6 ms·

20%. Yay? How much longer until herd immunity?

LatteLazy 6y ago
That would be at around 80%, the US got going in April, so that was 8 months, so another 24 months and we should be there, assuming no change in spread rate (seems unlikely but Im a rando off the net so what do I know?)
- pjc50 6y ago
  Another 24 months at 3,000 deaths per day, would be approximately two million people or one New Mexico.
- totony 6y ago
  Where did you get 80% from? A nature article seemed to suggest anywhere from ~50% to 70%
- AnimalMuppet 6y ago
  Why do you say 80%? What's your value of R0 (before people changed behavior, to the degree that they did)? In my (admittedly naive) thinking, if R0 was 2, say, then if 50% of the people got it (and were therefore not able to get it again, and therefore not able to spread it), then the effective R0 would be 1.
  - LatteLazy 6y ago
    I picked 80 because it was 4 times the 20% we already got. I wasn't really trying to be accurate, I think we'd need to look at an exponential as the R value drops as the already infected rate goes up? Not sure... :) Isn't the R0 for "no restrictions" something like 15? So I'd guess we'd need 93%? But I also have seen figures from 50 to 95% quoted for herd immunity so who knows?
    - AnimalMuppet 6y ago
      No, it's nowhere near 15. Measles is 12, and measles is far worse than Covid. I seem to recall seeing 1.3 for Covid, but that could have been after masking, quarantining, or both. Anyone with real numbers, feel free to supply them...
  - ddingus 6y ago
    They can get it again. Immunity varies, but is not permanent.
xfitm3 6y ago
I'd love for it to speed up and return to a sense of normality. I'm sure we can all agree it's been a terrible year.
deelowe 6y ago
Much longer than most assume. The virus has a pretty high r0 when restrictions are lifted.
lock-free 6y ago
Not until the population is vaccinated, like polio, smallpox or most other diseases where you can be reinfected...
titzer 6y ago
> herd immunity The word you are looking for is endemic, i.e. never goes away and cannot be effectively eradicated. Congratulations on adding another biological landmine to modern existence.
- woofie11 6y ago
  Maybe. There are two ways this goes: 1) 3.4% of people who catch it die every year, and life changes 2) It mutates, and gets worse. Unlikely, but not impossible. Or it leads to long-term disability which we don't know about yet (not unlikely). Etc. 3) Kids get it early, acquire partial immunity as it passes, and it becomes another variant of the common cold/flu. Most of the time, #3 is the outcome. It's worth taking seriously because #1 and #2 will eventually happen if we ignore these, but....
  - anoncake 6y ago
    > 1) 3.4% of people who catch it die every year, and life changes Why do you think the IFR will increase by a factor of almost 7?
    - woofie11 6y ago
      Massachusetts, which has good test infrastructure, had 280k cases, and 11k deaths. That's 3.9%, excluding people who have yet to die. That was also WHO's first estimate (3.4%). I'm now seeing WHO is estimating 0.5-1.0%, which is possible too. I don't think we'll know for some time. One of the problems is people who have yet to die... You can't get a good estimate until long after a pandemic, to catch all the stragglers.
      - anoncake 6y ago
        Unless Massachusetts somehow manages to capture 100% of infections, that's the case fatality rate, which is worthless except as raw data to estimate the infection fatality rate. The 3.4% "estimate" also referred to the IFR as far as I know and if it didn't, it would also be worthless now anyway as it has been superseded.
tinus_hn 6y ago
Sorry, the HackerNews hive mind doesn’t allow the use of that term.

That would be at around 80%, the US got going in April, so that was 8 months, so another 24 months and we should be there, assuming no change in spread rate (seems unlikely but Im a rando off the net so what do I know?)

pjc50 6y ago
Another 24 months at 3,000 deaths per day, would be approximately two million people or one New Mexico.
totony 6y ago
Where did you get 80% from? A nature article seemed to suggest anywhere from ~50% to 70%
AnimalMuppet 6y ago
Why do you say 80%? What's your value of R0 (before people changed behavior, to the degree that they did)? In my (admittedly naive) thinking, if R0 was 2, say, then if 50% of the people got it (and were therefore not able to get it again, and therefore not able to spread it), then the effective R0 would be 1.
- LatteLazy 6y ago
  I picked 80 because it was 4 times the 20% we already got. I wasn't really trying to be accurate, I think we'd need to look at an exponential as the R value drops as the already infected rate goes up? Not sure... :) Isn't the R0 for "no restrictions" something like 15? So I'd guess we'd need 93%? But I also have seen figures from 50 to 95% quoted for herd immunity so who knows?
  - AnimalMuppet 6y ago
    No, it's nowhere near 15. Measles is 12, and measles is far worse than Covid. I seem to recall seeing 1.3 for Covid, but that could have been after masking, quarantining, or both. Anyone with real numbers, feel free to supply them...
- ddingus 6y ago
  They can get it again. Immunity varies, but is not permanent.

xfitm3 6y ago

I'd love for it to speed up and return to a sense of normality. I'm sure we can all agree it's been a terrible year.

deelowe 6y ago

Much longer than most assume. The virus has a pretty high r0 when restrictions are lifted.

lock-free 6y ago

Not until the population is vaccinated, like polio, smallpox or most other diseases where you can be reinfected...

titzer 6y ago

> herd immunity The word you are looking for is endemic, i.e. never goes away and cannot be effectively eradicated. Congratulations on adding another biological landmine to modern existence.

woofie11 6y ago
Maybe. There are two ways this goes: 1) 3.4% of people who catch it die every year, and life changes 2) It mutates, and gets worse. Unlikely, but not impossible. Or it leads to long-term disability which we don't know about yet (not unlikely). Etc. 3) Kids get it early, acquire partial immunity as it passes, and it becomes another variant of the common cold/flu. Most of the time, #3 is the outcome. It's worth taking seriously because #1 and #2 will eventually happen if we ignore these, but....
- anoncake 6y ago
  > 1) 3.4% of people who catch it die every year, and life changes Why do you think the IFR will increase by a factor of almost 7?
  - woofie11 6y ago
    Massachusetts, which has good test infrastructure, had 280k cases, and 11k deaths. That's 3.9%, excluding people who have yet to die. That was also WHO's first estimate (3.4%). I'm now seeing WHO is estimating 0.5-1.0%, which is possible too. I don't think we'll know for some time. One of the problems is people who have yet to die... You can't get a good estimate until long after a pandemic, to catch all the stragglers.
    - anoncake 6y ago
      Unless Massachusetts somehow manages to capture 100% of infections, that's the case fatality rate, which is worthless except as raw data to estimate the infection fatality rate. The 3.4% "estimate" also referred to the IFR as far as I know and if it didn't, it would also be worthless now anyway as it has been superseded.

tinus_hn 6y ago

Sorry, the HackerNews hive mind doesn’t allow the use of that term.