Read on Twitter
~3.2 million 
people may now have #COVID19
~4.7% or 1 in 21. ~10% in London
Assume: 2,822 dead (hosp +20%); IFR 1%; Adj. days to death ~18
So ~282k were infected 18 days ago
~5 days to double so ~3.6 doublings since
So infections to date: ~3.4m, ~6% recovered so ~3.2m now https://twitter.com/DHSCgovuk/status/1245337119721230340
people may now have #COVID19 ~4.7% or 1 in 21. ~10% in London
Assume: 2,822 dead (hosp +20%); IFR 1%; Adj. days to death ~18
So ~282k were infected 18 days ago
~5 days to double so ~3.6 doublings since
So infections to date: ~3.4m, ~6% recovered so ~3.2m now https://twitter.com/DHSCgovuk/status/1245337119721230340
Whole model is v.sensitive to inputs, so low confidence + wide ranges apply.
More deaths --> more infections
Higher IFR% --> fewer infs (don't need as many for same deaths)
Longer days to death --> more infs (more time to double)
Higher doubling rate --> more infs
More deaths --> more infections
Higher IFR% --> fewer infs (don't need as many for same deaths)
Longer days to death --> more infs (more time to double)
Higher doubling rate --> more infs
Main changes:
- Added 20% on top of hospital deaths to estimate total deaths (ONS)
- Increased IFR from 0.9% to 1% to align with new Imperial work + potential ICU stress
- Increased days to double to 5 assuming lockdown helping to slow (UK deaths 3, UK cases 4.5, Italy now 8-11)
- Added 20% on top of hospital deaths to estimate total deaths (ONS)
- Increased IFR from 0.9% to 1% to align with new Imperial work + potential ICU stress
- Increased days to double to 5 assuming lockdown helping to slow (UK deaths 3, UK cases 4.5, Italy now 8-11)
This is a simple, top-down model.
For a pro version that also uses a "death, days to death, transmission speed" approach, read this from Imperial.
Already low given new deaths + non-hospital additions.
https://www.imperial.ac.uk/media/imperial-college/medicine/sph/ide/gida-fellowships/Imperial-College-COVID19-Europe-estimates-and-NPI-impact-30-03-2020.pdf
https://twitter.com/JamieWoodhouse/status/1244917380523995137?s=20
h/t @StefanFSchubert
For a pro version that also uses a "death, days to death, transmission speed" approach, read this from Imperial.
Already low given new deaths + non-hospital additions.
https://www.imperial.ac.uk/media/imperial-college/medicine/sph/ide/gida-fellowships/Imperial-College-COVID19-Europe-estimates-and-NPI-impact-30-03-2020.pdf
https://twitter.com/JamieWoodhouse/status/1244917380523995137?s=20
h/t @StefanFSchubert
It's heartening to finally see some press references to % infected, not just the "confirmed cases" iceberg tip.
https://unherd.com/2020/04/how-likely-are-you-to-die-of-coronavirus/
https://news.sky.com/story/coronavirus-the-data-suggests-the-uk-is-on-course-for-many-thousands-of-deaths-11966517
https://telegraph.co.uk/news/2020/03/29/least-16m-people-could-infected-coronavirus-uk-new-estimates/
https://metro.co.uk/2020/03/30/coronavirus-slowing-uk-thanks-social-distancing-measures-12476442/
https://msn.com/en-gb/news/newslondon/up-to-one-in-10-londoners-may-be-infected-with-coronavirus-expert-warns/ar-BB11HBdk
Way too late...
https://unherd.com/2020/04/how-likely-are-you-to-die-of-coronavirus/
https://news.sky.com/story/coronavirus-the-data-suggests-the-uk-is-on-course-for-many-thousands-of-deaths-11966517
https://telegraph.co.uk/news/2020/03/29/least-16m-people-could-infected-coronavirus-uk-new-estimates/
https://metro.co.uk/2020/03/30/coronavirus-slowing-uk-thanks-social-distancing-measures-12476442/
https://msn.com/en-gb/news/newslondon/up-to-one-in-10-londoners-may-be-infected-with-coronavirus-expert-warns/ar-BB11HBdk
Way too late...
If we were doing population sample testing (as promised here) https://gov.uk/government/news/testing-for-coronavirus-covid-19-will-increase-to-25-000-a-day
we could observe the infection doubling rate.
We could do this tomorrow using a single day's testing capacity.
