Coronavirus

[Witton Park]

It can be both! R does not tell you how many have got it/have had it - it simply tells you how many are infected by the average person with infection.

Most have not had it because most have not yet been exposed to it; when exposed, most get it. Of those, all are asymptomatic to start with, yet can spread it; some never develop significant symptoms, a % never develop any symptoms. Of course some unlucky ones end up in hospital, some very unlucky ones die.

Mike this is rubbish.

R = 4
It doesn't tell you how many have got it, but it tells you how many will get it.

If R was 4 pre lockdown, then 10-20 million would have had it before lockdown.

Or R wasn't 4.

[Fellbeast]

The last best guesstimate I saw of the overall U.K. infection rate was 5% of the population, with London and the south east viewed in isolation at around 20%. Herd immunity is effective at 82%

[Travs]

Interesting phone call this morning...

Firstly, furlough ending and back to office from next wednesday! Although potential to revert to part-time/part-furlough in the future if necessary.

Secondly, director was rushed into hospital a week ago with suspected heart-attack. After extensive testing he has a perfectly healthy heat/lungs for his age. However he did suffer quite badly with Corona a coupe of months back, and the pains are suspected as related to this. Apparently the hospitals are seeing a few similar occureneces of chest issues in people who have had corona...

[molehill]

This is what worries me most about catching the virus, I think I would be very unlucky to die from it (being quite fit and healthy for my age) but I do fear long term or irreparable damage to organs somehow. My twilight years would be little fun with a heart or lungs that only functioned 50% (for instance).
I do fear that the "death numbers" may only be the tip of the iceberg when it comes to damage done.

[Mike T]

Mike this is rubbish.

R = 4
It doesn't tell you how many have got it, but it tells you how many will get it.

If R was 4 pre lockdown, then 10-20 million would have had it before lockdown.

Or R wasn't 4.

Some different estimates of R:

https://www.mrc-bsu.cam.ac.uk/now-casting/

[Wheeze]

What we are seeing is unexpected rates of poor resolution of lung changes on imaging. In diseases like influenza any chest x ray changes during the active phase generally resolve. But covid often seems to leave behind changes that are much slower to resolve. This raises the spectre of pulmonary fibrosis, a permanent of sometimes progressive deterioration in lung function...like miners or dust workers lung disease.

[Witton Park]

Some different estimates of R:

https://www.mrc-bsu.cam.ac.uk/now-casting/

I'm sorry Mike, and I appreciate your background, but we have been presented with an assessment that R=4 up to lockdown.
If that R4 "tells you how many are infected by the average person with infection" then it tells you that we will have a huge and rapid rise in the infection - in fact it would be so huge that it would start hitting herd immunity before 10 weeks.

[Mike T]

As to how many infections there are/will be in a population with an infection with an R of X depends on 1/ how many cases you start with 2/ the cycle time and 3/ how many cycles you have before taking measures to change R. There are formulas for this - epidemiologists will know this - are they wrong? I know some have come up with somewhat different results for R, but of course R is not fixed (unless you define it as such), and varies with both both time and place.

The biggest unknown - and an obvious influencer - is the cycle time - how long from being infected before someone then starts to infect others. If this is just a day, numbers will rise very quickly, if it is 2 weeks, it will clearly take much longer. Again, epidemiologists will know this, and have ways of estimating cycle time from the data available.

Do you feel R was a lot lower, and lockdown has had little influence, or that R was high, and far more have been infected than than the generally accepted 5% (10% in London)?

[Witton Park]

I feel the R of 4 might be about right.
I understand the cycle time is thought to be around 5 days - that seems the settled thought.
As I've set out previously an R of 4 (as set out in the piece I think you referred to earlier), a cycle time of 5 days, would mean from just 1 person, we would have had circa 1/3 of the population infected prior to lockdown.

I don't "know" as such. All I see is assertions that don't stack up.

An R of 4 (backed up by the speed and depth a processing plant can be gone through) just doesn't sit alongside a 5% level of infection in the population.

So something is wrong.

[Mike T]

What we are seeing is unexpected rates of poor resolution of lung changes on imaging. In diseases like influenza any chest x ray changes during the active phase generally resolve. But covid often seems to leave behind changes that are much slower to resolve. This raises the spectre of pulmonary fibrosis, a permanent of sometimes progressive deterioration in lung function...like miners or dust workers lung disease.

I know that some cases of Covid with no actual symptoms have had changes in their lungs on CT. Even with "ordinary" pneumonia it can take ages for even CXR appearances to return to normal, much less CT appearances.

I would be surprised if people end up with progressive fibrosis, but clearly some people's acute lung damage is fatal, and others, some quite young, have needed lung transplants.

There is clearly a lot we do not yet know about the longterm effects of Covid.