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Ah, clinging to the old fantasy of ‘low R values’, as if somehow that will cause the pandemic to disappear. In reality that outcome will online happen when ther

Ah, clinging to the old fantasy of ‘low R values’, as if somehow that will cause the pandemic to disappear. In reality that outcome will online happen when there are exactly 0 cases left, both in humans and animals, in any country in the world. Spoiler: that’s never going to happen.

cameldrv 4y ago
The fantasy is a reality in China. It's not necessary to get to zero cases to have a disease simply not be a major problem, similar to Measles in the U.S. In the general population for Measles R<1, so while it pops up from time to time in some poorly vaccinated communities, for the general population that's been vaccinated, it's really not an issue. The fantasy with COVID was that you'd get R<1 for a period of time until there was a vaccine, and then the vaccine would do all of the work keeping R<1. Unfortunately the COVID vaccine doesn't do that. Hopefully some day we will have one that does that.
- tinus_hn 4y ago
  Well I don’t know what the mainstream theory was in the US but in the Netherlands it was ‘well if due to our lockdowns R is smaller than 1 the disease will just die down’. Which is obviously nonsensical in a pandemic.
  - cameldrv 4y ago
    If R is lower than 1, the disease will die down. If it's greater than 1 it will flare up (by definition). China has reached a stage where they have essentially eradicated it within China. They still import cases though into areas where R>1. When that happens, they get a flare up, and then they clamp down with massive testing and, if it gets bad enough, lockdowns, until they eradicate it from that area again. Now at the beginning, one strategy could have been: get R much lower than 1, and push the disease to near eradication, and then dynamically change anti-covid measures so that R approximately equaled 1, which would entail substantial restrictions, but not a Wuhan or Shanghai style lockdown. The problem is that riding along at exactly R=1 means any time the seasons change, or there's a new variant, or people's behavior changes, you have to constantly adjust restrictions. Generally it has been shown to be impossible in democracies to get enough people to agree to do this, and it's generally not politically possible to enforce this. Once the vaccines came out, the hope was always that they would dramatically reduce transmission so that R was much less than 1 and we could treat it like measles, and for a while (mid-2021, pre-Delta) that seemed to be the case, but between waning immunity and Omicron, it turned out that the vaccines were not able to reduce transmission to a great enough degree to make this happen.
    - tinus_hn 4y ago
      The vaccines were tested and approved so scientifically it should have been known before the rollout started that it wouldn’t work. So once the vaccines were approved (December 2020) either we knew all along it wasn’t going to work and the R values theory was just psuedoscientific fraud to get the population to comply, or we didn’t know and the approval process was faulty. Either way the R values theory was never going to work because there was always going to be a big part of the population (animals, people abroad) that can’t be controlled with lockdowns or vaccine mandates. And that also should have been known. And lastly, R values theories make for nice, easy to explain pop science, but it’s all statistics with all the downsides: the R value that’s on the news is just a number calculated from limited tests, and those tests can be manipulated. And it’s part of a random process; R>1 doesn’t ‘mean flare ups will occur’. It means the chance is higher that the numbers will go up. But they can also randomly go down. All interesting for pop science and for making models and reports but a lot less useful for political decisionmaking in the real world.
      - cameldrv 4y ago
        The vaccines were not approved on the basis that they reduced transmission. This was a widely held hope, given that other vaccines do this, but that wasn't an endpoint of the studies. There was a little bit of data in the Moderna trial that was very encouraging, namely that everyone in the trial took a PCR test at the time of their second dose, and people in the active arm had a much lower positivity rate. There was also a lot of epidemiological evidence for the vaccines dramatically reducing transmission. The problem is that this data was gathered with a different version of the virus than we have now, and it was gathered with relatively fresh vaccinations. Even pre-Delta, you could see immunity waning leading to increased transmission in Israel. With Omicron, the efficacy of the vaccines is also much less. That said, from all the evidence we have, the existing vaccines still do reduce transmission, but not enough to prevent epidemic spread. There are a lot of numbers, because every study has a different population and different ways of measuring, but roughly speaking, being vaccinated cuts your risk of contracting and transmitting COVID by something on the order of 50%. That's a lot better than nothing, but COVID is so contagious that it's not enough. The "R values theory" is perfectly reasonable and almost tautologically correct, and works regardless of an animal reservoir and imported cases from travel. We have the same issue with imported cases with Measles, but hardly anyone gets Measles, because almost everyone is vaccinated, and the R value in the population is much less than 1. If you import a case, that case infects less than 1 person on average, who infects less than 1 person on average, etc, until it dies out. R<<1 doesn't mean you have no cases, it just means that it's self limiting. If you import say, 100 cases a year, maybe that leads to 50 or 100 locally acquired cases total, but for the average person, you don't really have to worry about it. The exception is communities with low vaccination rates. You sometimes see Measles pop up still in the U.S. in religious communities, etc, because R for Measles in those communities is greater than 1 due to the lack of vaccination. It would be great if COVID and COVID vaccines were like Measles, but unfortunately the vaccine isn't yet good enough.