As nothing has been done/published, we're left extrapolating from deaths.
we could observe the infection doubling rate.
We could do this tomorrow using a single day's testing capacity.
As nothing has been done/published, we're left extrapolating from deaths.
This would imply total UK death toll of ~35k...
But only if IFR remains 1% + we see zero new infections.
Sadly, neither of the above are sound assumptions.
If our ICU capacity is overrun, the IFR% will spike hard.
New infections depends on hard #Lockdown + test/trace.
But only if IFR remains 1% + we see zero new infections.
Sadly, neither of the above are sound assumptions.
If our ICU capacity is overrun, the IFR% will spike hard.
New infections depends on hard #Lockdown + test/trace.
A wave is crashing over our ICUs.
We can't reduce the size of that wave because it's caused by infections from 2-5 weeks ago.
We can improve our readiness by scaling ICUs + protecting NHS staff.
We can stop the wave getting bigger + longer by hard #Lockdown + test/trace.
We can't reduce the size of that wave because it's caused by infections from 2-5 weeks ago.
We can improve our readiness by scaling ICUs + protecting NHS staff.
We can stop the wave getting bigger + longer by hard #Lockdown + test/trace.
A more optimistic view? If #Lockdown has already helped slow infection doubling over last 3 weeks to every 6 days, takes # infections down to ~2.1m.
Still projects 24k death toll assuming ICUs not over-run and zero new infections from today.
Neither are sensible assumptions.
Still projects 24k death toll assuming ICUs not over-run and zero new infections from today.
Neither are sensible assumptions.
It's tempting to think... "There's 2822 deaths and #Covid19 kills about 1 in 100, so there must be ~282k infections".
The problem is you're nearly right. But those ~282k infections were 2-3 weeks ago. That's how long it takes to kill.
They've been doubling every 4-5 days since.
The problem is you're nearly right. But those ~282k infections were 2-3 weeks ago. That's how long it takes to kill.
They've been doubling every 4-5 days since.
This isn't the best way of estimating % infected!
We're waiting for people to die, assuming fatality rate to judge how many infections drove those deaths, then using doubling rates to judge infections today.
A better way? Population sample testing! https://twitter.com/JamieWoodhouse/status/1243875344916111360?s=20
We're waiting for people to die, assuming fatality rate to judge how many infections drove those deaths, then using doubling rates to judge infections today.
A better way? Population sample testing! https://twitter.com/JamieWoodhouse/status/1243875344916111360?s=20
Why is estimating # infected more important than just tested "cases"?
Infected people are doing the infecting. The "cases" are mostly in hospital or dead.
If you know # infected and # deaths you can assess how deadly this thing really is (IFR%, not just "case" fatality)
Infected people are doing the infecting. The "cases" are mostly in hospital or dead. If you know # infected and # deaths you can assess how deadly this thing really is (IFR%, not just "case" fatality)
Telling public % infected helps us comply with hard #Lockdown. BJ's speech should have started:
"There are infected people in every train, in every shop, in every park, in every tube... you might even be one of them... please take what I am about to say very seriously..."
This poll shows a dangerous level of complacency across the UK. I suspect this is worse in the real world.
Most people think less than a million are infected! That's what happens when govt + press only talk about the "confirmed cases" iceberg tip. https://twitter.com/JamieWoodhouse/status/1245291470107672576?s=20
Most people think less than a million are infected! That's what happens when govt + press only talk about the "confirmed cases" iceberg tip. https://twitter.com/JamieWoodhouse/status/1245291470107672576?s=20
"Total infected" tells us how many people are going to be coming through our ICU capacity in the next few weeks and whether that will be overrun.If it is, #Covid19 will kill much more than 1%. When you run out of ICU beds / ventilators, many more die as in Italy/Spain.
If we'd started projecting total infected from day one (ideally via. regular pop. sample tests), we might have acted sooner.
We might also have persuaded people to comply better with our weak #Lockdown.
Instead... "a national scandal" @richardhorton1 https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30727-3/fulltext
We might also have persuaded people to comply better with our weak #Lockdown.
Instead... "a national scandal" @richardhorton1 https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30727-3/fulltext
A powerful visualisation of deadly UK #Covid19 complacency:
"Right things... at the right time..."?
H/t @Imperial_JIDEA (I'll stop my amateur efforts as your weekly reports start to come out - critically important)
"Right things... at the right time..."?
H/t @Imperial_JIDEA (I'll stop my amateur efforts as your weekly reports start to come out - critically important)
