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General => The Stay Safe Board => Topic started by: zetlander on Thursday 15 October 20 22:30 BST (UK)

Title: Herd Immunity
Post by: zetlander on Thursday 15 October 20 22:30 BST (UK)
Keep hearing this expression - surely the only time we may get 'herd immunity' is when every member of the herd has had Covid and hopefully then they are immune to the virus??
Title: Re: Herd Immunity
Post by: Rena on Thursday 15 October 20 22:52 BST (UK)
I heard a discussion today and Herd Immunity probably won't happen because it seems some people are catching the virus a second time, which indicates one of two things (or both things).  (a) the virus has mutated, or (b) immunity only lasts a short period of time.   
Title: Re: Herd Immunity
Post by: Kiltpin on Thursday 15 October 20 23:27 BST (UK)
There is also a (c) Long Covid. Where someone contracts covid, it goes through its cycle and then goes into hibernation. It then comes back (not as strongly) a while later.   

There is some debate as to whether people really get a second contraction, or have Long Covid. And if it can come back once, can it come back again and again? 

Roll on a vaccine. 

Regards 

Chas
Title: Re: Herd Immunity
Post by: BushInn1746 on Friday 16 October 20 05:39 BST (UK)
I heard a discussion today and Herd Immunity probably won't happen because it seems some people are catching the virus a second time, which indicates one of two things (or both things).  (a) the virus has mutated, or (b) immunity only lasts a short period of time.   

World Health Organisation (WHO)
Variant analysis of SARS-CoV-2 genomes
https://www.who.int/bulletin/volumes/98/7/20-253591/en/

According to WHO (in the above link, which mentions strains, mutations & variants) if you try and treat Covid-19 it mutates and can potentially become more virulent:-

"Community transmission of the virus, as well as anti-viral treatments, can engender novel mutations in the virus, potentially resulting in more virulent strains with higher mortality rates or emergence of strains resistant to treatment.15 Therefore, systematic tracking of demographic and clinical patient information, as well as strain information is indispensable to effectively combat COVID-19."

15 is a Footnote.
15. Sanjuán R, Domingo-Calap P. Mechanisms of viral mutation. Cell Mol Life Sci. 2016 12;73(23):4433–48. http://dx.doi.org/10.1007/s00018-016-2299-6 pmid: 27392606 [27392606 is a link to this ... ] http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=27392606&dopt=Abstract
 ----------
Perhaps why Scientists have already said we have got to adapt and learn to live with it?

Continue with Wash Hands, Socially Distance and Mask protection

Mark

See also research by the Quadram Institute, England
https://quadram.ac.uk/covid-19-genome-sequencing-in-norfolk-helps-manage-coronavirus-outbreaks/
Title: Re: Herd Immunity
Post by: pharmaT on Friday 16 October 20 08:51 BST (UK)
Keep hearing this expression - surely the only time we may get 'herd immunity' is when every member of the herd has had Covid and hopefully then they are immune to the virus??

For herd immunity 70-80% of the population would have to be immune, although preferably more.  That's why vaccines are generally considered the only safe way to achieve this.  As Rena says there is a good chance that any immunity is not long lasting, although it could be a situation like rubella when a proportion of the population never achieve immunity but others can.
Title: Re: Herd Immunity
Post by: trystan on Friday 16 October 20 09:07 BST (UK)
The thing is, we now live in a "world population", not just in our own country in a sense. There is so much free movement of people that effectively the herd immunity would have to be the world's population? Or I may have misunderstood it.
Title: Re: Herd Immunity
Post by: BushInn1746 on Friday 16 October 20 09:11 BST (UK)
The Lancet

Google Summary
3 days ago — SARS-CoV-2=severe acute respiratory syndrome coronavirus 2. This case report adds to rapidly growing evidence of COVID-19 reinfection, in which viral genomic sequences were used to confirm infections by distinct isolates of SARS-CoV-2.

https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30783-0/fulltext

Added:

"Thus, reinfection cases tell us that we cannot rely on immunity acquired by natural infection to confer herd immunity; not only is this strategy lethal for many but also it is not effective."
Title: Re: Herd Immunity
Post by: pharmaT on Friday 16 October 20 09:13 BST (UK)
The thing is, we now live in a "world population", not just in our own country in a sense. There is so much free movement of people that effectively the herd immunity would have to be the world's population? Or I may have misunderstood it.