cameldrv 4y ago

The fantasy is a reality in China. It's not necessary to get to zero cases to have a disease simply not be a major problem, similar to Measles in the U.S. In the general population for Measles R<1, so while it pops up from time to time in some poorly vaccinated communities, for the general population that's been vaccinated, it's really not an issue. The fantasy with COVID was that you'd get R<1 for a period of time until there was a vaccine, and then the vaccine would do all of the work keeping R<1. Unfortunately the COVID vaccine doesn't do that. Hopefully some day we will have one that does that.

tinus_hn 4y ago
Well I don’t know what the mainstream theory was in the US but in the Netherlands it was ‘well if due to our lockdowns R is smaller than 1 the disease will just die down’. Which is obviously nonsensical in a pandemic.
- cameldrv 4y ago
  If R is lower than 1, the disease will die down. If it's greater than 1 it will flare up (by definition). China has reached a stage where they have essentially eradicated it within China. They still import cases though into areas where R>1. When that happens, they get a flare up, and then they clamp down with massive testing and, if it gets bad enough, lockdowns, until they eradicate it from that area again. Now at the beginning, one strategy could have been: get R much lower than 1, and push the disease to near eradication, and then dynamically change anti-covid measures so that R approximately equaled 1, which would entail substantial restrictions, but not a Wuhan or Shanghai style lockdown. The problem is that riding along at exactly R=1 means any time the seasons change, or there's a new variant, or people's behavior changes, you have to constantly adjust restrictions. Generally it has been shown to be impossible in democracies to get enough people to agree to do this, and it's generally not politically possible to enforce this. Once the vaccines came out, the hope was always that they would dramatically reduce transmission so that R was much less than 1 and we could treat it like measles, and for a while (mid-2021, pre-Delta) that seemed to be the case, but between waning immunity and Omicron, it turned out that the vaccines were not able to reduce transmission to a great enough degree to make this happen.
  - tinus_hn 4y ago
    The vaccines were tested and approved so scientifically it should have been known before the rollout started that it wouldn’t work. So once the vaccines were approved (December 2020) either we knew all along it wasn’t going to work and the R values theory was just psuedoscientific fraud to get the population to comply, or we didn’t know and the approval process was faulty. Either way the R values theory was never going to work because there was always going to be a big part of the population (animals, people abroad) that can’t be controlled with lockdowns or vaccine mandates. And that also should have been known. And lastly, R values theories make for nice, easy to explain pop science, but it’s all statistics with all the downsides: the R value that’s on the news is just a number calculated from limited tests, and those tests can be manipulated. And it’s part of a random process; R>1 doesn’t ‘mean flare ups will occur’. It means the chance is higher that the numbers will go up. But they can also randomly go down. All interesting for pop science and for making models and reports but a lot less useful for political decisionmaking in the real world.
    - cameldrv 4y ago
      The vaccines were not approved on the basis that they reduced transmission. This was a widely held hope, given that other vaccines do this, but that wasn't an endpoint of the studies. There was a little bit of data in the Moderna trial that was very encouraging, namely that everyone in the trial took a PCR test at the time of their second dose, and people in the active arm had a much lower positivity rate. There was also a lot of epidemiological evidence for the vaccines dramatically reducing transmission. The problem is that this data was gathered with a different version of the virus than we have now, and it was gathered with relatively fresh vaccinations. Even pre-Delta, you could see immunity waning leading to increased transmission in Israel. With Omicron, the efficacy of the vaccines is also much less. That said, from all the evidence we have, the existing vaccines still do reduce transmission, but not enough to prevent epidemic spread. There are a lot of numbers, because every study has a different population and different ways of measuring, but roughly speaking, being vaccinated cuts your risk of contracting and transmitting COVID by something on the order of 50%. That's a lot better than nothing, but COVID is so contagious that it's not enough. The "R values theory" is perfectly reasonable and almost tautologically correct, and works regardless of an animal reservoir and imported cases from travel. We have the same issue with imported cases with Measles, but hardly anyone gets Measles, because almost everyone is vaccinated, and the R value in the population is much less than 1. If you import a case, that case infects less than 1 person on average, who infects less than 1 person on average, etc, until it dies out. R<<1 doesn't mean you have no cases, it just means that it's self limiting. If you import say, 100 cases a year, maybe that leads to 50 or 100 locally acquired cases total, but for the average person, you don't really have to worry about it. The exception is communities with low vaccination rates. You sometimes see Measles pop up still in the U.S. in religious communities, etc, because R for Measles in those communities is greater than 1 due to the lack of vaccination. It would be great if COVID and COVID vaccines were like Measles, but unfortunately the vaccine isn't yet good enough.