Herd immunity and risk characteristics of 'healthy' people

[JonathanH]

I think the admission of Boris Johnson to intensive care illustrates clearly why 'herd immunity' is not a strategy which can be followed until the risk characteristics of 'healthy' people are fully understood. Unfortunately, we need time to understand this problem.

Although I appreciate that it has to go through the population, the longer individual people can put off getting this disease the better.

I wish the press would stop pressing on the 'peak' as if the number of victims is going to go down in the near future - it is going to plateau at best, and plateau for a long long time.

 

[Bletchleyite]

The "peak" is the danger for the NHS, though. If it goes above the ICU capacity, that means people start dying not because their body can't cope with the disease with treatment, which is what's happening now, but because they cannot receive any treatment.

Flatlining, provided it's below the capacity of the NHS, is not a situation to fear in the same way.

 

[87 027]

Some interesting reports in the press today that it has not been definitively established whether those who have had extremely mild symptoms are immune in the future. I had aches and fever for a week but everyone else in my house got away with a couple of days of very minor symptoms. Have I had Covid-19? Don't know, in the absence of testing. Am I and the rest of my family now immune? Can't say - so many gaps in knowledge at this stage of events.

 

[JonathanH]

The "peak" is the danger for the NHS, though. If it goes above the ICU capacity, that means people start dying not because their body can't cope with the disease with treatment, which is what's happening now, but because they cannot receive any treatment.

Flatlining, provided it's below the capacity of the NHS, is not a situation to fear in the same way.

Yes, but I think they would be better asking when the "flatline" point is coming. A "peak" implies that the numbers are going to somehow come down.

 

[Bedpan]

Well they will start coming down after the peak. but that presents its own problem as it might make people become a bit more relaxed when they shouldn't. I for one will breath a sigh of relief when the peak passes, buut in reality all that wwill mean is that "only" say 700 people a day will be dying instead of say 800, so the world will still be a dangerous place to live in.

 

[JonathanH]

Well they will start coming down after the peak. but that presents its own problem as it might make people become a bit more relaxed when they shouldn't. I for one will breath a sigh of relief when the peak passes, buut in reality all that wwill mean is that "only" say 700 people a day will be dying instead of say 800, so the world will still be a dangerous place to live in.

Yes, but any relaxation of restrictions just means you reach the peak again.

 

[yorkie]

Well they will start coming down after the peak. but that presents its own problem as it might make people become a bit more relaxed when they shouldn't. I for one will breath a sigh of relief when the peak passes, buut in reality all that wwill mean is that "only" say 700 people a day will be dying instead of say 800, so the world will still be a dangerous place to live in.

Not really; if the aim is achieved - which is to avoid overwhelming the health service - then it's not true to say the world will be a dangerous place, because if you are one of the small minority who is unlucky and ends up being hospitalised you would still be highly likely to survive.

 

[Bedpan]

Not really; if the aim is achieved - which is to avoid overwhelming the health service - then it's not true to say the world will be a dangerous place, because if you are one of the small minority who is unlucky and ends up being hospitalised you would still be highly likely to survive.

Well yes, that's true. It will be less dangerous than it would be if the NHS is overwhelmed, but having had an ex colleague die from it and one of my daughter's friends in hospital for six days, I am still worried about me and my family getting it.

 

[leightonbd]

The Achilles heel for any strategy involving a calculation that the peak has been reached, as the key to loosening restrictions, is the lack of antibody testing.

Without this, it’s a complete shot in the dark as to the extent of any herd immunity, with no guarantee you won’t trigger a rush of further cases, a second peak, going over hospital capacity, etc.

 

[hwl]

The Achilles heel for any strategy involving a calculation that the peak has been reached, as the key to loosening restrictions, is the lack of antibody testing.

Without this, it’s a complete shot in the dark as to the extent of any herd immunity, with no guarantee you won’t trigger a rush of further cases, a second peak, going over hospital capacity, etc.

There are going to be second, third, forth etc. peaks as restrictions are relaxed, the question is just how big they are. Hence each easing of restrictions needs to be carefully calibrated both in scope and with reference to background levels of immunity developed in the wider community.

 

[Bletchleyite]

There are going to be second, third, forth etc. peaks as restrictions are relaxed, the question is just how big they are. Hence each easing of restrictions needs to be carefully calibrated both in scope and with reference to background levels of immunity developed in the wider community.

If they are doing what this guy suggests, and it seems they are, there will be lots of mini-peaks:

https://medium.com/@tomaspueyo/coronavirus-the-hammer-and-the-dance-be9337092b56

 

[Mogster]

Some interesting reports in the press today that it has not been definitively established whether those who have had extremely mild symptoms are immune in the future. I had aches and fever for a week but everyone else in my house got away with a couple of days of very minor symptoms. Have I had Covid-19? Don't know, in the absence of testing. Am I and the rest of my family now immune? Can't say - so many gaps in knowledge at this stage of events.

