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The entire theory of the solution to coronavirus hinges on an assumption that it will eventually pass once a critical mass of people have been infected and deve

by wycy 7y ago

The entire theory of the solution to coronavirus hinges on an assumption that it will eventually pass once a critical mass of people have been infected and developed immunity. The handful of stories like this trickling out might imply that the immunity assumption could be incorrect. What would be the ramifications of this? Could corona just bounce around the population for the rest of time, putting everyone at a high percentage chance of dying or requiring hospitalization multiple times a year? Could it be the kind of thing that comes back as a novel form every year like the flu? Could we be seeing covid-20, covid-21, etc ad infinitum, with high mortality/low life expectancy just being a new reality of life? EDIT: If this were the case, and immunity is very shortlived after the virus is gone, maybe it could be contained through giving everyone an extremely frequent regimen of vaccines until this particular strain is out of circulation?

chickenpotpie 7y ago
Is it at all possible that we become progressively more immune with each incidence or that we can only be infected N times? If either of these things are true our strategy will still work.
dooglius 7y ago
It's not a boolean whether people become immune or not--maybe some small portion of the population have issues developing immunity and the rest are fine?
- __blockcipher__ 7y ago
  My reasoning is the same, but rather than it being binary, it’s a gradient. So after recovery I might be able to ward off 80% of exposure events that would infect a non-immune person. But given enough exposures or just really bad luck, I could still get infected again. That being said generally in these cases the infection resolves way sooner due to the same mechanism that leads to immunity: immune “memory cells” which wait dormant, ready to start production of immune cels when exposed to the characteristic antigens
__blockcipher__ 7y ago
I’m unaware of _any_ illness where some measure of immunity is not developed. I find it incredibly hard to believe that recovering from covid infection does not afford some level of immunity. I do wonder if recovery due to anti-virals prevents or weakens immunity, however.
- nostromo 7y ago
  Right. If our immune system didn't get better at fighting something, you would remain infected forever or die from it. Reference HIV as an example of a virus our immune system could not fight. If anyone is getting better (and 98%+ of people are) it's because the immune system can effectively fight it.
  - __blockcipher__ 7y ago
    Wow, I didn’t even think of it like that. That’s a great way to reason about it that makes it immediately clear. Thanks!
  - smaddox 7y ago
    Or it could go dormant, like the herpes virus.
- scotty79 7y ago
  Maybe it's sort of survivor bias. Maybe antivirals don't weaken immunity but people who survived thanks to antivirals have innately such a weak immune response that they wouldn't have survived without them.
  - rv-de 7y ago
    Huh? Antivirals just eliminate the virus before the immune system gets a chance to step in and build up immunity. How about that?
    - scotty79 7y ago
      I don't think that's true. I don't think they give antivirals to people before they have fever. And fever is one of the results of immune system working.
lend000 7y ago
With any non-negligible immunity rate (for example, 70% would be typical for immunity gained through an influenza vaccine [0]), we will still see exponential decay once a critical mass (R0 < 1) is reached. I believe immunity rates are higher after recovering from real infections, but still not perfect. Therefore a headline reading "Japanese man gets reinfected" is not of particular concern while "50% of survivors get reinfected" would be highly concerning. [0] https://www.ecdc.europa.eu/en/seasonal-influenza/prevention-and-control/vaccines/immunity https://www.ecdc.europa.eu/en/seasonal-influenza/prevention-...
- wycy 7y ago
  Interesting, I wasn’t aware immunity works this way. Thanks
pacetherace 7y ago
Viruses do mutate. So for many people, the body may never develop complete immunity.
- nostromo 7y ago
  SARS (including this new Coronavirus) does not mutate nearly as fast as the flu and other viruses though. It has built in error correction, and this is good news for us: > But SARS has a molecular proofreading system that reduces its mutation rate, and the new coronavirus’s similarity to SARS at the genomic level suggests it does, too. “That makes the mutation rate much, much lower than for flu or HIV,” Farzan said. That lowers the chance that the virus will evolve in some catastrophic way to, say, become significantly more lethal. https://www.statnews.com/2020/02/04/two-scenarios-if-new-coronavirus-isnt-contained/ https://www.statnews.com/2020/02/04/two-scenarios-if-new-cor...
chobytes 7y ago
the models already account for this. eg in compartmental models both SIS or SIRS have this assumption.
fuckknows 7y ago
Your prior should be that immunity works as it does with every other virus and you should require very strong evidence to the contrary (evidence, not anecdotes) to convince you otherwise. Throughout our evolutionary history we have come into contact with innumerable viruses and to a greater or lesser extent we have immunity to all of them post exposure. For many our immunity is long lived, on the order of years.
vinni2 7y ago
Doesn’t swine flu recur every now and then? Every virus could potentially become endemic.
- deleted 7y ago
  [deleted]

by wycy 7y ago

chickenpotpie 7y ago

Is it at all possible that we become progressively more immune with each incidence or that we can only be infected N times? If either of these things are true our strategy will still work.

