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> Manaus shows that pursuing herd immunity through natural infection is not a guarantee. Not a guarantee of what? Are we suggesting that we have a virus here t

by cheph 6y ago

> Manaus shows that pursuing herd immunity through natural infection is not a guarantee. Not a guarantee of what? Are we suggesting that we have a virus here that, unlike every previous virus, we can only reach herd immunity for with a vaccine?

reissbaker 6y ago
> Unlike every previous virus Have we reached "herd immunity" for syphilis? Herpes? Was smallpox eradicated via "herd immunity" that wasn't reached via a vaccine? Polio? It is extremely common for viruses to not be eradicated unless there is a vaccine. Even vaccines are not guaranteed to be enough, e.g. with most influenza strains, although flu vaccines have managed to keep the death toll low enough for us to move on with our lives.
- timr 6y ago
  > Have we reached "herd immunity" for syphilis? Syphilis is a bacterial infection. You can get it more than once. There is no such thing as herd immunity. > Herpes? ...is transmitted via intimate, direct contact. You don't get herpes by walking into a crowded room, and there's no way to be "immune" to herpes without also being a carrier. Herd immunity isn't a relevant concept. > Was smallpox eradicated via "herd immunity" that wasn't reached via a vaccine? Smallpox was eradicated by herd immunity that was achieved via a mixture of natural and vaccine-induced immunity. Initially, a large portion of the population was immune due to natural infection. Over time, vaccinations were targeted to local outbreaks. > Polio? We have not eradicated polio. In some (now 3) countries, polio is endemic, and outbreaks are self-regulated by herd immunity. Herd immunity does not mean that a disease is eliminated. It means that the spread of the disease is naturally controlled.
  - ganafagol 6y ago
    > Herd immunity does not mean that a disease is eliminated. It means that the spread of the disease is naturally controlled. Not necessarily "naturally".
    - timr 6y ago
      I mean "naturally", in the sense that it is a process mediated by the immune system. Even a vaccine-induced immune response is natural. But yes, my choice of words is confusing there. The point I am making is that herd immunity is not eradication. People (like the OP) confuse the two concepts. You can have herd immunity in a population, and the pathogen will still circulate. Observing that a virus still infects people is not evidence that herd immunity to that virus has not been achieved.
  - reissbaker 6y ago
    > Syphilis is a bacterial infection "Herd immunity" applies to bacterial infections as it does to viral. All it means is that the R-value is low enough that the disease doesn't spread. https://en.wikipedia.org/wiki/Herd_immunity#Theoretical_basis https://en.wikipedia.org/wiki/Herd_immunity#Theoretical_basi... As an example, pertussis is a bacterial infection which most US communities have herd immunity to thanks to the pertussis vaccine. > You can get it more than once. There are also viral infections you can get more than once. In fact, the South African variant of COVID is likely possible to get even if you've had COVID before. > Mixture of natural and vaccine-induced immunity. Sure, just like nearly every virus that has been eliminated via vaccine. As, hopefully, COVID will be. Smallpox was not eradicated without a vaccine. > We have not eradicated polio The vast majority of the world has indeed eradicated polio via vaccination, as made clear by the fact that only three countries out of 195 still have a polio problem. The same is true for measles, rubella, and a variety of other diseases, none of which would have been eradicated from most populations without vaccines. The OP's stance that COVID would be somehow unique amongst viruses or diseases if it needed a vaccine for eradication ignores the history of every disease for which we've mass-vaccinated against in the 20th century, as well as the vast majority of diseases that have not been and never will be eradicated by herd-immunity-reached-through-mass-infection.
    - timr 6y ago
      "Herd immunity" applies to bacterial infections as it does to viral. It does not apply to Syphilis. Getting an infection today does not prevent me from getting one next month. Even if it did, it doesn't materially affect the rate at which other people get it from me...unless we are rutting like rabbits in some constant random orgy.
roelschroeven 6y ago
For what viruses have we reached meaningful herd immunity without vaccines?
- standardUser 6y ago
  Zika is one.
- maxerickson 6y ago
  Flu, if you grant that different strains count.
  - acdha 6y ago
    Influenza? The one which kills thousands of people every year despite widespread vaccination?
    - maxerickson 6y ago
      Why would you respond like this without accounting for the rest of my very short comment?
      - acdha 6y ago
        Because it shows that herd immunity is not a given. Influenza is not only not there but will never be due to the nature of the virus being unusually prone to mutating.
        maxerickson 6y ago
        That doesn't address what I said. There is an argument to be made that various strains are different viruses, and that we have herd immunity to some of them. It wouldn't make sense to invent an English name for each one, but that doesn't mean they should be treated as a single thing in all contexts. And I even stated it as ambiguous depending on how you count strains, I'm not arguing that there is only one way to look at it!
statstutor 6y ago
I don't believe there is any named virus where we have reached herd immunity without a vaccine. Herd immunity was defined by the theory that it would prevent the spread of measles. It only did so with any measurable effect after universal vaccination was introduced.
- standardUser 6y ago
  Zika is presumed to have receded due to natural herd immunity.
  - statstutor 6y ago
    That's possible but isn't mentioned on its wikipedia article - mosquito control seems at least as relevant.