Within our country and those most likely to travel here.  Yes I'd have thought so
Title: Re: Herd Immunity
Post by: Guy Etchells on Friday 16 October 20 09:39 BST (UK)
The thing is, we now live in a "world population", not just in our own country in a sense. There is so much free movement of people that effectively the herd immunity would have to be the world's population? Or I may have misunderstood it.

If you are thinking of getting rid of the virus completely you are correct, for most countries herd immunity is a step towards controlling a disease, i.e. keeping the spread limited to controllable levels.
In which case a countrywide immunisation programme suffices.
This does not wipe out the virus or disease but reduces the numbers liable to require intensive care.
An additional benefit of vaccination is it often gives a longer lasting immunity than catching and recovering from the virus/disease does.
Cheers
Guy
Title: Re: Herd Immunity
Post by: BushInn1746 on Friday 16 October 20 09:41 BST (UK)

The Lancet 12th October 2020

https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30783-0/fulltext

"Thus, reinfection cases tell us that we cannot rely on immunity acquired by natural infection to confer herd immunity; not only is this strategy lethal for many but also it is not effective."
Title: Re: Herd Immunity
Post by: Guy Etchells on Friday 16 October 20 10:03 BST (UK)

The Lancet 12th October 2020

https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30783-0/fulltext

"Thus, reinfection cases tell us that we cannot rely on immunity acquired by natural infection to confer herd immunity; not only is this strategy lethal for many but also it is not effective."

Very selective quoting, missing out the opinion "For now, one vaccine will be sufficient to confer protection against all circulating variants." and possibly more importantly "Herd immunity requires safe and effective vaccines and robust vaccination implementation."
In other words the research shows vaccines work and protect but natural transmission of the virus may not trigger enough reaction in the body to create an immune response.
Cheers
Guy
Title: Re: Herd Immunity
Post by: BushInn1746 on Friday 16 October 20 12:19 BST (UK)

The Lancet 12th October 2020

https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30783-0/fulltext

"Thus, reinfection cases tell us that we cannot rely on immunity acquired by natural infection to confer herd immunity; not only is this strategy lethal for many but also it is not effective."

Very selective quoting, missing out the opinion "For now, one vaccine will be sufficient to confer protection against all circulating variants." and possibly more importantly "Herd immunity requires safe and effective vaccines and robust vaccination implementation."
In other words the research shows vaccines work and protect but natural transmission of the virus may not trigger enough reaction in the body to create an immune response.
Cheers
Guy

Around the 3rd week of September 2020 those on the vaccine trial in England were just about to be exposed to Covid-19. Vaccine development here is ongoing.

Tested with Healthy Volunteers

"Phases one and two of the clinical trial took place simultaneously in April in southern England, when safety and immune responses were checked in more than a thousand healthy volunteers ages 18 to 55."
https://www.nationalgeographic.co.uk/science-and-technology/2020/07/oxford-vaccine-enters-final-phase-of-covid-19-trials-heres-what

"Participants must NOT: Have tested positive for COVID-19, be pregnant, intending to become pregnant, or breastfeeding during the study, or have previously taken part in a trial with an adenoviral vaccine or received any other coronavirus vaccines."
https://www.ox.ac.uk/news/2020-04-23-oxford-covid-19-vaccine-begins-human-trial-stage

"The purpose of this study is to test a new vaccine against COVID-19 in healthy volunteers."
https://www.ox.ac.uk/news/2020-05-22-oxford-covid-19-vaccine-begin-phase-iiiii-human-trials
Title: Re: Herd Immunity
Post by: Maiden Stone on Friday 16 October 20 15:44 BST (UK)
For herd immunity 70-80% of the population would have to be immune, although preferably more.  That's why vaccines are generally considered the only safe way to achieve this.  As Rena says there is a good chance that any immunity is not long lasting, although it could be a situation like rubella when a proportion of the population never achieve immunity but others can.

