"Herd immunity occurs when a large portion of a community (the herd) becomes immune to a disease, making the spread of disease from person to person unlikely. As a result, the whole community becomes protected — not just those who are immune."
It seems that even if everyone were fully vaccinated, we still would not achieve herd immunity. We would still be passing the virus to one another, but less frequently, as people with breakthrough infections generate a smaller viral load to exhale, and for fewer days. And the infections would be relatively mild with hospitalizations and deaths much less common.
This alone is a huge improvement over pre-vaccine days. But it's not herd immunity. We'd still be seeing frequent cases of people needing to quarantine and people feeling under the weather for a few days, and the ongoing need for masking, distancing, and testing.
Here's good news. In tandem with a degree of natural immunity in the unvaccinated who acquire and survive COVID, which is likely to be most of the susceptible population given the transmissibility of the omicron strain, it seems that breakthrough infections might lead to herd immunity through development of what is now being called super immunity, or the combined immunity that comes from vaccination with that from infection. From COVID super-immunity: one of the pandemic’s great puzzles (nature.com) :
The thinking is that natural infection exposes the body to many more antigens than vaccines, which makes sense since there are so many more antigens for the immune system to see than with mRNA or attenuated vaccines. Of course, getting COVID unvaccinated followed by a vaccine is a dangerous way to achieve this super immunity, since one might not live long enough to get the vaccine.
But how about in the reverse order: breakthrough infections in the fully vaccinated? This seems much safer. Hopefully, it produces the same super immunity. It ought to, as the immune system is seeing these extra antigens, which were unfamiliar to it.
It's interesting to think of infection as a dangerous, poor man's vaccine. The result is similar: exposure to antigens resulting in the development to antibodies and a memory of them for future exposure in a degree of protection. It's not injected, of course. It is taken intranasally. And it is by far the most dangerous "vaccine" if you haven't been vaccinated by needle, but the parallel remains, and in the fully vaccinated, it may lead to super immunity, which ought to slow the transmission from person to person as more people are virus free (not experiencing breakthrough infections or spreading virus) and fewer people exposed to virus become infected. This is closer to herd immunity.
And it seems likely that the unvaccinated who get COVID and survive it will be contributing to herd immunity to some degree thanks to the intranasal "vaccine." This is probably the path humanity will take to get to something like the flu, where a vaccine is offered regularly, herd immunity is relatively high after mass vaccination, only a minority of people have the virus or feel ill at any given time, nobody is asking to see vaccine passports, masks optional, and infections are rarely severe or lethal.
This is still very speculative, and doesn't consider a new variant that can break through this super immunity, but it is encouraging. We might be six months from a situation like that just described with COVID as we already are with influenza.
And this is a counterargument that I didn't address given the length of this OP:
Analysis: How Omicron highlights fading hope of herd immunity from COVID
It seems that even if everyone were fully vaccinated, we still would not achieve herd immunity. We would still be passing the virus to one another, but less frequently, as people with breakthrough infections generate a smaller viral load to exhale, and for fewer days. And the infections would be relatively mild with hospitalizations and deaths much less common.
This alone is a huge improvement over pre-vaccine days. But it's not herd immunity. We'd still be seeing frequent cases of people needing to quarantine and people feeling under the weather for a few days, and the ongoing need for masking, distancing, and testing.
Here's good news. In tandem with a degree of natural immunity in the unvaccinated who acquire and survive COVID, which is likely to be most of the susceptible population given the transmissibility of the omicron strain, it seems that breakthrough infections might lead to herd immunity through development of what is now being called super immunity, or the combined immunity that comes from vaccination with that from infection. From COVID super-immunity: one of the pandemic’s great puzzles (nature.com) :
"Around a year ago — before Delta and other variants entered the COVID-19 lexicon — virologists Theodora Hatziioannou and Paul Bieniasz, both at the Rockefeller University in New York City, set out to make a version of a key SARS-CoV-2 protein with the ability to dodge all the infection-blocking antibodies our body makes.
"The goal was to identify the parts of spike — the protein SARS-CoV-2 uses to infect cells — that are targeted by these neutralizing antibodies in order to map a key part of our body's attack on the virus. So the researchers mixed and matched potentially concerning mutations identified in lab experiments and circulating viruses, and tested their Franken-spikes in harmless ‘pseudotype’ viruses incapable of causing COVID-19. In a study published this September in Nature1, they reported that a spike mutant containing 20 changes was fully resistant to neutralizing antibodies made by most of the people tested who had been either infected or vaccinated — but not to everyone’s. Kids and COVID: why young immune systems are still on top
"Those who had recovered from COVID-19 months before receiving their jabs harboured antibodies capable of defanging the mutant spike, which displays much more resistance to immune attack than any known naturally occurring variant. These peoples’ antibodies even blocked other types of coronaviruses. “It’s very likely they will be effective against any future variant that SARS-CoV-2 throws against them,” says Hatziioannou."
"The goal was to identify the parts of spike — the protein SARS-CoV-2 uses to infect cells — that are targeted by these neutralizing antibodies in order to map a key part of our body's attack on the virus. So the researchers mixed and matched potentially concerning mutations identified in lab experiments and circulating viruses, and tested their Franken-spikes in harmless ‘pseudotype’ viruses incapable of causing COVID-19. In a study published this September in Nature1, they reported that a spike mutant containing 20 changes was fully resistant to neutralizing antibodies made by most of the people tested who had been either infected or vaccinated — but not to everyone’s. Kids and COVID: why young immune systems are still on top
"Those who had recovered from COVID-19 months before receiving their jabs harboured antibodies capable of defanging the mutant spike, which displays much more resistance to immune attack than any known naturally occurring variant. These peoples’ antibodies even blocked other types of coronaviruses. “It’s very likely they will be effective against any future variant that SARS-CoV-2 throws against them,” says Hatziioannou."
The thinking is that natural infection exposes the body to many more antigens than vaccines, which makes sense since there are so many more antigens for the immune system to see than with mRNA or attenuated vaccines. Of course, getting COVID unvaccinated followed by a vaccine is a dangerous way to achieve this super immunity, since one might not live long enough to get the vaccine.
But how about in the reverse order: breakthrough infections in the fully vaccinated? This seems much safer. Hopefully, it produces the same super immunity. It ought to, as the immune system is seeing these extra antigens, which were unfamiliar to it.
It's interesting to think of infection as a dangerous, poor man's vaccine. The result is similar: exposure to antigens resulting in the development to antibodies and a memory of them for future exposure in a degree of protection. It's not injected, of course. It is taken intranasally. And it is by far the most dangerous "vaccine" if you haven't been vaccinated by needle, but the parallel remains, and in the fully vaccinated, it may lead to super immunity, which ought to slow the transmission from person to person as more people are virus free (not experiencing breakthrough infections or spreading virus) and fewer people exposed to virus become infected. This is closer to herd immunity.
And it seems likely that the unvaccinated who get COVID and survive it will be contributing to herd immunity to some degree thanks to the intranasal "vaccine." This is probably the path humanity will take to get to something like the flu, where a vaccine is offered regularly, herd immunity is relatively high after mass vaccination, only a minority of people have the virus or feel ill at any given time, nobody is asking to see vaccine passports, masks optional, and infections are rarely severe or lethal.
This is still very speculative, and doesn't consider a new variant that can break through this super immunity, but it is encouraging. We might be six months from a situation like that just described with COVID as we already are with influenza.
And this is a counterargument that I didn't address given the length of this OP:
Analysis: How Omicron highlights fading hope of herd immunity from COVID
