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> Unlike every previous virus Have we reached "herd immunity" for syphilis? Herpes? Was smallpox eradicated via "herd immunity" that wasn't reached via a vacci

> 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.

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.