"The Peak"

Marty___Mcfly said:

'Herd immunity' I think means the point where enough people have had it for the virus to die out entirely. We don't need that, we just need enough people to have had it, so that there are significantly less available hosts, and the spread slows significantly. I think Governments envisage that as that scenario evolves, they can also slowly relax lockdown measures, and there won't be second spike / wave, and hospitals will remain below capacity.

Testing and targeted isolation would also help to slow the spread.

Basically, just managing the situation as immunity builds in the population.

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Marty___Mcfly said:

'Herd immunity' I think means the point where enough people have had it for the virus to die out entirely. We don't need that, we just need enough people to have had it, so that there are significantly less available hosts, and the spread slows significantly. I think Governments envisage that as that scenario evolves, they can also slowly relax lockdown measures, and there won't be second spike / wave, and hospitals will remain below capacity.

Testing and targeted isolation would also help to slow the spread.

Basically, just managing the situation as immunity builds in the population.

Click to expand...

Marty___Mcfly said:

'Herd immunity' I think means the point where enough people have had it for the virus to die out entirely. We don't need that, we just need enough people to have had it, so that there are significantly less available hosts, and the spread slows significantly. I think Governments envisage that as that scenario evolves, they can also slowly relax lockdown measures, and there won't be second spike / wave, and hospitals will remain below capacity.

Testing and targeted isolation would also help to slow the spread.

Basically, just managing the situation as immunity builds in the population.

Click to expand...

Bozza said:

Without serology/antibody testing being available we don't know how many people have had it, ie all those who had very mild cases or were completely asymptomatic, but I've seen nothing credible that suggests this number is going to be particularly high right now.

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Notters said:

There seems to be a new study nearly every day that suggests this number will be fairly high - as does the King's College data. Am I missing something?

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Bozza said:

I've been getting annoyed at the repeated talk about the peak. Singular. There's only going to be one peak. Get over that peak, start heading down the other side and things can start to change.

Surely the only way there could be just the one peak is largely keeping the current restrictions in place until such time as there is a vaccine available at scale.

Without serology/antibody testing being available we don't know how many people have had it, ie all those who had very mild cases or were completely asymptomatic, but I've seen nothing credible that suggests this number is going to be particularly high right now.

Any loosening of restrictions will surely see the virus begin to spread again, and result in an upturn of infections, hospitalisations and, sadly, deaths. Now, it may be the case that at those times we ratchet up social restrictions again to throttle the spread to ensure we don't overwhelm the NHS. We then peak again, come down from the peak and have another period of relaxation. Rinse and repeat until a vaccine arrives and/or we just reach the point that so many people have had it, we achieve herd immunity.

I keep meaning to write about this, but didn't get round to it, but have done so having just read the below on the BBC live feed of news items...

UK warned of 'further waves' of infections

Health Secretary Matt Hancock is facing questions from the UK's Health and Social Care Committee about the government's response to the coronavirus pandemic.

Earlier, Prof Anthony Costello of University College London's Institute for Global Health warned that the UK was "going to face further waves" of infections.

"If we're going to suppress the chain of transmission of this virus in the next stage we all hope that the national lockdown and social distancing will bring about a large suppression of the epidemic so far - but we're going to face further waves," he told the committee at a virtual session.​

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Bozza said:

What are you deeming "fairly high"?

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Notters said:

Well the King's College app suggests 2 million had it at once on ~8th April. I don't think they've given a figure for the whole period yet (since the end of Jan), but it would be many more million.

Don't get me wrong, I agree with your general point and clearly antibody testing needs to be done to find out if this is the case.

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Bozza said:

I've been getting annoyed at the repeated talk about the peak. Singular. There's only going to be one peak. Get over that peak, start heading down the other side and things can start to change.

Surely the only way there could be just the one peak is largely keeping the current restrictions in place until such time as there is a vaccine available at scale.

Without serology/antibody testing being available we don't know how many people have had it, ie all those who had very mild cases or were completely asymptomatic, but I've seen nothing credible that suggests this number is going to be particularly high right now.

Any loosening of restrictions will surely see the virus begin to spread again, and result in an upturn of infections, hospitalisations and, sadly, deaths. Now, it may be the case that at those times we ratchet up social restrictions again to throttle the spread to ensure we don't overwhelm the NHS. We then peak again, come down from the peak and have another period of relaxation. Rinse and repeat until a vaccine arrives and/or we just reach the point that so many people have had it, we achieve herd immunity.

I keep meaning to write about this, but didn't get round to it, but have done so having just read the below on the BBC live feed of news items...

UK warned of 'further waves' of infections

Health Secretary Matt Hancock is facing questions from the UK's Health and Social Care Committee about the government's response to the coronavirus pandemic.

Earlier, Prof Anthony Costello of University College London's Institute for Global Health warned that the UK was "going to face further waves" of infections.

"If we're going to suppress the chain of transmission of this virus in the next stage we all hope that the national lockdown and social distancing will bring about a large suppression of the epidemic so far - but we're going to face further waves," he told the committee at a virtual session.​

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Bozza said:

I'm not sure my use of R0 (how many people each infected person subsequently infects) is technically correct here, but as more and more of a population have had the virus then the R0 of the virus within that population will start to fall as there are less available hosts available for the virus to spread to.

So, as the infected-and-recovered (or infected and didn't even know they had it) percentage of the population increases, there is a greater probability that a newly-infected person meets fewer people susceptible to catching the virus, and that will be a shift that gradually evolves over time.

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Barham's tash said:

The problem with a novel virus is that herd immunity only works if the virus doesn’t mutate.

There is some evidence of people in Asia having contracted it twice suggesting a new mutation or that one of the known strains can re-infect people which of course would be worrying if they fully released lockdown.

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