Immunity is a complex biological process, no two people respond in the same way. At work we are vaccinated against hepatitis B and have our antibody level monitored, some people produce stonking results, others next to nothing.

One positive thing is that people do produce effective and long lasting antibodies to the very closely related SARS virus. People who were infected with SARS 15+ years ago are still producing detectable and effective antibodies today. Hopefully our response to CoV2 will be similar.

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30788-1/fulltext

Hibberd argues that once people produce antibodies against a particular coronavirus, they probably have immunity for life. Indeed, Wang's laboratory has investigated how long immunity against SARS-CoV and Middle East respiratory syndrome coronavirus lasts. “17 years later, a SARS survivor still has neutralising antibodies against SARS—we found that not only were the antibodies there, but they could still neutralise the SARS virus.”

 

[Tetchytyke]

There are going to be second, third, forth etc. peaks as restrictions are relaxed, the question is just how big they are.

We know it takes about two weeks for the effects of any changes to be felt, and we now have more data about what changes will have the biggest effect. I expect restrictions to be loosened very slowly and gradually, at three week intervals, so they can easily be reinstated if numbers don't match the estimates.

The restrictions aren't to stop people getting it, they're to stop everyone getting it all at the same time.

 

[Bletchleyite]

The restrictions aren't to stop people getting it, they're to stop everyone getting it all at the same time.

Correct. A lot of people don't understand that, and they are the ones calling for panic, "full" lockdown (i.e. not even allowed to buy food) etc.

 

[Gooner18]

I personally think they went for the herd theory due to data China had released , however, as it started to rip through the world it became clear China have lied and fudged the true figures , thusly causing the turn around

 

[bramling]

Correct. A lot of people don't understand that, and they are the ones calling for panic, "full" lockdown (i.e. not even allowed to buy food) etc.

I’m afraid this isn’t quite the full picture. There’s also the issue that key workers are working on the basis of 2m separation, which of course includes when travelling to or from work. There’s already quite a bit anger building up seeing others (in many cases being paid to) sunbathe, not to mention issues like doing 12 hours at work and then having to queue for a supermarket because people aren’t going shopping “as infrequently as possible”. Release elements of the lockdown and I guarantee there will be a heavy reduction in key worker availability, just at the time the country can bear it least. Certainly the transport industry has made representations to the government over this, and I bet they’re not the only ones.

Needless to say, no key workers could quite quickly mean no transport, no food, no NHS, etc. I’m not claiming there’s an easy solution, but don’t underestimate the anger building up behind the scenes. Compared to people whinging about boredom at home, this is a much more serious issue.

The weekend before the lockdown was hurrendous for key workers, and I can guarantee had the lockdown not come in there would have been some serious discontent in this sector. This isn’t going to change, especially as we’re now seeing serious things like the PM in intensive care and colleagues passing away. Please remember elements of many key industries, railway control being one, are at times only a couple of people away from being unable to run. A lot is running on goodwill and dedication at the minute, this is already strained and could erode away very readily.

 

[Bletchleyite]

There’s already quite a bit anger building up seeing others (in many cases being paid to) sunbathe not to mention issues like doing 12 hours at work and then having to queue for a supermarket.

I have time for this, and then I don't have time for this. Some of it is a bit unfair, but life is unfair. Anger is the wrong emotion.

I do wonder if some people might use this as an opportunity to evaluate if they're in the right career. In a way it is making me wish I was a key worker, though now I've got my hand sanitiser delivered I'm probably going to start NHS volunteering over the long weekend (can't really usefully do it on weekdays because of shortened shop and pharmacy opening hours).

Also a lot of people (key workers and not) are just making wrong choices over shopping. The supermarkets are a zoo, but I'm finding the local shops very much aren't.

 

[hwl]

I’m afraid this isn’t quite the full picture. There’s also the issue that key workers are working on the basis of 2m separation, which of course includes when travelling to or from work. There’s already quite a bit anger building up seeing others (in many cases being paid to) sunbathe not to mention issues like doing 12 hours at work and then having to queue for a supermarket. Release elements of the lockdown and I guarantee there will be a heavy reduction in key worker availability, just at the time the country can bear it least. Certainly the transport industry has made representations to the government over this, and I bet they’re not the only ones.

Needless to say, no key workers could quite quickly mean no transport, no food, no NHS, etc. I’m not claiming there’s an easy solution, but don’t underestimate the anger building up behind the scenes. Compared to people whinging about boredom at home, this is a much more serious issue.

