Coronavirus

[Aruntraveller]

Spud

"Yes, I meant that people with good innate immunity were not exposed to the wild type. If they had been, their innate, non-specific antibodies would have neutralized not only the wild type but also mutated strains, which would then only be able to circulate in low levels. Since this didn't happen, more infectious variants were able to become dominant, causing a higher infectious pressure, which the innate immunity of healthy people finds harder to deal with."

This is bollocks. Coronaviruses mutate. Natural immunity also drives mutations.

People died at the beginning of the pandemic from the original strain in Wuhan who were healthy, stop stretching for reasons to justify your, quite frankly, ludicrous aversion to vaccination programmes.

I really am not sure what your point is.

If we had allowed Covid to carry on in it's own way with no interventions, many many more people would have died.

If we had interventions such as social distancing, face masks etc, still many many more people would have died. There are also all the other negative consequences that go with such a policy both economically and psychologically.

The ONLY way out of this situation that gets us anywhere close to normal is vaccination.

To do nothing would be at the very least manslaughter.

Please step forward one Alexander Boris de Pfeffel Johnson, the do-nothinger par excellence.

[Udayana]

Sure - but I'm also talking about what the person in the Spanish researchers' article in Udayana's link says, that "the absence of circulation of certain pathogens can lead to a decrease in herd immunity against them. This can promote the rise of more serious, longer-lasting epidemics that start sooner".
I wondered whether "certain pathogens" includes Covid 19.

In basic epidemiological models the population falls into three groups:

Susceptible - individuals who can be infected by the disease

Infected - individuals who are infected and can spread the infection

Removed - individuals that are no longer relevant because:

 a) they are naturally immune
 b) they have been infected but recovered with at least temporary immunity
 c) they have been vaccinated
 d) they have been infected and died

The herd immunity threshold is the proportion of the population that must be in the Removed group to bring the number of susceptible individuals infected by contact with each infected individual to 1 or less, such that the epidemic ends.

For both flu and covid we are not going to get to the herd immunity threshold as new variants arise quickly, so everyone will eventually end up in one of the Removed sub-groups.

We can take our chances but clearly the best bet is to be vaccinated even given the vaccination is not perfect.

[Aruntraveller]

Strong stuff from Marina Hyde:

https://www.theguardian.com/commentisfree/2021/oct/12/covid-report-government-boris-johnson-scientific-advisers-polls

[Spud]

In basic epidemiological models the population falls into three groups:

Susceptible - individuals who can be infected by the disease

Infected - individuals who are infected and can spread the infection

Removed - individuals that are no longer relevant because:

 a) they are naturally immune
 b) they have been infected but recovered with at least temporary immunity
 c) they have been vaccinated
 d) they have been infected and died

The herd immunity threshold is the proportion of the population that must be in the Removed group to bring the number of susceptible individuals infected by contact with each infected individual to 1 or less, such that the epidemic ends.

For both flu and covid we are not going to get to the herd immunity threshold as new variants arise quickly, so everyone will eventually end up in one of the Removed sub-groups.

We can take our chances but clearly the best bet is to be vaccinated even given the vaccination is not perfect.

I don't think your explanation  takes into account the people from the susceptible group who can be infected but can recover without developing long-term acquired immunity - ie those whose innate antibodies neitralize the virus.

As long as a low infection rate is maintained, thia group helps protect those who are susceptible to severe morbidity and mortality.

[Nearly Sane]

Indeed

[Udayana]

I don't think your explanation  takes into account the people from the susceptible group who can be infected but can recover without developing long-term acquired immunity - ie those whose innate antibodies neitralize the virus.

As long as a low infection rate is maintained, thia group helps protect those who are susceptible to severe morbidity and mortality.

That would be most people: they are susceptible, if infected they can further spread the infection but have some, often temporary, level of immunity when recovered.  How can they possibly be helping protect anyone except by getting vaccinated so they reduce the likelihood of spreading the disease? 
 

[Spud]

That would be most people: they are susceptible, if infected they can further spread the infection but have some, often temporary, level of immunity when recovered.  How can they possibly be helping protect anyone except by getting vaccinated so they reduce the likelihood of spreading the disease?

I mean those who have not been previously exposed but can still recover while specific antibodies are not present in high enough amounts to play a part in the recovery. Such as most young children and asymptomatically infected people. IIRC these do not shed as much virus, therefore they are less of a threat to others, and can therefore act as a sponge to soak up the virus. I thought this was the concept being described in the news - having a level of circulation of Flu that will help prevent an epidemic?