The minority of people opposed to vaccination of children for infectious diseases like rubella can only safely make that choice when herd immunity exists due to the vast majority of parents getting their children vaccinated. Herd immunity is at risk if that minority grows. 
Title: Re: Herd Immunity
Post by: Kiltpin on Friday 16 October 20 16:06 BST (UK)
For reasons which are not completely understood, there is a very large anti-vax movement in Italy. So much so that the Government was worried about the health of the children in state schools. 

So with no fanfare nor forewarning they passed a law requiring all children in state schools to be up to date with their immunisations. Parents were given 28 days (I think) to register the certificates with the school and get vaccinations that were needed. 

Those who missed the deadline were excluded from school till they either got vaccinated, or were registered in a private (expensive) school. 

Parents were given the freedom of choice. If they truly believed in the anti-vax movement, they could remove their children and pay. 

An elegant compromise I think. 

Regards 

Chas
Title: Re: Herd Immunity
Post by: Rena on Friday 16 October 20 18:48 BST (UK)
There is also a (c) Long Covid. Where someone contracts covid, it goes through its cycle and then goes into hibernation. It then comes back (not as strongly) a while later.   

Roll on a vaccine. 

Regards 

Chas

That's what used to regularly happen to my late OH and many thousands of men.   When he was in HM forces in the 1950s he and his mates in the middle east caught a virulent strain of malaria and even thirty years later would still have days of weakness, shivering in bed.  Luckily a p;ill emerged to cure the "long malaria"
Title: Re: Herd Immunity
Post by: Llwyd on Friday 16 October 20 19:20 BST (UK)
In 1945 my dad, prior to being despatched to Norway to help deal with German POWs, declined to have his vaccinations. This fact is recorded on his military record, in all at least four places.
Let's hope a vaccination is not too far off, even one which will at the very least mitigate the most severe effects of this virus.
 :)
Title: Re: Herd Immunity
Post by: DianaCanada on Saturday 17 October 20 14:00 BST (UK)
There has been studies on the connection of the BCG vaccinations against TB helping fight Covid-19 in people who are exposed to it.  This refers to those who were vaccinated in the past. I felt good as I read that, as I had them as a child, and if memory serves, a booster as a teen.  Unfortunately I then read that blood type A are more susceptible...my type 😒.
Time will tell what all this means, interesting to see what scientists will conclude in 5 or 10 years.
Title: Re: Herd Immunity
Post by: Guy Etchells on Saturday 17 October 20 14:26 BST (UK)
There has been studies on the connection of the BCG vaccinations against TB helping fight Covid-19 in people who are exposed to it.  This refers to those who were vaccinated in the past. I felt good as I read that, as I had them as a child, and if memory serves, a booster as a teen.  Unfortunately I then read that blood type A are more susceptible...my type 😒.
Time will tell what all this means, interesting to see what scientists will conclude in 5 or 10 years.

