"The Peak"

[dazzer6666]

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.​

Until there's a vaccine there will be further waves - key will be managing the volume of those waves (in my (unqualified) view). We've managed 'Wave 1' (and associated NHS capacity) through extensive lockdown and social distancing - as herd immunity increases the measures necessary to manage the subsequent waves should be increasingly less severe. I can easily envisage a 'rolling' set of measures that get flexed up and down depending on numbers and NHS capacity - and this becoming the norm for us to live with. Taking the football example, could mean something like a game being quite suddenly announced as 'behind closed doors', and could also be geography-specific if numbers spike in a particular area.

 

[Silverhatch]

I think we have been building all these new hospitals and morgues ready for the real peak which will happen once we release lock down.

This is why it’s been done.

 

[dazzer6666]

This is why it’s been done.

Why do you think that ?

 

[Barham's tash]

I've posted about this before and I can't be bothered to go and find it again, but there still seems to be confidence that this is a result of either:

- Incorrect test results
- The virus laying dormant in someone and reactivating later, something I believe is relatively common

In the case of the second possibility, the belief is that people are not infectious at that point.

Fingers crossed though!

As you say fingers crossed that it’s either of those reasons.

It is however somewhat inevitable that covid-19 will either mutate again or more likely we’ll face another avian flu strain of similar if not worse virility.

The Netflix series Pandemic looks at the reasons why in great detail and how we’re finding research into a universal flu vaccine and the progress being made.

It’s quite a fascinating subject were it not for the present situation.

 

[Bozza]

This is why it’s been done.

I really don't think that.

I think the Nightingale hospitals were assembled out of genuine fear that existing NHS services could be critically overwhelmed.

Now, there may be future plans for them, ie they become coronavirus-only facilities, for as long as required, in order to permit existing hospitals in their vicinity to return to BAU, but I really don't think there is an intention to "turn on the virus-spread tap" to such an extent that they become deluged.

 

[Marty___Mcfly]

This model definitely predicts a single peak

https://covid19.healthdata.org/united-kingdom

They base this on the following assumptions:

When can social distancing measures be relaxed?

Our model assumes social distancing stays in place until the pandemic, in its current phase, reaches the point when deaths are less than 0.3 per million people. Based on our latest projections, we expect social distancing measures to be in place through the end of May.

The timeline could change based on what data show about the trajectory of the pandemic. In the meantime, we are working to forecast what would happen if social distancing measures were lifted before the pandemic is under control, and we will share these projections as soon as our work is complete.

Our forecasts of zero deaths in July and August assume that appropriate measures are put in place to guard against the reintroduction of COVID-19 from another state or country. These measures may include mass screening, contact tracing, testing of all individuals entering the country, and quarantine of people who test positive. Details on what these strategies need to be will be analyzed in future editions of the forecasts.

 

[Silverhatch]

Why do you think that ?

I'm not sure that the Nightingales were built for the short term. NHS bed capacity in the UK has gone down by 70000 since 2000. The UK has fewer acute beds relative to its population than many comparable health systems. The Government keeps hammering home that this is a fluid and developing situation. Nightingale Hospitals were/are built to increase our very lacking critical care capacity. But the NHS also cleared the decks to increase capacity in existing hospitals. What appears to have happened (an unintended consequence - Witty was clear about this last night) is that the public are staying away from hospitals even with (other) life-threatening issues (Sepsis for instance).

Another wave of the epidemic/pandemic, once our version of strict lock down is relaxed and until testing/tracing/vaccine is developed, will have the Government broadcasting a slightly different message and indeed probably having a new CV19 NHS 111 and a normal NHS 111.

What are the chances of the Nightingale hospitals being torn down once we a past this peak? I'd hazard a guess at nil.

 

[Spider]

A question for those who kno more about epidemiology than I...

Ignoring the concept of herd immunity, am I wrong in thinking that bringing down the average number of transmissions to less than 1 would, over time, see the virus naturally die out?

With this in mind, could we not think of ways to reduce social contact by >61% (as in 2.5 to <1) whilst having as normal a society as possible. Obviously this would still need big changes but if we try and model the way supermarkets and their customers have adapted in other walks of life (eg pubs have a queue at the bar, limited number of people inside etc.) then we should eventually see cases die out.

I might be totally wrong here as I haven’t heard any discussion of this at all.

 

[dazzer6666]

I'm not sure that the Nightingales were built for the short term. NHS bed capacity in the UK has gone down by 70000 since 2000. The UK has fewer acute beds relative to its population than many comparable health systems. The Government keeps hammering home that this is a fluid and developing situation. Nightingale Hospitals were/are built to increase our very lacking critical care capacity. But the NHS also cleared the decks to increase capacity in existing hospitals. What appears to have happened (an unintended consequence - Witty was clear about this last night) is that the public are staying away from hospitals even with (other) life-threatening issues (Sepsis for instance).

Another wave of the epidemic/pandemic, once our version of strict lock down is relaxed and until testing/tracing/vaccine is developed, will have the Government broadcasting a slightly different message and indeed probably having a new CV19 NHS 111 and a normal NHS 111.

