[set fair]

The expectation that we could achieve herd  immunity through vaccination was collective madness.

Who expected it? Maybe the Trumpian herd (except they didn't believe in vaccines) or the Disciples of Boris, but nobody with an ounce of common sense would believe that herd immunity could be achieved in the face of gross public ignorance and the Human Rights brigade.

Who expected it? You did

So can the vaccine give us herd immunity if enough of the population have it, or will the virus continue to circulate anyway until a vaccine-resistant mutant emerges?

Yes and yes, because herd immunity isn't the same as inherent tolerance or immunity. If 80% of the population is immune through vaccination or prior infection, the probability of anyone else being infected becomes very small (herd immunity) but those that are infected can indeed breed mutants.

[evan_au]

1 - 1/R...Herd immunity threshold

The original strain of COVID had R around 2 or 3.
1-1/R=1-1/2.5=0.6, so the WHO's target of a vaccine with > 70% efficacy would have effectively stopped spread of COVID.
Actual vaccines came in at 80% to 90% efficacy, leading some politicians and medical people to proclaim total protection of vaccination (at least that was the simplistic message presented by the press; and maybe the simplistic message understood by those politicians).

But later variants of COVID are estimated to have R around 12.
1-1/R=1-1/12=0.91, so even a 90% effective vaccine would have trouble stopping the spread, even if everyone were vaccinated.
Vaccine efficacy drops significantly with new variants, so COVID is likely to become something like flu vaccination, where they vaccinate the vulnerable against the most common circulating strains.

Smallpox, Polio...Covid

A significant difference between Smallpox/Polio and COVID is that Smallpox & Polio only infect humans. That makes it easier to control.
COVID has infected rodents, domestic pets, and deer, suggesting that there will be animal reservoirs which will continue generating new variants, even after you have vaccinated all the human population.

[alancalverd]

Who expected it? You did

Quote from: alancalverd on 24/05/2021 15:29:45
Yes and yes, because herd immunity isn't the same as inherent tolerance or immunity. If 80% of the population is immune through vaccination or prior infection, the probability of anyone else being infected becomes very small (herd immunity) but those that are infected can indeed breed mutants.

For the benefit of poor readers, I have emboldened and italicised two rather important words. The question wasn't "will it..." but "can it....."

[set fair]

Who expected it? You did

Quote from: alancalverd on 24/05/2021 15:29:45
Yes and yes, because herd immunity isn't the same as inherent tolerance or immunity. If 80% of the population is immune through vaccination or prior infection, the probability of anyone else being infected becomes very small (herd immunity) but those that are infected can indeed breed mutants.

For the benefit of poor readers, I have emboldened and italicised two rather important words. The question wasn't "will it..." but "can it....."

But the "if" had already come true by the time you made your post - 80% seropositivity by early May 2021 ( see graph on page 37 https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1101870/vaccine-surveillance-report-week-35.pdf ) , the UK reached 95% seropositivity by week 41 2021 ( last sentence page 20 https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1025358/Vaccine-surveillance-report-week-41.pdf ) and there never was herd immunity and there were no new variants in the UK between when you posted and Omicron in december. In fact in october 2021 we reached record numbers of new cases.

[alancalverd]

( see graph on page 37

and read the title and rubric. It shows that blood donors were either infected or vaccinated (Roche S assay) or infected (Roche N  assay).  As they were not a priority group for vaccination, it actually tells you nothing about vaccine takeup or effectiveness in the whole or the priority target population. Seropositivity tells you nothing about the infectivity of the subject, only that he is or has been infected or vaccinated.

Also worth questioning the validity of any extrapolation from a very self-selected group to the population as a whole. If there are roaming wolves or rampant viruses in the street, who is going to present himself in a public clinic as a blood donor for no reward? Not Joe Average,I  feel.

We also know that neither vaccination nor infection completely prevents reinfection so my "if" can only be half true - you could vaccinate everyone but that wouldn't mean that everyone was immune.

Anyway we agree that the UK population never reached an acceptable level of herd immunity.  Or have we? There are still sporadic cases but they don't make the headlines, which, as for the common cold, is probably the best working definition of herd immunity.

Epidemiology is not physics, with clear-cut numbers. At best, it's biochemistry  with complicated pathways and fractional yields, and then you have to subtract a huge dose of psychology, politics and guesswork to decide whether your intervention is effective - assuming you have defined "effective". The only credible number is excess deaths.

[Petrochemicals (OP)]

For simple models, the proportion of the population that needs to be effectively immunized (meaning not susceptible to infection) to prevent sustained spread of the infection has to be larger than 1 - 1/R This is the so-called Herd immunity threshold or herd immunity level.

This begins to sound as a retreat, but maybe it's because I'm simple. I believed what I was promised in the vaccine.

[alancalverd]

Citation needed. Who made that promise? Surely you are old enough not to believe a politician. 

[Petrochemicals (OP)]

Citation needed. Who made that promise? Surely you are old enough not to believe a politician. 

The Lancet

vaccines were shown to have 94?95% efficacy in preventing symptomatic COVID-19

https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(21)00075-X/fulltext#:~:text=vaccines%20were%20shown%20to%20have,the%20attack%20rate%20with%20placebo).

[alancalverd]

That's an experimental finding, not a promise.

[Petrochemicals (OP)]

That's an experimental finding, not a promise.