The weekend before the lockdown was horrendous for key workers, and I can guarantee had the lockdown not come in there would have been some serious discontent in this sector. This isn’t going to change, especially as we’re now seeing serious things like the PM in intensive care and colleagues passing away. Please remember elements of many key industries, railway control being one, are at times only a couple of people away from being unable to run.

Hence as very small first steps as the potential impact from certain already stretched sectors being hit harder could be problematic.
It isn't just the numbers but what they do and where... Average can be a bit dangerous here.
Several key worker sectors reporting 10-15% reductions in staff at the moment, some more especially localised clusters.

It could take till June to get a sensible levels of immunity to provide resilience of service in some organisations / sectors.

 

[bramling]

I have time for this, and then I don't have time for this. Some of it is a bit unfair, but life is unfair. Anger is the wrong emotion.

I do wonder if some people might use this as an opportunity to evaluate if they're in the right career. In a way it is making me wish I was a key worker, though now I've got my hand sanitiser delivered I'm probably going to start NHS volunteering over the long weekend (can't really usefully do it on weekdays because of shortened shop and pharmacy opening hours).

Also a lot of people (key workers and not) are just making wrong choices over shopping. The supermarkets are a zoo, but I'm finding the local shops very much aren't.

Whether you have time for it or not in the grand scheme of things counts for zero. At this moment the country is pretty reliant on these people, and it is not going to wash sending them out to work if others cannot respect the government guidance - principally the various social distancing measures.

People are, quite reasonably in my view, not going to work to be coughed over by people failing to respect social distancing. Quite simply this is what was happening the weekend before the lockdown. As I said before, the government is very aware of this.

It leaves a *very* sour taste in the mouth to see and hear people moaning that they can’t go sunbathing or honeypotting, whilst others are - quite literally - keeping food on tables, keeping the lights on, keeping the ventilators running, ensuring the hospitals are staffed, et cetera. Especially when there’s, clearly, some element of risk involved in doing it. The least everyone can do is respect that and endeavour to do everything possible to minimise that risk.

The PM going into intensive care may well prove to be the straw breaking the camel’s back for many, especially those at or above the 50-55 range. Certainly I’m picking up a vibe that ears have pricked up very sharply to this.

As for re-evaluating lines of work, I don’t think *anyone* is in the business of going to work and catching a not-fully-understood and potentially fatal disease, simply to facilitate a load of bored families fancying a day out at the beach.

The government has implemented a pretty generous package to help people economically. Indeed some would say it's over generous bearing in mind the huge burden it's going to place on the taxpayer going forward. Even Sunak seems to be now getting the jitters about the extent to which public funds are sloshing around. The very least people can do in return is simply respect the government's guidelines. All this looking for loopholes and arguing about how vital it is to get loads of exercise per day I'm afraid I find utterly pathetic.

 

[bramling]

Hence as very small first steps as the potential impact from certain already stretched sectors being hit harder could be problematic.
It isn't just the numbers but what they do and where... Average can be a bit dangerous here.
Several key worker sectors reporting 10-15% reductions in staff at the moment, some more especially localised clusters.

It could take till June to get a sensible levels of immunity to provide resilience of service in some organisations / sectors.

As I said initially, there's simply no easy answer and solution to this. Certainly where I am the 10-15% figure would be an under-representation. We have driver absence in some areas of nearer 30%. Some teams have over 50% of people off, and in one case I know over 75%. Naturally overtime is going through the roof, and naturally there's a lot of juggling going on to cover essential positions.

People do *not* have to participate in this juggling, they're doing it out of goodwill and because people genuinely want to do their bit to help the country through this. However anger is building very quickly. It really isn't helping that there's a noticeable increase in people out and about these last couple of days. Where I am there's also been a noticeable increase in passenger-related disturbances on trains and at stations, and it isn't the key workers responsible for this.

 

[DarloRich]

@bramling has this spot on.

Well said

 

[AM9]

@bramling has this spot on.

Well said

Same here, I find myself agreeing with three consecutive posts from bramling. These are strange times.

 

[Mainline421]

The restrictions aren't to stop people getting it, they're to stop everyone getting it all at the same time.

Correct. A lot of people don't understand that, and they are the ones calling for panic, "full" lockdown (i.e. not even allowed to buy food) etc.

Quite it seems almost nobody understands that herd immunity is still and always was the plan, it's just not seen as politically acceptable to spell this out. The only way life can go back to normal is when >50% of the population is immune, this could be through infections or a vaccine, but that's realistically years away, and infections will continue whatever measures are out in place.

