5 ms·

From that stat alone, not very much. - Your best estimate on a do nothing strategy would be that total deaths would be 20x what it currently is, (I'd assume e

From that stat alone, not very much. - Your best estimate on a do nothing strategy would be that total deaths would be 20x what it currently is, (I'd assume everyone catches covid before herd immunity becomes relevant: here, aiming for herd immunity is a different strategy than 'do nothing') - plus likely a whole bunch more due to overwhelmed health services, likely a large proportion of people needing intensive care would also have died, - plus likely a whole bunch more people would have had a high viral load initial exposure and more likely to have consequential symptoms, - plus likely a whole bunch more, reflecting a likely relatively safe age and risk distribution of people who have caught covid to date.

jtbayly 6y ago
> I'd assume everyone catches covid before herd immunity becomes relevant... That's just not how it works. As the number of immune people (whether through survival, natural immunity or vaccine) in a population increases, the chances of anybody who is contagious spreading the disease begins to decrease. Herd immunity is going to be reached before everybody catches it, no matter what.
- andy_ppp 6y ago
  Yes I read 60-70% is enough for herd immunity.
- marcosdumay 6y ago
  It takes weeks before people stop being contagious. That's plenty of time to pass it around to everybody in a "do nothing" scenario. (Of course, that is in a naive model with homogeneous population. If we've learned anything from this pandemic is that the population is heterogeneous enough for breaking those.)
  - nradov 6y ago
    That is not correct. The vast majority of patients stop being contagious within 10 days of infection. https://www.evms.edu/media/evms_public/departments/internal_medicine/EVMS_Critical_Care_COVID-19_Protocol.pdf https://www.evms.edu/media/evms_public/departments/internal_... Patients may continue have positive PCR test results for weeks, but that doesn't mean they are contagious.
    - throwaway2245 6y ago
      >The vast majority of patients stop being contagious within 10 days of infection. Nonetheless, if growth starts out exponential then a majority of people would have been recently enough infected.
      - jtbayly 6y ago
        You need to play around with a simple herd immunity model. You'll see what I'm talking about.
- throwaway2245 6y ago
  This makes a fractional difference at most. And, I disagree on the following grounds - Let's say we assume the point of herd immunity is when 60% are infected (which I also doubt: models were not taking into account superspreading events when this was established as an estimate) Then we can agree that if ~60% of the population is seropositive and no longer infectious, everyone (everyone else) is now safe. Cool. However, if there is uncontrolled infection, then we reach the 60% mark of herd immunity, you bust through that ceiling because most people are still infectious and continuing to infect others.
  - jtbayly 6y ago
    Herd immunity will be reached at a percent of the population being infected. What percent that is depends on a lot of factors, including the rate of infection (R0), the length of contagion, etc. Nevertheless, herd immunity will be reached at less than 100% infected with Covid-19. I'm not saying that it will be as low as 60%. I highly doubt that. I'd say closer to 80-85%, as a guess based on my simplistic math. I'm no epidemiologist. Then again, neither are you, I'm guessing. :) Months ago there was a fascinating link on HN that had models you could play with to adjust all the variables in a simple model. You should find it and play around. I'll try to find a link when I can come back to this later.
    - throwaway2245 6y ago
      OK, I get you. In my model of no changed behaviour, people who are coincidentally isolated during the final weeks of virulent spread might ultimately avoid infection. That's still going to be 99%, 98% infected? 95% seems doubtful to me under that model - but perhaps you are right. 100% with a rounding error.
      - jtbayly 6y ago
        Your model is absurd. In what world would nobody change their behavior?
        deleted 6y ago
- jhayward 6y ago
  > * Herd immunity is going to be reached before everybody catches it, no matter what* That’s only true for a very slow-moving epidemic. For a fast mover, like this one, there is always -always- an overshoot of the steady state number needed for “herd immunity” (which, btw, is a term created to describe vaccinated populations, not wild infections).
  - jtbayly 6y ago
    No. It's true for every epidemic except extremely fast-moving and long-lasting ones. Covid is not that.
    - jhayward 6y ago
      Public health and epidemiology professionals say otherwise. https://www.nytimes.com/2020/05/01/opinion/sunday/coronavirus-herd-immunity.html https://www.nytimes.com/2020/05/01/opinion/sunday/coronaviru...
      - jtbayly 6y ago
        That article literally shows less than 100% of people getting Covid.