So the politicians you have conceded did say vaccines would be herd immunity, the medical journal states the vaccines will give herd immunity, and now for one night only Sir Patrick I know everything about corona Vallance states ;

  And you?ll need very very high levels of population coverage ? 70% or more ? in order to get some degree of immunity across the whole population.

https://www.gloucestershirelive.co.uk/news/uk-world-news/total-herd-immunity-would-require-4907184

I will concede that  "some degree of immunity" may be indistinct, but if a used car salesman offered some degree of performance and the wheels fell off you may have reason to be aggrieved! At no level did the vaccines provide herd immunity as seen in measles, which if like the many corona vaccines, would see the population rife with the disease.

[Petrochemicals (OP)]

Or perhaps John Tam thank you mam is more to sir's tastes,

 

Prof Van-Tam also told the panel it would also take a considerable amount of time for any herd immunity to kick in, since a large percentage of the population would need to be vaccinated for this to happen.

https://www.itv.com/news/2020-12-02/covid-vaccine-professor-jonathan-van-tam-addresses-jab-safety-concerns-of-itv-news-panel-in-q-and-a

[alancalverd]

So the politicians you have conceded did say vaccines would be herd immunity,

Quite possibly. But this is a science chatroom. Whatever Tory politicians say or do is intended to benefit themselves and their friends, at your expense, and need not be related to any actual facts.

the medical journal states the vaccines will give herd immunity,

Citation needed, but

 

And you'll need very very high levels of population coverage ? 70% or more ? in order to get some degree of immunity across the whole population.

is obvious. In the case of COVID, probably 90%, maintained for a couple of years.

[Petrochemicals (OP)]

Citation needed, but

we would expect 50 cases (99?95% of the population is disease-free, at least for 3 months).

It's not exactly what happened in new Zealand.

In the case of COVID, probably 90%, maintained for a couple of years.

You are probably thinking about eradication? As in small pox? There is no herd immunity presently from small pox in the populace. Which is why it is so perilous if a source emerged.

[Petrochemicals (OP)]

But yes, as the quotes espouse, herd immunity was supposed to be imbued to the populace.

[alancalverd]

But yes, as the quotes espouse, herd immunity was supposed to be imbued to the populace.

Supposed by whom? No scientist would make such a statement without lots of qualification (as Vallance and Van Tam stated) and so far you haven't even quoted a professional liar as making such a promise. It seems to be a figment of your imagination.

[Petrochemicals (OP)]

But yes, as the quotes espouse, herd immunity was supposed to be imbued to the populace.

Supposed by whom? No scientist would make such a statement without lots of qualification (as Vallance and Van Tam stated) and so far you haven't even quoted a professional liar as making such a promise. It seems to be a figment of your imagination.

You must be winding me up. There is the already quoted

And you'll need very very high levels of population coverage ? 70% or more ? in order to get some degree of immunity across the whole population

And then the WHO, not the 60s band either!

https://www.who.int/news-room/questions-and-answers/item/herd-immunity-lockdowns-and-covid-19

Herd immunity against COVID-19 should be achieved by protecting people through vaccination

So there you are! Herd immunity vaccination. Didn't work, new Zealand tried it, Brazil now has a lower mortality rate than the UK, even though the ethnic make up is more vulnerable.

Screenshot_20230614_234924.jpg (253.25 kB . 1920x1200 - viewed 648 times)

[alancalverd]

You seem unable to distinguish between "should....if....." and a promise.

I could drive to Edinburgh without stopping if the road is clear and I have a full tank of fuel. So I set off with half a gallon of petrochemicals on a snowy day, and when we grind to a halt at Peterborough you complain "but you promised....."

I would understand your attitude if English were not your native language, or you were 8 years old, but I doubt that you meet those criteria. Oh, sorry, I mentioned criteria, which is a rude word.

[Petrochemicals (OP)]

You seem unable to distinguish between "should....if....." and a promise.

I could drive to Edinburgh without stopping if the road is clear and I have a full tank of fuel. So I set off with half a gallon of petrochemicals on a snowy day, and when we grind to a halt at Peterborough you complain "but you promised....."

I would understand your attitude if English were not your native language, or you were 8 years old, but I doubt that you meet those criteria. Oh, sorry, I mentioned criteria, which is a rude word.

You would make a very good politician, possibly tory, you may have been able to help out johnson. Or used car salesman.

The who is espousing the vaccination programme to provide herd immunity. What you are trying to make a case for is "that every body should bare in mind it may not work", a post climax disclaimer!

[alancalverd]

The who is espousing the vaccination programme to provide herd immunity.

Citation needed. WHO certainly promote vaccination for disease prevention, and has been very successful in doing so. But they are not so stupid  as to suggest that you can achieve herd immunity in a short time with an inadequate uptake, a short period of effectiveness, and a rapidly evolving virus. Nor that herd immunity means 100% immunity of the entire herd.They know what it means even if you don't.

Did Loathsome Johnson ever make such a promise?

[Petrochemicals (OP)]

The who is espousing the vaccination programme to provide herd immunity.

Citation needed. WHO certainly promote vaccination for disease prevention, and has been very successful in doing so. But they are not so stupid  as to suggest that you can achieve herd immunity in a short time with an inadequate uptake, a short period of effectiveness, and a rapidly evolving virus. Nor that herd immunity means 100% immunity of the entire herd.They know what it means even if you don't.
?

So the WHO are saying herd immunity? That is in fact proof of my point.

I. adequate uptake in New Zealand? I will grant you that the period of effectiveness is not long enough, ie nil.

I have given you the Who link. I have shown you the quote. There is no more I can do.