dooglius 7y ago

It's not a boolean whether people become immune or not--maybe some small portion of the population have issues developing immunity and the rest are fine?

__blockcipher__ 7y ago
My reasoning is the same, but rather than it being binary, it’s a gradient. So after recovery I might be able to ward off 80% of exposure events that would infect a non-immune person. But given enough exposures or just really bad luck, I could still get infected again. That being said generally in these cases the infection resolves way sooner due to the same mechanism that leads to immunity: immune “memory cells” which wait dormant, ready to start production of immune cels when exposed to the characteristic antigens

__blockcipher__ 7y ago

I’m unaware of _any_ illness where some measure of immunity is not developed. I find it incredibly hard to believe that recovering from covid infection does not afford some level of immunity. I do wonder if recovery due to anti-virals prevents or weakens immunity, however.

nostromo 7y ago
Right. If our immune system didn't get better at fighting something, you would remain infected forever or die from it. Reference HIV as an example of a virus our immune system could not fight. If anyone is getting better (and 98%+ of people are) it's because the immune system can effectively fight it.
- __blockcipher__ 7y ago
  Wow, I didn’t even think of it like that. That’s a great way to reason about it that makes it immediately clear. Thanks!
- smaddox 7y ago
  Or it could go dormant, like the herpes virus.
scotty79 7y ago
Maybe it's sort of survivor bias. Maybe antivirals don't weaken immunity but people who survived thanks to antivirals have innately such a weak immune response that they wouldn't have survived without them.
- rv-de 7y ago
  Huh? Antivirals just eliminate the virus before the immune system gets a chance to step in and build up immunity. How about that?
  - scotty79 7y ago
    I don't think that's true. I don't think they give antivirals to people before they have fever. And fever is one of the results of immune system working.

lend000 7y ago

With any non-negligible immunity rate (for example, 70% would be typical for immunity gained through an influenza vaccine [0]), we will still see exponential decay once a critical mass (R0 < 1) is reached. I believe immunity rates are higher after recovering from real infections, but still not perfect. Therefore a headline reading "Japanese man gets reinfected" is not of particular concern while "50% of survivors get reinfected" would be highly concerning. [0] https://www.ecdc.europa.eu/en/seasonal-influenza/prevention-and-control/vaccines/immunity https://www.ecdc.europa.eu/en/seasonal-influenza/prevention-...

wycy 7y ago
Interesting, I wasn’t aware immunity works this way. Thanks

pacetherace 7y ago

Viruses do mutate. So for many people, the body may never develop complete immunity.

nostromo 7y ago
SARS (including this new Coronavirus) does not mutate nearly as fast as the flu and other viruses though. It has built in error correction, and this is good news for us: > But SARS has a molecular proofreading system that reduces its mutation rate, and the new coronavirus’s similarity to SARS at the genomic level suggests it does, too. “That makes the mutation rate much, much lower than for flu or HIV,” Farzan said. That lowers the chance that the virus will evolve in some catastrophic way to, say, become significantly more lethal. https://www.statnews.com/2020/02/04/two-scenarios-if-new-coronavirus-isnt-contained/ https://www.statnews.com/2020/02/04/two-scenarios-if-new-cor...

chobytes 7y ago

the models already account for this. eg in compartmental models both SIS or SIRS have this assumption.

fuckknows 7y ago

Your prior should be that immunity works as it does with every other virus and you should require very strong evidence to the contrary (evidence, not anecdotes) to convince you otherwise. Throughout our evolutionary history we have come into contact with innumerable viruses and to a greater or lesser extent we have immunity to all of them post exposure. For many our immunity is long lived, on the order of years.

vinni2 7y ago

Doesn’t swine flu recur every now and then? Every virus could potentially become endemic.

deleted 7y ago
[deleted]