by cheph 6y ago

reissbaker 6y ago

> Unlike every previous virus Have we reached "herd immunity" for syphilis? Herpes? Was smallpox eradicated via "herd immunity" that wasn't reached via a vaccine? Polio? It is extremely common for viruses to not be eradicated unless there is a vaccine. Even vaccines are not guaranteed to be enough, e.g. with most influenza strains, although flu vaccines have managed to keep the death toll low enough for us to move on with our lives.

timr 6y ago
> Have we reached "herd immunity" for syphilis? Syphilis is a bacterial infection. You can get it more than once. There is no such thing as herd immunity. > Herpes? ...is transmitted via intimate, direct contact. You don't get herpes by walking into a crowded room, and there's no way to be "immune" to herpes without also being a carrier. Herd immunity isn't a relevant concept. > Was smallpox eradicated via "herd immunity" that wasn't reached via a vaccine? Smallpox was eradicated by herd immunity that was achieved via a mixture of natural and vaccine-induced immunity. Initially, a large portion of the population was immune due to natural infection. Over time, vaccinations were targeted to local outbreaks. > Polio? We have not eradicated polio. In some (now 3) countries, polio is endemic, and outbreaks are self-regulated by herd immunity. Herd immunity does not mean that a disease is eliminated. It means that the spread of the disease is naturally controlled.
- ganafagol 6y ago
  > Herd immunity does not mean that a disease is eliminated. It means that the spread of the disease is naturally controlled. Not necessarily "naturally".
  - timr 6y ago
    I mean "naturally", in the sense that it is a process mediated by the immune system. Even a vaccine-induced immune response is natural. But yes, my choice of words is confusing there. The point I am making is that herd immunity is not eradication. People (like the OP) confuse the two concepts. You can have herd immunity in a population, and the pathogen will still circulate. Observing that a virus still infects people is not evidence that herd immunity to that virus has not been achieved.
- reissbaker 6y ago
  > Syphilis is a bacterial infection "Herd immunity" applies to bacterial infections as it does to viral. All it means is that the R-value is low enough that the disease doesn't spread. https://en.wikipedia.org/wiki/Herd_immunity#Theoretical_basis https://en.wikipedia.org/wiki/Herd_immunity#Theoretical_basi... As an example, pertussis is a bacterial infection which most US communities have herd immunity to thanks to the pertussis vaccine. > You can get it more than once. There are also viral infections you can get more than once. In fact, the South African variant of COVID is likely possible to get even if you've had COVID before. > Mixture of natural and vaccine-induced immunity. Sure, just like nearly every virus that has been eliminated via vaccine. As, hopefully, COVID will be. Smallpox was not eradicated without a vaccine. > We have not eradicated polio The vast majority of the world has indeed eradicated polio via vaccination, as made clear by the fact that only three countries out of 195 still have a polio problem. The same is true for measles, rubella, and a variety of other diseases, none of which would have been eradicated from most populations without vaccines. The OP's stance that COVID would be somehow unique amongst viruses or diseases if it needed a vaccine for eradication ignores the history of every disease for which we've mass-vaccinated against in the 20th century, as well as the vast majority of diseases that have not been and never will be eradicated by herd-immunity-reached-through-mass-infection.
  - timr 6y ago
    "Herd immunity" applies to bacterial infections as it does to viral. It does not apply to Syphilis. Getting an infection today does not prevent me from getting one next month. Even if it did, it doesn't materially affect the rate at which other people get it from me...unless we are rutting like rabbits in some constant random orgy.

roelschroeven 6y ago

For what viruses have we reached meaningful herd immunity without vaccines?

standardUser 6y ago
Zika is one.
maxerickson 6y ago
Flu, if you grant that different strains count.
- acdha 6y ago
  Influenza? The one which kills thousands of people every year despite widespread vaccination?
  - maxerickson 6y ago
    Why would you respond like this without accounting for the rest of my very short comment?
    - acdha 6y ago
      Because it shows that herd immunity is not a given. Influenza is not only not there but will never be due to the nature of the virus being unusually prone to mutating.
      - maxerickson 6y ago
        That doesn't address what I said. There is an argument to be made that various strains are different viruses, and that we have herd immunity to some of them. It wouldn't make sense to invent an English name for each one, but that doesn't mean they should be treated as a single thing in all contexts. And I even stated it as ambiguous depending on how you count strains, I'm not arguing that there is only one way to look at it!

statstutor 6y ago

I don't believe there is any named virus where we have reached herd immunity without a vaccine. Herd immunity was defined by the theory that it would prevent the spread of measles. It only did so with any measurable effect after universal vaccination was introduced.

standardUser 6y ago
Zika is presumed to have receded due to natural herd immunity.
- statstutor 6y ago
  That's possible but isn't mentioned on its wikipedia article - mosquito control seems at least as relevant.