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A lockdown is not supposed to reduce the total number of cases; it is supposed to "flatten the curve" so those cases take a lot longer to develop. The intent i

A lockdown is not supposed to reduce the total number of cases; it is supposed to "flatten the curve" so those cases take a lot longer to develop. The intent is to drag the virus out for as long as possible so we can prepare our hospitals, develop more effective treatments, and get closer to a vaccine. A lockdown does not make the virus go away sooner; it prolongs it. According to the Johns Hopkins dashboard[0], India has peeked. Just like most other nations, India seems to have made it through the worst of it and is now on a downward trend. That is the mystery. The article makes a few suggestions. Maybe the virus hindered by the warmer climate. Maybe the strain in India is weaker than others. Maybe India's relatively young population is just more resilient. Unfortunately, we just don't know yet. [0] https://www.arcgis.com/apps/opsdashboard/index.html#/bda7594740fd40299423467b48e9ecf6 https://www.arcgis.com/apps/opsdashboard/index.html#/bda7594...

marcosdumay 7y ago
Obviously a lockdown can cause the number of cases to go down. There's no mystery here. There are many countries doing the same. Yes, it is "supposed" to flatten the curve always keeping some manageable number of people infected. So if you reduce the number of cases any further you are doing it wrong; because no, you won't extinguish the virus, you'll only prolong the lockdown.
- CivBase 7y ago
  > Obviously a lockdown can cause the number of cases to go down. Maybe I'm just ignorant, but could you explain how a lockdown is supposed to decrease the total number of cases rather than just prolong it? A lockdown does not make a population more resilient to a virus. It just reduces contagion vectors so it spreads more slowly. The virus still spreads, though. Eventually, enough of the population will catch the virus and build up a resistance to it so that herd immunity kicks in. At that point, enough people will have been exposed to the virus that it does not have enough people to spread to and simply dies out. I suppose the threshold for herd immunity is lower in a lockdown situation, but I am skeptical about it working to that extent. If my skepticism is misplaced and the lockdown really is that effective, then that also means India will have to stay on lockdown for a very long time to keep that herd immunity threshold low and completely starve the virus out.
  - pjc50 7y ago
    Once you get "R" below 1, the number of cases goes down. Once the number of cases is small enough, you can identify and quarantine all of them. With a good enough testing infrastructure this gets easier. You can then have a "selective" lockdown only around actual cases.
    - jfoster 7y ago
      Yes. A bunch of countries have entered (or are about to enter) this phase: New Zealand, Australia, South Korea, Taiwan
    - CivBase 7y ago
      > Once the number of cases is small enough, you can identify and quarantine all of them. A nation is not a closed system so I don't see that ever working out.
      - fulafel 7y ago
        What about the eventual vaccine?
  - twomoretime 7y ago
    >Maybe I'm just ignorant, but could you explain how a lockdown is supposed to decrease the total number of cases rather than just prolong it It's not so black and white. We're talking about the area under the curve. The area under the curve varies nonlinearly with R0. But yes, because of the nature of the logistic function, a flatter curve will lead to fewer cases overall, once you factor in time and the assumption that eventually for whatever reason it will go away.
- kumarvvr 7y ago
  So what do you think is the alternative?
  - marcosdumay 7y ago
    Reduce activity as little as possible (if your local health care is overwelmend, that is a total lockdown), and keep watching the curve. If you get spare health care capacity, free people a bit, if that capacity fills-up put restrictions back.
- Tomminn 7y ago
  You can absolutely extinguish the virus if you have good border control. What makes you think you can't? The infection numbers exponentially decay toward zero when the replication rate is below one. At some point, the last infection recovers or dies without passing it on, and the virus is gone.
segmondy 7y ago
Nah, a stay at home order is to flatten the curve. A lockdown is to burnout the virus. If you lockdown for about 2x the time the virus incubates and people follow the lockdown. You can snuff the virus out. At the beginning of the lockdown, assume someone just got it and lives at home with others no symptoms but they spread it to other's that live at home, assume those don't have symptoms and they stay in for the recommended quarantine period, then the virus should have subsided. In the case of sars-cov-2 2weeks+2weeks. So 4 weeks minimum, add 1 or 2 more for safety measure. If people are sick enough to go to the hospital, they get treated, contact tracing is done. It's tough, but if everyone said home for 6 weeks. Absolutely no contact, the virus will burn out since it won't have any new hosts to infect. China didn't do their lockdown to flatten the curve, they did it to snuff out the virus, that's the same strategy India is attempting.
- solarkraft 7y ago
  Snuffing out the virus would be a pretty impressive feat and it might just work. It might even be awesome for a while - but wouldn't you have to completely eliminate any potential vectors for the virus to get into the country again? Does that really mean virtually no immigration? Even with rigorous testing, if there's a single false negative, wouldn't that completely eliminate the gains of having gotten rid of the virus?