[Udayana]

I mean those who have not been previously exposed but can still recover while specific antibodies are not present in high enough amounts to play a part in the recovery. Such as most young children and asymptomatically infected people. IIRC these do not shed as much virus, therefore they are less of a threat to others, and can therefore act as a sponge to soak up the virus. I thought this was the concept being described in the news - having a level of circulation of Flu that will help prevent an epidemic?

No. The more people there are who are less likely to be infected and/or spread the infection (covid or flu or other disease) the slower the spread of the disease, but they do not act as a "sponge" - preventing the spread. They help by not participating in the spread. Of-course having the most vulnerable being vaccinated helps hugely as it reduces the chance of them getting seriously ill even if they are exposed to the virus.     

So, for example, with flu the same number of people will end up getting infected and the same number seriously ill whether or not the flu virus was circulating earlier in the year - just that cases would have been more spread out over time and, so, would be easier to deal with. Of-course if people, especially the more vulnerable, have been vaccinated with a vaccine appropriate for the variety of virus in circulation, the number of serious cases would be greatly reduced as well as the overall number of cases and speed of spread.   

[Spud]

No. The more people there are who are less likely to be infected and/or spread the infection (covid or flu or other disease) the slower the spread of the disease, but they do not act as a "sponge" - preventing the spread. They help by not participating in the spread. Of-course having the most vulnerable being vaccinated helps hugely as it reduces the chance of them getting seriously ill even if they are exposed to the virus.     

So, for example, with flu the same number of people will end up getting infected and the same number seriously ill whether or not the flu virus was circulating earlier in the year - just that cases would have been more spread out over time and, so, would be easier to deal with. Of-course if people, especially the more vulnerable, have been vaccinated with a vaccine appropriate for the variety of virus in circulation, the number of serious cases would be greatly reduced as well as the overall number of cases and speed of spread.

Okay, I am with you in that everyone being not exposed to Flu for a year and then all exposed at the same time would result in a lot of people catching it at once, thus overstretching the NHS. Simple - don't know why I didn't get that. There has already been a very bad cold which a lot of people have found difficult to shake off. Maybe this was due to the high infection rate after the summer holidays, leading to "higher likelihood of re-infection while experiencing suppression of innate antibodies by short-lived, sub-optimal antibodies acquired after initial infection" (to paraphrase Geert Vanden Bossche).

So this idea of asympomatics acting as a sponge may be talking more about innate immunity preventing dominance of more infectious variants. Since they have low specificity, these IgM-secreting memory B cells (which are already present in children prior to infection) may be able to deal equally with those variants as they do with the original strain. I need to find some research-based evidence for this, and I think there may be some on GVB's website. (But see in the above link: "Natural antibodies, mostly of IgM isotype and generated independently of previous antigen encounters, have a broad reactivity and a variable affinity." Also, The innate immune response often appears sufficient to eliminate the virus altogether, particularly in mild or asymptomatic infection.)

Specific antibodies (whether derived from infection or vaccines), if present in the population in large quantities, would drive selection of more infectious variants, since they filter out the original strain but let more infectious ones continue to circulate. So if too many people were vaccinated, you would end up with a higher rate of infection, albeit with lower morbidity/mortality, because those vaccine-derived antibodies do not prevent infection from the more infectious variants, but are effective in preventing severe disease. On the other hand, naturally acquired specific antibodies build up in lower numbers, and thus do not suppress innate IgM  so much that the latter can't prevent the more infectious variants becoming dominant.

So I wonder whether allowing this sponging effect (innate immunity of younger and fitter population preventing more infectious variants from becoming dominant) to happen in combination with vaccinating only the immunosuppressed, would lead to reduced mortality as well as reduced infection?

[Udayana]

Spud,

You seem to be concerned about which variant is dominant, but there is little we can do about that.

Variants of the Sars-Cov-2 virus are not in competition with each other. An individual can be infected by either or both. If an infected person has anti-bodies against a less infectious variant it does not make it any easier for a more infectious variant to spread ("drive infection").

In fact, it can be taken as given that the more infectious variant will dominate (ie. be seen in a larger number of cases) unless it can be kept isolated.

You might be dazzled or caught in the glare of technical jargon from an off-beam troll?   
   

