4 ms·

Herd immunity through infection has never worked. It's incoherent even as a concept: to prevent infections, get infected? There are a few diseases better to ge

by graeme 4y ago

Herd immunity through infection has never worked. It's incoherent even as a concept: to prevent infections, get infected? There are a few diseases better to get as a kid than as an adult, but we mostly have vaccines for those now. And respiratory viruses aren't included in the category of those we need exposure to for immune system development. >In 2003 Graham Rook proposed the "old friends hypothesis" which has been described as a more rational explanation for the link between microbial exposure and inflammatory disorders.[20] The hypothesis states that the vital microbial exposures are not colds, influenza, measles and other common childhood infections which have evolved relatively recently over the last 10,000 years, but rather the microbes already present during mammalian and human evolution, that could persist in small hunter-gatherer groups as microbiota, tolerated latent infections, or carrier states. He proposed that coevolution with these species has resulted in their gaining a role in immune system development. https://en.wikipedia.org/wiki/Hygiene_hypothesis https://en.wikipedia.org/wiki/Hygiene_hypothesis

ars 4y ago
> It's incoherent even as a concept: to prevent infections, get infected? What's confusing? Get infected once, avoid tens of infections. If your immune system "forgets" the immunity after 6 months (which is the case for COVID), then every 4 months get exposed, you won't get actively sick since you still have some immunity, and you'll keep your immunity high.
- seadan83 4y ago
  Being exposed every 4 months is not quite herd immunity. Herd immunity is essentially: because some 95% of people are immune to smallpox, if there is an outbreak, it will not find any new hosts and would die out. That is very different from "get a booster (or re-infected) every X months to keep immune levels high". In other words, the rapid decay of individual immunity causes for there to be a loss in herd immunity (or herd immunity never achieved at all due to decay in immunity). From a contra-positive point of view, if there were herd immunity, then you would not be able to get re-infected every 4 months because there would be no carriers of the virus to infect you. I think the bottom line is that 'herd immunity' is only a concept if immunity is durable and long lasting. Otherwise that herd immunity decays too quickly and you wind up in a cycle where everyone gets infected, the infection levels drops off, that immunity wears off, rinse-wash repeat. Anecdotally, I was on a train recently and was talking to my neighbors where an elderly woman said casually that the 3rd time being infected she was in the hospital for only 7 days that time. The implication being that this part of the population could land in the hospital repeatedly every 4-6 months. I would wager that someone who is 65 to around 70 years old will survive covid related pneumonia only so many times before they don't. I think this speaks to how Covid is pretty vicious. And all that is to say that 'natural' herd immunity is not our ticket out of this problem (just based on the math). There may be no good tickets out of this short of everyone vaccinating every 6 months and also reducing transmission rates (eg: early detection and quarantining/masking to avoid infecting others, and reducing your own risk of infection via distancing/masking).
- autoexec 4y ago
  > What's confusing? Get infected once, avoid tens of infections. If your immune system "forgets" the immunity after 6 months (which is the case for COVID), then every 4 months get exposed, you won't get actively sick since you still have some immunity Another problem with this concept (at least for things like COVID) is that every time the virus is passed on it has a chance to mutate into something your immune system is unprepared for. Maybe you catch it and don't feel sick, or are only briefly/mildly sick, but you can still play host to it long enough for it to mutate and get passed to someone else. The more it moves from host to host the better it gets at surviving and defeating immune systems. Entire populations passing a virus back and forth at a high rate for long periods of time seems like a disaster waiting to happen.
  - ars 4y ago
    Is there any other option? Vaccination would not help because it works exactly the same way. Vaccination certainly helps for the initial response, so people don't get as sick. But after that natural immunity is superior to vaccination. But it's not true what you say, a mutated virus can still elicit a partial response. So if people are constantly exposed to the new virus they will never get seriously sick.
    - autoexec 4y ago
      > Is there any other option? Not spreading the virus around would be the ideal. If we got people protected with vaccines and kept community spread low the number of variants wouldn't rise as quickly. Fewer variants would mean vaccines would stay effective longer and we wouldn't be rolling the dice on any new nasty features as often. I don't think we can ever hope to eradicate the virus from the earth now that it's here, but we could do a lot more to keep it from spreading at the kinds of rates it has been. > Vaccination would not help because it works exactly the same way. Vaccination doesn't work the same way because you gain the immunity without having the virus. No virus in you, no chance for the virus to mutate or spread and then mutate. You might still get infected by someone else later, but you aren't depending on getting infected to maintain your immune system's preparedness and if community spread is low because people are vaccinating instead of virus swapping your odds of getting the actual virus will be low as well. > Vaccination certainly helps for the initial response, so people don't get as sick. But after that natural immunity is superior to vaccination. From the evidence we have right now a combination of vaccine+infection gives the most robust protection, however that still involves getting infected and taking your chances with lasting heart lung and kidney problems. In my book, not having to take my chances with complications or long covid more than makes up for the difference which makes vaccines without infection superior. The odds of ending up with long covid was 1 in 5 in a recent study (https://www.cdc.gov/mmwr/volumes/71/wr/mm7121e1.htm https://www.cdc.gov/mmwr/volumes/71/wr/mm7121e1.htm) but different variants will carry different levels of risk. Even if you like your odds today, if you're just passing the virus around incubating new variants all the time who knows what odds you'll end up with later. There's evidence that people who get reinfected with the virus have an increase in their risks for long covid too. > But it's not true what you say, a mutated virus can still elicit a partial response. It all depends on what the mutations are. If a virus changes enough it may no longer be recognizable as the virus you were previously infected with. We're somewhat lucky with Covid because its structure makes it less likely to mutate to the point where we don't get some kind of response, but it's already evolved so much that our first vaccines which were 90% effective at preventing infection while at full strength are now only 30-40% effective at preventing infection. The good news so far is that even the old vaccines are pretty effective against the most severe cases and death, but that too is subject to change. It's already looking like re-exposing your immune system has diminishing returns. That was one concern people had over recommending 4th doses of the original vaccines. The protection from infection people got from shot #4 didn't last nearly as long as it did after getting shot #3. I'm really hoping the new vaccines help with that. Right now people who get covid can get reinfected with the newest strain after just one month!