marcosdumay 7y ago

Obviously a lockdown can cause the number of cases to go down. There's no mystery here. There are many countries doing the same. Yes, it is "supposed" to flatten the curve always keeping some manageable number of people infected. So if you reduce the number of cases any further you are doing it wrong; because no, you won't extinguish the virus, you'll only prolong the lockdown.

CivBase 7y ago
> Obviously a lockdown can cause the number of cases to go down. Maybe I'm just ignorant, but could you explain how a lockdown is supposed to decrease the total number of cases rather than just prolong it? A lockdown does not make a population more resilient to a virus. It just reduces contagion vectors so it spreads more slowly. The virus still spreads, though. Eventually, enough of the population will catch the virus and build up a resistance to it so that herd immunity kicks in. At that point, enough people will have been exposed to the virus that it does not have enough people to spread to and simply dies out. I suppose the threshold for herd immunity is lower in a lockdown situation, but I am skeptical about it working to that extent. If my skepticism is misplaced and the lockdown really is that effective, then that also means India will have to stay on lockdown for a very long time to keep that herd immunity threshold low and completely starve the virus out.
- pjc50 7y ago
  Once you get "R" below 1, the number of cases goes down. Once the number of cases is small enough, you can identify and quarantine all of them. With a good enough testing infrastructure this gets easier. You can then have a "selective" lockdown only around actual cases.
  - jfoster 7y ago
    Yes. A bunch of countries have entered (or are about to enter) this phase: New Zealand, Australia, South Korea, Taiwan
  - CivBase 7y ago
    > Once the number of cases is small enough, you can identify and quarantine all of them. A nation is not a closed system so I don't see that ever working out.
    - fulafel 7y ago
      What about the eventual vaccine?
- twomoretime 7y ago
  >Maybe I'm just ignorant, but could you explain how a lockdown is supposed to decrease the total number of cases rather than just prolong it It's not so black and white. We're talking about the area under the curve. The area under the curve varies nonlinearly with R0. But yes, because of the nature of the logistic function, a flatter curve will lead to fewer cases overall, once you factor in time and the assumption that eventually for whatever reason it will go away.
kumarvvr 7y ago
So what do you think is the alternative?
- marcosdumay 7y ago
  Reduce activity as little as possible (if your local health care is overwelmend, that is a total lockdown), and keep watching the curve. If you get spare health care capacity, free people a bit, if that capacity fills-up put restrictions back.
Tomminn 7y ago
You can absolutely extinguish the virus if you have good border control. What makes you think you can't? The infection numbers exponentially decay toward zero when the replication rate is below one. At some point, the last infection recovers or dies without passing it on, and the virus is gone.

segmondy 7y ago

Nah, a stay at home order is to flatten the curve. A lockdown is to burnout the virus. If you lockdown for about 2x the time the virus incubates and people follow the lockdown. You can snuff the virus out. At the beginning of the lockdown, assume someone just got it and lives at home with others no symptoms but they spread it to other's that live at home, assume those don't have symptoms and they stay in for the recommended quarantine period, then the virus should have subsided. In the case of sars-cov-2 2weeks+2weeks. So 4 weeks minimum, add 1 or 2 more for safety measure. If people are sick enough to go to the hospital, they get treated, contact tracing is done. It's tough, but if everyone said home for 6 weeks. Absolutely no contact, the virus will burn out since it won't have any new hosts to infect. China didn't do their lockdown to flatten the curve, they did it to snuff out the virus, that's the same strategy India is attempting.

solarkraft 7y ago
Snuffing out the virus would be a pretty impressive feat and it might just work. It might even be awesome for a while - but wouldn't you have to completely eliminate any potential vectors for the virus to get into the country again? Does that really mean virtually no immigration? Even with rigorous testing, if there's a single false negative, wouldn't that completely eliminate the gains of having gotten rid of the virus?