[Spud]

Spud,

You seem to be concerned about which variant is dominant, but there is little we can do about that.

Variants of the Sars-Cov-2 virus are not in competition with each other. An individual can be infected by either or both. If an infected person has anti-bodies against a less infectious variant it does not make it any easier for a more infectious variant to spread ("drive infection").

In fact, it can be taken as given that the more infectious variant will dominate (ie. be seen in a larger number of cases) unless it can be kept isolated.

You might be dazzled or caught in the glare of technical jargon from an off-beam troll?   
 

His point is that if lots of people have innate antibodies that work equally well against all variants, then more infectious mutants cannot become dominant and hence the infection rate stays low.
But if those innate antibodies are suppressed by either (1) vaccine-derived ones that only work on less infectious strains or are waning, or (2) weak or waning levels of antibodies naturally acquired through previous infection, in these cases, the more infectious strains can become dominant and the infection rate will increase.
Yep he might be wrong, but he has a list of research papers that he says proves this.
Interestingly he says the vaccines are safe and effective, and is not against individuals choosing to use them; mass use, however, he says will cause the above effect and so is not advised.

[Maeght]

Spud. The talk of innate antibodies refers to children as far as I can see. At what age does that decline? Sorry if mentioned earlier.

[Udayana]

His point is that if lots of people have innate antibodies that work equally well against all variants, then more infectious mutants cannot become dominant and hence the infection rate stays low.
...

Just thinking about the first point:

Take a population of 100 people, half of whom are naturally immune against two variants, A and B. Someone with variant A passes it on to 2 others in a day (then recovers), someone with variant B passes it onto 4 people in a day before recovering. Introduce one person infected with A and one person infected with B into the population.

On day 2 there are two people infected with A but 4 people with B
On day 3 there are 4 people with A but 16 with B
...
and so on ... until all the 50 susceptible people have been infected - the next day.

You can play with the numbers but for large populations variant B will almost always be dominant - at least until we approach herd immunity. And we can see that that has been the case worldwide in populations that have had low numbers vaccinated.

[Nearly Sane]

Over a fifth of the daily world figures are in the UK

[jeremyp]

Over a fifth of the daily world figures are in the UK

Could be worse. The USA has had about 2,000 people dying every day for the last few weeks. That would be the same as about 400 people dying per day in the UK.

[Spud]

Just thinking about the first point:

Take a population of 100 people, half of whom are naturally immune against two variants, A and B. Someone with variant A passes it on to 2 others in a day (then recovers), someone with variant B passes it onto 4 people in a day before recovering. Introduce one person infected with A and one person infected with B into the population.

On day 2 there are two people infected with A but 4 people with B
On day 3 there are 4 people with A but 16 with B
...
and so on ... until all the 50 susceptible people have been infected - the next day.

You can play with the numbers but for large populations variant B will almost always be dominant - at least until we approach herd immunity. And we can see that that has been the case worldwide in populations that have had low numbers vaccinated.

Okay, fair point if we are thinking of variants that have already started spreading. If we start with the Wuhan type, though, and think about a person who has just been infected with it. When the virus starts to replicate, by chance it mutates into particles that can enter cells slightly more easily. There will be a small amount of this variant and relatively more original strain in that one person. If his non-specific, innate antibodies reduce the overall amount of virus by 90% (before S-specific antibodies are produced to clear the rest), and deal with the variant and wild type alike, there will be the same proportion of the two strains left over, so the amount of mutated virus won't be enough, if transmitted to a person with functioning innate antibodies, to become dominant. If there is a high enough proportion of people with functioning innate antibodies in the population the variant won't be able to become dominant.

This is explained from 34:18 to 48:10 in this video.

It assumes that the mutated viral particles aren't transmitted as soon as they appear in the host, whose innate immune system has rapidly been activated.

Spud. The talk of innate antibodies refers to children as far as I can see. At what age does that decline? Sorry if mentioned earlier.

They are present throughout life but decline with age.

[ProfessorDavey]

If his non-specific, innate antibodies reduce the overall amount of virus by 90% (before S-specific antibodies are produced to clear the rest), and deal with the variant and wild type alike, there will be the same proportion of the two strains left over, so the amount of mutated virus won't be enough, if transmitted to a person with functioning innate antibodies, to become dominant. If there is a high enough proportion of people with functioning innate antibodies in the population the variant won't be able to become dominant.

Completely scientifically illiterate non-sense.

