DCAggie13y said:
74% of people over the age of 5 have been vaccinated.
You have to think at least 33% of the unvaccinated have prior infection which puts us around 90% vaccinated or previously infected.
All this talk about the unvaccinated, you couldn't get 82% of adults to eat free ice cream. The population of unvaccinated with no prior infection can't be so large that it's the root of all problems in the US.
Is it leaky vaccines? Or is the unboosted that are the problem?
Herd immunity isn't going to happen unless the immunity lasts for significant time. Even then, it would be tough since there is always the possibility for new outbreaks to pop up since it is a zoonosis.
The concept of herd immunity comes from veterinary science and herds of animals in which you have a group of animals kept together and apart from other animals of their kind. For that kind of herd immunity in humans, it would just about take living in a very isolated population like maybe on a distant, nearly impossible to reach island that doesn't get visitors.
So in regards to humans, the meaning has been changed a bit.
The following is from a ProMED post on October 21, 2020:
Quote:
The original context of recognising the phenomenon of herd immunity was outbreaks of contagious infection in herds of cattle. A herd consisted of a finite number of heads of cattle, free-roaming in the farmer's land, without contact with other cattle. If nothing was done, many would get infected and some would die -- but eventually, the outbreak itself would die out, sparing others that never got infected. Animals that recovered from infection were typically immune but the uninfected ones lacked this immunity.
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Second: a 'herd' refers to a group of animals that have no contact with other animals. So, the condition of herd immunity required no in-migration of fresh animals during an outbreak, so that there is no external source of infection in addition to the intra-herd source.
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Herd immunity in the human context is defined differently by 2 schools of vaccinologists. The traditionalists maintain that herd immunity was the theoretical possibility of interrupting transmission when a majority was infected and became immune. There has never been a real-life situation of herd immunity interrupting contagious infection in open societies. In island populations without in-migration, outbreaks have died out until they were reintroduced later.
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Herd immunity conditions in herds of cattle cannot apply in human communities.
Practical vaccinologists define herd immunity as the fraction of people immune in the community -- a simple way to measure the immunity profile of a community. We might as well call it 'community immunity'.
I can only think of one viral disease affecting humans that has been eradicated -- smallpox.
In spite of massive efforts against other viral diseases such as polio and measles, both are still around in parts of the world.
And rabies, in which nearly all human cases arise from contact with animals, is rampant through much of the world with tens of thousands of human deaths per year.