by graeme 4y ago

ars 4y ago

> It's incoherent even as a concept: to prevent infections, get infected? What's confusing? Get infected once, avoid tens of infections. If your immune system "forgets" the immunity after 6 months (which is the case for COVID), then every 4 months get exposed, you won't get actively sick since you still have some immunity, and you'll keep your immunity high.

seadan83 4y ago
Being exposed every 4 months is not quite herd immunity. Herd immunity is essentially: because some 95% of people are immune to smallpox, if there is an outbreak, it will not find any new hosts and would die out. That is very different from "get a booster (or re-infected) every X months to keep immune levels high". In other words, the rapid decay of individual immunity causes for there to be a loss in herd immunity (or herd immunity never achieved at all due to decay in immunity). From a contra-positive point of view, if there were herd immunity, then you would not be able to get re-infected every 4 months because there would be no carriers of the virus to infect you. I think the bottom line is that 'herd immunity' is only a concept if immunity is durable and long lasting. Otherwise that herd immunity decays too quickly and you wind up in a cycle where everyone gets infected, the infection levels drops off, that immunity wears off, rinse-wash repeat. Anecdotally, I was on a train recently and was talking to my neighbors where an elderly woman said casually that the 3rd time being infected she was in the hospital for only 7 days that time. The implication being that this part of the population could land in the hospital repeatedly every 4-6 months. I would wager that someone who is 65 to around 70 years old will survive covid related pneumonia only so many times before they don't. I think this speaks to how Covid is pretty vicious. And all that is to say that 'natural' herd immunity is not our ticket out of this problem (just based on the math). There may be no good tickets out of this short of everyone vaccinating every 6 months and also reducing transmission rates (eg: early detection and quarantining/masking to avoid infecting others, and reducing your own risk of infection via distancing/masking).
autoexec 4y ago
> What's confusing? Get infected once, avoid tens of infections. If your immune system "forgets" the immunity after 6 months (which is the case for COVID), then every 4 months get exposed, you won't get actively sick since you still have some immunity Another problem with this concept (at least for things like COVID) is that every time the virus is passed on it has a chance to mutate into something your immune system is unprepared for. Maybe you catch it and don't feel sick, or are only briefly/mildly sick, but you can still play host to it long enough for it to mutate and get passed to someone else. The more it moves from host to host the better it gets at surviving and defeating immune systems. Entire populations passing a virus back and forth at a high rate for long periods of time seems like a disaster waiting to happen.
- ars 4y ago
  Is there any other option? Vaccination would not help because it works exactly the same way. Vaccination certainly helps for the initial response, so people don't get as sick. But after that natural immunity is superior to vaccination. But it's not true what you say, a mutated virus can still elicit a partial response. So if people are constantly exposed to the new virus they will never get seriously sick.
  - autoexec 4y ago
    > Is there any other option? Not spreading the virus around would be the ideal. If we got people protected with vaccines and kept community spread low the number of variants wouldn't rise as quickly. Fewer variants would mean vaccines would stay effective longer and we wouldn't be rolling the dice on any new nasty features as often. I don't think we can ever hope to eradicate the virus from the earth now that it's here, but we could do a lot more to keep it from spreading at the kinds of rates it has been. > Vaccination would not help because it works exactly the same way. Vaccination doesn't work the same way because you gain the immunity without having the virus. No virus in you, no chance for the virus to mutate or spread and then mutate. You might still get infected by someone else later, but you aren't depending on getting infected to maintain your immune system's preparedness and if community spread is low because people are vaccinating instead of virus swapping your odds of getting the actual virus will be low as well. > Vaccination certainly helps for the initial response, so people don't get as sick. But after that natural immunity is superior to vaccination. From the evidence we have right now a combination of vaccine+infection gives the most robust protection, however that still involves getting infected and taking your chances with lasting heart lung and kidney problems. In my book, not having to take my chances with complications or long covid more than makes up for the difference which makes vaccines without infection superior. The odds of ending up with long covid was 1 in 5 in a recent study (https://www.cdc.gov/mmwr/volumes/71/wr/mm7121e1.htm https://www.cdc.gov/mmwr/volumes/71/wr/mm7121e1.htm) but different variants will carry different levels of risk. Even if you like your odds today, if you're just passing the virus around incubating new variants all the time who knows what odds you'll end up with later. There's evidence that people who get reinfected with the virus have an increase in their risks for long covid too. > But it's not true what you say, a mutated virus can still elicit a partial response. It all depends on what the mutations are. If a virus changes enough it may no longer be recognizable as the virus you were previously infected with. We're somewhat lucky with Covid because its structure makes it less likely to mutate to the point where we don't get some kind of response, but it's already evolved so much that our first vaccines which were 90% effective at preventing infection while at full strength are now only 30-40% effective at preventing infection. The good news so far is that even the old vaccines are pretty effective against the most severe cases and death, but that too is subject to change. It's already looking like re-exposing your immune system has diminishing returns. That was one concern people had over recommending 4th doses of the original vaccines. The protection from infection people got from shot #4 didn't last nearly as long as it did after getting shot #3. I'm really hoping the new vaccines help with that. Right now people who get covid can get reinfected with the newest strain after just one month!