It seems the BCG vaccine shows good results for those vaccinated early in life (infants) rather than those vaccinated around 11 to teens (UK children), these seem to have missed the optimal time.
If you were vaccinated in Canada early in life you may have some protection against the worst effects of covid. There is still research being carried out on this.
Cheers
Guy
Title: Re: Herd Immunity
Post by: DianaCanada on Saturday 17 October 20 15:17 BST (UK)
I think I had it as an infant and again in grade 1, age 6.  We all lined up before going to the school library and we all dreaded it.  It hurt like the dickens, scratched along the lower back.  Other needles don’t bother me, but those sure did.
Title: Re: Herd Immunity
Post by: BushInn1746 on Saturday 17 October 20 17:31 BST (UK)
There has been studies on the connection of the BCG vaccinations against TB helping fight Covid-19 in people who are exposed to it.  This refers to those who were vaccinated in the past. I felt good as I read that, as I had them as a child, and if memory serves, a booster as a teen.  Unfortunately I then read that blood type A are more susceptible...my type 😒.
Time will tell what all this means, interesting to see what scientists will conclude in 5 or 10 years.

It seems the BCG vaccine shows good results for those vaccinated early in life (infants) rather than those vaccinated around 11 to teens (UK children), these seem to have missed the optimal time.
If you were vaccinated in Canada early in life you may have some protection against the worst effects of covid. There is still research being carried out on this.
Cheers
Guy

Thanks Guy,

Jolly good I had this BCG / TB injection at High School it was given in my shoulder/arm end, it felt bruised for years and I had a large raised spot which remained for decades and can still see where I was injected.

First we were jabbed with a multi-pronged jab to see if we had a reaction or not, but decided I needed the main TB injection.

I told my Mother I'd have the TB jab (she signed), because I'd had Chronic Bronchitis many years running as a child. The non-stop repetitive Bronchitis Cough use to make the throat and respiratory system sore and painful, often tasting blood.

I'd only fall asleep each night when severe exhaustion from non-stop coughing, set in.

I had a vapor burner too, now outlawed apparently.

My Mother (in her 80s now) sat by my bedside as a child all night at home and the Family Doctor came twice a day and listened to my chest and back to try and check for possible pneumonia and sometimes prescribed penicillin. He said I'd grow out of it and as the years past, I did.
 ----------
I've just had something like my old Bronchitis in December 2019 which reoccurred over January/February 2020 and my health has been to hell & back this Spring.

Mark
Title: Re: Herd Immunity
Post by: DianaCanada on Saturday 17 October 20 18:10 BST (UK)
Mark, sorry to hear about your health issues.  Hope you see some improvement soon!
I had bronchitis around the time I had the BCG probably the previous year. It was still on the back (early 70’s) and they measured the raised bump afterward and promptly sent me off for an X-ray as the bump was larger than it should have been. Their conclusion was that the TB was either in my system or I simply overreacted to the vaccine.  I had one other bronchitis bout when I was 40, in the summer after my mother died. Funnily enough, I got quite ill both times after my parents died, am convinced they were connected.
Title: Re: Herd Immunity
Post by: Top-of-the-hill on Saturday 17 October 20 20:45 BST (UK)
  "There is also a (c) Long Covid. Where someone contracts covid, it goes through its cycle and then goes into hibernation. It then comes back (not as strongly) a while later."

   This is not my understanding of long covid, though admittedly my understanding of any of this is not great. My daughter had the bug in March, and has had relapses since. When she had the first and worst relapse, she had a test which was negative.
Title: Re: Herd Immunity
Post by: Flattybasher9 on Wednesday 18 November 20 09:46 GMT (UK)
Interesting bit on the news yesterday. They were discussing the 2 (so far, Pfizer and Moderna) promising vaccines. The CEO of Moderna was on talking about their vaccine. He stated that the UK has ordered circa 5 million doses of the vaccine, and that they will be ready late March 2021 at a cost of £25.00 per vaccine. The newscaster asked why the high price, considering that Pfizer’s version is only £4.00 per vaccine. He said that it was the cost of research and production. So it seems that the country has purchased circa 5 million dosed costing circa £125,000,000 compared circa £20,000,000.
I have to wonder, will I be on the primary list?

Malky.
Title: Re: Herd Immunity
Post by: Skoosh on Wednesday 18 November 20 14:08 GMT (UK)
Asda here have the flu-jag for £8, most chemists about £12.

Skoosh.