jtbayly 6y ago

> I'd assume everyone catches covid before herd immunity becomes relevant... That's just not how it works. As the number of immune people (whether through survival, natural immunity or vaccine) in a population increases, the chances of anybody who is contagious spreading the disease begins to decrease. Herd immunity is going to be reached before everybody catches it, no matter what.

andy_ppp 6y ago
Yes I read 60-70% is enough for herd immunity.
marcosdumay 6y ago
It takes weeks before people stop being contagious. That's plenty of time to pass it around to everybody in a "do nothing" scenario. (Of course, that is in a naive model with homogeneous population. If we've learned anything from this pandemic is that the population is heterogeneous enough for breaking those.)
- nradov 6y ago
  That is not correct. The vast majority of patients stop being contagious within 10 days of infection. https://www.evms.edu/media/evms_public/departments/internal_medicine/EVMS_Critical_Care_COVID-19_Protocol.pdf https://www.evms.edu/media/evms_public/departments/internal_... Patients may continue have positive PCR test results for weeks, but that doesn't mean they are contagious.
  - throwaway2245 6y ago
    >The vast majority of patients stop being contagious within 10 days of infection. Nonetheless, if growth starts out exponential then a majority of people would have been recently enough infected.
    - jtbayly 6y ago
      You need to play around with a simple herd immunity model. You'll see what I'm talking about.
throwaway2245 6y ago
This makes a fractional difference at most. And, I disagree on the following grounds - Let's say we assume the point of herd immunity is when 60% are infected (which I also doubt: models were not taking into account superspreading events when this was established as an estimate) Then we can agree that if ~60% of the population is seropositive and no longer infectious, everyone (everyone else) is now safe. Cool. However, if there is uncontrolled infection, then we reach the 60% mark of herd immunity, you bust through that ceiling because most people are still infectious and continuing to infect others.
- jtbayly 6y ago
  Herd immunity will be reached at a percent of the population being infected. What percent that is depends on a lot of factors, including the rate of infection (R0), the length of contagion, etc. Nevertheless, herd immunity will be reached at less than 100% infected with Covid-19. I'm not saying that it will be as low as 60%. I highly doubt that. I'd say closer to 80-85%, as a guess based on my simplistic math. I'm no epidemiologist. Then again, neither are you, I'm guessing. :) Months ago there was a fascinating link on HN that had models you could play with to adjust all the variables in a simple model. You should find it and play around. I'll try to find a link when I can come back to this later.
  - throwaway2245 6y ago
    OK, I get you. In my model of no changed behaviour, people who are coincidentally isolated during the final weeks of virulent spread might ultimately avoid infection. That's still going to be 99%, 98% infected? 95% seems doubtful to me under that model - but perhaps you are right. 100% with a rounding error.
    - jtbayly 6y ago
      Your model is absurd. In what world would nobody change their behavior?
      - deleted 6y ago
jhayward 6y ago
> * Herd immunity is going to be reached before everybody catches it, no matter what* That’s only true for a very slow-moving epidemic. For a fast mover, like this one, there is always -always- an overshoot of the steady state number needed for “herd immunity” (which, btw, is a term created to describe vaccinated populations, not wild infections).
- jtbayly 6y ago
  No. It's true for every epidemic except extremely fast-moving and long-lasting ones. Covid is not that.
  - jhayward 6y ago
    Public health and epidemiology professionals say otherwise. https://www.nytimes.com/2020/05/01/opinion/sunday/coronavirus-herd-immunity.html https://www.nytimes.com/2020/05/01/opinion/sunday/coronaviru...
    - jtbayly 6y ago
      That article literally shows less than 100% of people getting Covid.