a greater determinant of infection severity than immune memory acquired after a previous infection. http://www.columbia.edu/%7Ejls106/galanti_shaman_ms_supp.pdf http://www.columbia.edu/%7Ejls106/galanti_shaman_ms_supp.pdf Even if you recover, there's not a lot of evidence now as to what the duration of immunity will be. With this spreading through the world at different paces, it means that, as commonly predicted, we will see continuous re-emergence as we do with other cold viruses and influenza.
- CyanLite2 6y ago
  Recovered patients from SARS-1 had long-term antibodies in good concentrations until about 3 years after the infection. We can expect about the same since both coronaviruses are so similar. Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/

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rocha 6y ago

Note that the immunity is not permanent. The average immunity to the endemic coronaviruses that cause the common cold lasts about a year.

fat_turdsicle 6y ago
Could you provide a source? Happen to be studying this topic for a paper I'm writing
- rocha 6y ago
  Sure: https://www.technologyreview.com/2020/04/27/1000569/how-long-are-people-immune-to-covid-19/ https://www.technologyreview.com/2020/04/27/1000569/how-long...

tptacek 6y ago

In the interpretation of the NYS serostudy most favorable to your argument (assume perfect specificity), with 21% actually infected in NYC proper, based on the death statistics and the population of NYC, C19 appears to be a full order of magnitude more lethal than any recent flu strain. That's more than "somewhat" more lethal. Putting this into perspective: in roughly a single month, we've already doubled the 7-year average annual number of flu deaths. Project those C19 stats out across the whole population, and assume (generously) herd immunity effects at 70% that halt the progression, and you're looking at mortality rate that swamps that of all wars, terrorist attacks, and natural disasters faced by the US for the last 50 years, right? Put differently, unchecked and with that extrapolated fatality rate, we'd be looking at something like 53 years worth of flu deaths at the average annual flu death rate? (Again, I'm just averaging the last 7 years for which we have flu stats; they range between ~12k-45k.) (Happy to have my math corrected).

TheGallopedHigh 6y ago
This idea of putting 50 years of any war/ attacks etc is misguided and it’s a wrong use of statistics. A better approach would be to take into account other diseases as you have with its close relative the flu. Others on the list would be other types of diseases. Because all of those dwarfs numbers from wars etc.
- tptacek 6y ago
  Why is it "misguided and a wrong use of statistics"? It's true that the flu kills far more Americans than the last 50 years of war has. If a new disease emerged that was just the flu in a different form, and we retained the mortality rates both from the flu and that new disease, that alone would be extremely alarming: a new cause of death, displacing none of the other deaths, that exceeds most other causes! Honestly, I think we don't do nearly enough comparisons between disease mortality and other causes of mortality. A "War On Cancer" would have done us far more good than the wars we declared in the 2000s would have.
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Leary 6y ago

There have also been cases where people looked like they've recovered, tested negative, and then became ill again after 2 weeks and tested positive again. I always suspected those were mostly due to false negatives from PCR tests. Probably only a tiny minority of people had not enough immune response for them to become reinfected.

Marsymars 6y ago
Given a large enough sample size, you're also going to get people who recover, test negative due to a false negative, then get influenza two weeks later, then test positive due to dead SARS-COV-2 RNA. And various other edge case permutations like that.

staticassertion 6y ago

Virtually all messaging I've seen has been "We lack evidence to say how immunity works" with a dose of "there's some initial evidence suggesting immunity" and "we aren't sure about how long it lasts". It's interesting to read "it's extremely infectious" and "more lethal than influenza" followed by "that's all", not to mention the missing bit about not having a vaccine! If we saw a massive outbreak of influenza things would be extremely different. We have treatments for influenza (tamiflu), we have vaccines, we have understanding, and a large portion of the population that is already immune. The similarities are... they are both viruses. Not sure why anyone would compare the two except to try to explain how different they are.

draw_down 6y ago

Everyone's an armchair virologist all of a sudden in this crisis. Heartening to find we had such expertise just lying around, waiting!

dekhn 6y ago

I don't think we have any reliable evidence of post-recovery immunity at all. I wouldn't expect to have any until we've seen multiple cycles of this virus, and analyzed the data carefully. Press-release-science during an emergency is close to worthless.

rootusrootus 6y ago
If you don't have any post-recovery immunity, then how do you ever recover to begin with?
- dekhn 6y ago
  immunity prevents you from being infected, not from eliminating the virus. People who are cured of AIDS by eliminating HIV aren't then immune.
  - rootusrootus 6y ago
    HIV is a bit of a special case to begin with, since it's attacking the very immune system that would try to kill it. But is anyone clearing the virus on their own? I thought it required extensive retroviral therapy, and even then it isn't actually cleared? Admittedly, I don't really keep up on the status of HIV, maybe something has changed.
    - dekhn 6y ago
      A very small number of people have natural immunity. https://en.wikipedia.org/wiki/Innate_resistance_to_HIV https://en.wikipedia.org/wiki/Innate_resistance_to_HIV I am not sure if anybody gets infected, then clears the virus on their own.

aaomidi 6y ago

Sigh. I was waiting for the "Govts have overreacted" message. This is a ridiculous criticism to have to the response to this pandemic. We NEED to overreact so we don't underreact.

p49k 6y ago

> In other words, when you recover from covid-19, you are immune to it. In other words, covid-19 is just like every other virus, in this respect. That’s not how HSV works. That’s not how hepatitis works.

mirthflat83 6y ago
“Just like other coronaviruses” There you go
- p49k 6y ago
  Even that's not true. 15-30% of the viruses that are attributed to the common cold are coronaviruses, and it's pretty clear that the common cold does not behave in the way OP described.
  - mirthflat83 6y ago
    Do you know about genetic drift/shift/different strains? Moreover, recent literature continues to confirm that you have protective immunity after recovering from covid like any other coronavirus. This is the basis for convalescent plasma therapy
    - p49k 6y ago
      Yes, but you’re drifting from the original point I was arguing against: “all viruses act exactly like the flu, therefore governments overreacted by not immediately assuming it was exactly like the flu” - which has a false premise.
      - mirthflat83 6y ago
        No, it’s you who’s drifting away from “Just like other coronaviruses”
mr_toad 6y ago
You don’t get re-infected by HSV or chronic hepatitis; you don’t recover in the first place. In the first case the virus hides from the immune system, in the second it never properly overcomes the infection.

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throwawaymanbot 6y ago

I believe they authors said "May" in this. Not that this is 100% the cause. Political tinged screeds are not really appropriate for this issue.

takecarefnd 6y ago

in the article it didn't mention whether when you recover from covid-19, you are immune to it.

thro1 6y ago

> In other words .. What you write is disconnected from the article, immunity was discussed more deeply elsewhere on HN already.

ridgeguy 6y ago

>In other words, when you recover from covid-19, you are immune to it. Probably not. It seems [1] that in humans and animals, there's no long-term immunity arising from infection. [1] https://www.quantamagazine.org/what-can-other-coronaviruses-tell-us-about-sars-cov-2-20200429/ https://www.quantamagazine.org/what-can-other-coronaviruses-...

scotty79 6y ago

> In other words, when you recover from covid-19, you are immune to it. At least for some time. > In other words, covid-19 is just like every other virus, in this respect. Other coronaviruses don't mutate, yet reinfect lots of people and cause some common cold roughly every two years. I think we can expect roughly the same from covid19. Peak every two years until we have a vaccine. Then annual covid19 vaccine shot to refresh the immunity.