What are the chances of the Nightingale hospitals being torn down once we a past this peak? I'd hazard a guess at nil.

I think they were - there was real panic about the potential numbers based on the modelling (and what was going on in Italy and Spain in particular) and recognition that the NHS was already at near-capacity and was about to be overwhelmed. A combination of social distancing, discharging anyone and everyone who was remotely able to be sent home, cancelling planned admission for ops etc and only admitting severe COVID19 cases has meant the 'worst case' numbers have been nowhere near reached. We won't need the Nightingales much going forward as lockdown won't be fully eased for a very long time - it'll be in stages, and occasionally ramped back up when necessary to manage the ongoing flow of patient numbers until there is clear herd immunity and/or a vaccine.

 

[Bozza]

A question for those who kno more about epidemiology than I...

Ignoring the concept of herd immunity, am I wrong in thinking that bringing down the average number of transmissions to less than 1 would, over time, see the virus naturally die out?

With this in mind, could we not think of ways to reduce social contact by >61% (as in 2.5 to <1) whilst having as normal a society as possible. Obviously this would still need big changes but if we try and model the way supermarkets and their customers have adapted in other walks of life (eg pubs have a queue at the bar, limited number of people inside etc.) then we should eventually see cases die out.

I might be totally wrong here as I haven’t heard any discussion of this at all.

Pretty much, yes. And that may be how we proceed, with the expectation that we may have to ramp up restrictions, at times, if NHS load is looking like it's going to exceed capacity.

Scientists used an online survey to ask 1,300 people in Britain to list their contacts for the previous day - and found that the average number of contacts now is more than 70% lower than before the lockdown.

“If we see similar changes across the UK population, we would expect to see the epidemic to start to decline,” said John Edmunds, who led the study at the London School of Hygiene & Tropical Medicine (LSHTM).

The finding that the mean number of contacts per person measured is more than 70% lower now than before the lockdown suggests that the R0 reproduction value now would be between 0.37 and 0.89, they said, with the most likely value being 0.62.

https://www.reuters.com/article/us-...n-is-slowing-spread-of-covid-19-idUSKBN21J56W​

 

[Herr Tubthumper]

A question for those who kno more about epidemiology than I...

Ignoring the concept of herd immunity, am I wrong in thinking that bringing down the average number of transmissions to less than 1 would, over time, see the virus naturally die out?

With this in mind, could we not think of ways to reduce social contact by >61% (as in 2.5 to <1) whilst having as normal a society as possible. Obviously this would still need big changes but if we try and model the way supermarkets and their customers have adapted in other walks of life (eg pubs have a queue at the bar, limited number of people inside etc.) then we should eventually see cases die out.

I might be totally wrong here as I haven’t heard any discussion of this at all.

It’s been announced in Germany our infection rate is now on average <1 person. It won’t make it die, but it’s certainly manageable. This will inform future decisions as we start our move out of the current lock down on Monday; watch this space for your answers.

https://www.bbc.com/news/live/world-52319956

 

[CheeseRolls]

A question for those who kno more about epidemiology than I...

Ignoring the concept of herd immunity, am I wrong in thinking that bringing down the average number of transmissions to less than 1 would, over time, see the virus naturally die out?

With this in mind, could we not think of ways to reduce social contact by >61% (as in 2.5 to <1) whilst having as normal a society as possible. Obviously this would still need big changes but if we try and model the way supermarkets and their customers have adapted in other walks of life (eg pubs have a queue at the bar, limited number of people inside etc.) then we should eventually see cases die out.

I might be totally wrong here as I haven’t heard any discussion of this at all.

I don't think that it will naturally die out in these circumstances. My understanding is it would bring it to a level where it could be managed and contained, by testing, tracing and localised quarantine to contain outbreaks.

 

[Bodian]

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.

Also, as time goes on, those who were most likely to die from/with it, will have done so - thereby reducing the number who are most vulnerable and thereby generally enhancing the ability of the population as a whole to reduce transmission / effects of it.

 

[Mellotron]

2m, if correct, is tiny. That would mean 64m (or 97%) of the population would still be susceptible, which ties in perfectly with this, also from today:

Costello had earlier suggested the UK may face eight to 10 waves of the virus before herd immunity is possible, citing a study of Dutch blood donors suggesting only three per cent of the country has developed meaningful immunity.​

Not quite right.

They aren’t suggesting a peak of 2million overall, but on one particular day. Also, they referred only to symptomatic COVID, and don’t include the anywhere between 20-80% asymptomatic. Therefore, they are possibly suggesting as many as 6-8million overall by the end of this first wave, perhaps less, perhaps more.

Also, say we’ve managed to get the R level to around 0.6, it’s quite possible we could relax certain things over coming months whilst still keeping below 1 - which would mean the virus continuing to peter out overall.

I recommend you have a look at the Royal College’s website, you can get to it via your app. It’s full of fascinating data that is no doubt partially guiding their decisions.