Firstly that wouldn't prevent the new more transmissible variant from becoming dominant as the whole point is that for any given amount of viral load the more transmissible variant will have a greater propensity to infect and replicate within the cells of the host and be released to infect others. So you might start with equal proportions but once this goes through the next host you will have greater proportions of the new more transmissible variant, and that effect will compound with each infection, replication within a host and release cycle. Hence you get the new strain becoming dominant.

But it also fails to recognise that the innate and acquired immune systems go hand in hand - if we become infected both will become involved in the immune response. But of course the innate system alone is simply insufficient to deal with any significant infection event and even with the first exposure to the virus the combination of innate and acquired may be insufficient to prevent severe disease or even death. The key point about acquired immunity is it makes you much less vulnerable the second (third etc) time you encounter the pathogen. So we can allow this to happen naturally, and accept major levels of serious disease and death, or we can short circuit the reponse by kick start acquired immunity in a safe manner using the vaccine, so that when that person encounters the actual pathogen the are less infectious and less likely to get serious disease or die.

[Walt Zingmatilder]

That Arsehole Justin Welby should be calling down God's judgment on our Covid Loving Government but no. He's more Garden of Eton than Garden of Eden.

[ProfessorDavey]

That Arsehole Justin Welby should be calling down God's judgment on our Covid Loving Government but no. He's more Garden of Eton than Garden of Eden.

What rattled your cage on this one Vlad - this comment seems to come without any context. What exactly has Welby said in relation to covid.

I'd certainly agree that religions, and in particular the major christian denominations have been notable by their absence throughout the pandemic. While local communities, businesses, all sorts of charities, key workers etc etc have all stepped up to the plate to help others, churches have been effectively invisible.

[Gordon]

Looking at the BBC news this morning I'm struggling to understand why reintroducing the requirement to use facemasks is such a hot potato: after all, it isn't exact an onerous demand.

Here in Scotland the need to wear them in shops and public transport, and for older kids in secondary school, was never removed - and, anecdotally, compliance with this seems almost universal in my experience. 

[Nearly Sane]

Looking at the BBC news this morning I'm struggling to understand why reintroducing the requirement to use facemasks is such a hot potato: after all, it isn't exact an onerous demand.

Here in Scotland the need to wear them in shops and public transport, and for older kids in secondary school, was never removed - and, anecdotally, compliance with this seems almost universal in my experience.

Definitely not universal on public transport in my experience.

[ProfessorDavey]

Looking at the BBC news this morning I'm struggling to understand why reintroducing the requirement to use facemasks is such a hot potato: after all, it isn't exact an onerous demand.

Here in Scotland the need to wear them in shops and public transport, and for older kids in secondary school, was never removed - and, anecdotally, compliance with this seems almost universal in my experience.

Mask wearing has really dwindled in England since it ceased to be broadly mandatory. And that includes in places where it remains required, for example on London Transport - the problem is that there is no real way to enforce the requirement as the rules only allow LT staff to prevent people from travelling rather than issue fines etc.

[Aruntraveller]

Looking at the BBC news this morning I'm struggling to understand why reintroducing the requirement to use facemasks is such a hot potato: after all, it isn't exact an onerous demand.

Here in Scotland the need to wear them in shops and public transport, and for older kids in secondary school, was never removed - and, anecdotally, compliance with this seems almost universal in my experience.

Kwasi Kwarteng. What a useless politician.

I've just written to my MP (again) about reintroducing the mask mandate. Trying to keep up the pressure, but the government are so obdurate that I fear that wearing my fingers to the bone on a keyboard will have no effect.

[ProfessorDavey]

Kwasi Kwarteng. What a useless politician.

I've just written to my MP (again) about reintroducing the mask mandate. Trying to keep up the pressure, but the government are so obdurate that I fear that wearing my fingers to the bone on a keyboard will have no effect.

My fear is that even if the government reintroduces the mandate it will be impossible to enforce - once you have removed something (mask wearing) I think it will be really hard to reintroduce it. I suspect large swathes of the public will just shrug and carry on maskless.

[Aruntraveller]

My fear is that even if the government reintroduces the mandate it will be impossible to enforce - once you have removed something (mask wearing) I think it will be really hard to reintroduce it. I suspect large swathes of the public will just shrug and carry on maskless.

Possibly, but it could still persuade enough people to change, and that overall change would make a difference.

They have painted themselves into a corner entirely of their own making.