 

[edwin_m]

Quite it seems almost nobody understands that herd immunity is still and always was the plan, it's just not seen as politically acceptable to spell this out. The only way life can go back to normal is when >50% of the population is immune, this could be through infections or a vaccine, but that's realistically years away, and infections will continue whatever measures are out in place.

Have you done the math on this? By my simple reckoning it will take several years to get to herd immunity unless the rate of infection is high enough that the number of hospital cases overwhelms the NHS. At that point the death rate shoots up because people who would have survived don't get the treatment that would allow them to.

I personally think they went for the herd theory due to data China had released , however, as it started to rip through the world it became clear China have lied and fudged the true figures , thusly causing the turn around

I did the math mentioned above at about the time the government was moving off herd immunity, using numbers that were fairly easy to find without any inside knowledge. It was blindingly obvious it wouldn't work.

 

[yorkie]

Has ayone read the link @Bletchleyite posted above https://medium.com/@tomaspueyo/coronavirus-the-hammer-and-the-dance-be9337092b56 ?

It's actually very interesting...

During the Hammer period, politicians want to lower R as much as possible, through measures that remain tolerable for the population. In Hubei, they went all the way to 0.32. We might not need that: maybe just to 0.5 or 0.6.

But during the Dance of the R period, they want to hover as close to 1 as possible, while staying below it over the long term term. That prevents a new outbreak, while eliminating the most drastic measures.

 

[Cowley]

Has ayone read the link @Bletchleyite posted above https://medium.com/@tomaspueyo/coronavirus-the-hammer-and-the-dance-be9337092b56 ?

It's actually very interesting...

I just read it and it is very well put.

 

[CaptainHaddock]

I think the admission of Boris Johnson to intensive care illustrates clearly why 'herd immunity' is not a strategy which can be followed until the risk characteristics of 'healthy' people are fully understood. Unfortunately, we need time to understand this problem.

Although I appreciate that it has to go through the population, the longer individual people can put off getting this disease the better.

I wish the press would stop pressing on the 'peak' as if the number of victims is going to go down in the near future - it is going to plateau at best, and plateau for a long long time.

Congratulations on your ability to see into the future!

For all your negativity, we simply don't know what's going to happen next. Most experts agree that we're nearing the peak, indeed we may already have reached it given that the reported daily figures often lag behind the actual stats. From the government's daily briefings, new cases of the virus seem to be stabilising at the 4,000 a day mark.

Once that peak is reached, it's perfectly rational to assume that the number of new cases will fall, as the less people catch the virus, the less people there are to spread it. There is also the theory that the warmer weather will reduce the number of new cases, just as most flu viruses tend to die out in the summer.

Yes, we're by no means out of the woods yet, but I remain confident that the worst of the pandemic will soon be behind us.

 

[Mainline421]

Have you done the math on this? By my simple reckoning it will take several years to get to herd immunity unless the rate of infection is high enough that the number of hospital cases overwhelms the NHS. At that point the death rate shoots up because people who would have survived don't get the treatment that would allow them to.

No, but doing it right now is a little worrying. The growth is exponential so assuming the infection rate is still (averages) each infected person infects 2 others and that everyone they infect is within the first 2 weeks before they self-isolate themselves it would take 50 weeks from the first case to when we start achieving her immunity. (1x2^25=33,555,432). Obviously that's still very flawed in reality for many reasons, but it means it likely won't be until the autumn the lockdown will end. If the infection rate reduced it will take longer but it will still be exponential so will continue "accelerating" every day as there's still gonna be more people spreading the disease.

 

[yorkie]

... If the infection rate reduced it will take longer but it will still be exponential so will continue "accelerating" every day as there's still gonna be more people spreading the disease.

Not so.

https://www.telegraph.co.uk/global-...number-one-important-covid-19-sweeps-britain/

To bring an outbreak under control the R0 value needs to drop below one...

“This would be sufficient to reduce R0 from a value from 2.6 before the lockdown to 0.62 during the lockdown, indicating that physical distancing interventions are effective,” the study, which tracked over 1,300 adults and has not yet been peer reviewed, concluded.

Once it's under control I believe the aim will be to get to just under (but very close to) 1.

 

[hwl]

Has anyone read the link @Bletchleyite posted above https://medium.com/@tomaspueyo/coronavirus-the-hammer-and-the-dance-be9337092b56 ?

It's actually very interesting...

Yes very good piece of analysis.
The reckoning is that we are seeing R down to around 0.6-0.65 in UK.
Keeping R just below 1 will be very hard in the early rounds of easings and will need lots of thought and preparation (e.g. The INEOS hand sanitiser factory needs to have flooded the distribution channels for a long time to improve hygiene in the community.) + all the antibody testing.