Not testing frontline HCPs who are symptomatic might be strategy and not due to capacity problems.
If 1 in 4 negative test results are actually wrong (these clinicians actually have Covid19) and the incorrect result means they then go into work with huge numbers of vulnerable patients, then that is very dangerous indeed.
Might be better for them to sit it out and self-isolate for 7 days to be sure.
Perhaps that's what PHE are doing but are reluctant to reveal for obvious reasons. Namely the reaction.. 'what!? the tests are actually wrong!?!!' from the usual idiot crowd.
Yes - how dare the independent give over their opinion column to an academic/nurse specializing in mental health? Who do they think they are?
It's very good advice to reduce your alcohol consumption at the present time. In addition to the links between immune system & alcohol, cutting down on drinking could also help people lose weight, which is associated with bad outcomes if you do get COVID 19.
People should be able to drink or not drink as they wish, we have enough nanny state as it is. Unfortunately I am down to my last 2 bottles of beer, I may need assistance.
Not testing frontline HCPs who are symptomatic might be strategy and not due to capacity problems.
If 1 in 4 negative test results are actually wrong (these clinicians actually have Covid19) and the incorrect result means they then go into work with huge numbers of vulnerable patients, then that is very dangerous indeed.
Might be better for them to sit it out and self-isolate for 7 days to be sure.
Perhaps that's what PHE are doing but are reluctant to reveal for obvious reasons. Namely the reaction.. 'what!? the tests are actually wrong!?!!' from the usual idiot crowd.
I think that's why there around 7 people per 10 tests at the moment. Negative results may be double checked.
Not testing frontline HCPs who are symptomatic might be strategy and not due to capacity problems.
If 1 in 4 negative test results are actually wrong (these clinicians actually have Covid19) and the incorrect result means they then go into work with huge numbers of vulnerable patients, then that is very dangerous indeed.
Might be better for them to sit it out and self-isolate for 7 days to be sure.
Perhaps that's what PHE are doing but are reluctant to reveal for obvious reasons. Namely the reaction.. 'what!? the tests are actually wrong!?!!' from the usual idiot crowd.
This was why I was trying to find a scientific answer to the 2 questions...
1) What is the accuracy of the current test? 2) What is the accuracy of diagnosis via symptoms?
It might actually be the case that diagnosis is better than the test....
Latest figures log rate per million population. Italy definitely seems to be flattening off. Most countries still on an exponential line regardless of steps taken, but that's no surprise at all when you think about it (the deaths being recorded today were probably from infections around 7th-11th of March. Realistically, only Italy has had enough time since lockdowns for any real effect to be taken. (It would be good for journalists to point out the lag issue at some point)
We're still tracking extremely close to Italy + 15 days. Not sure exactly when our lockdown measures came into place vs theirs, though
It is interesting that Sweden's line is the same as other Countries
Well, yes. Most of the deaths currently will be from infections on 7th-11th of March, when most countries didn't have many steps yet taken.
Just imagine how different the situation would be if there were some random testing going on in these countries, so that we weren't just blundering around in the dark guessing about how many cases there really were, or waiting for changes in the death statistics, which lag several weeks behind.
I wonder - can people not see that kind of information would actually enable countries not so far along the curve to make sensible, evidence-based decisions, and might enable hundreds of thousands, if not millions of lives to be saved?
If the govt went out and did 100k random tests tomorrow and 95% came back negative, wouldn't that be a waste of time/resources?
Given the 40%+ positive figures, it appears that testing is being done only on suspected cases. Which makes more sense to me.
I can't see the point in testing millions of people who've been stuck at home for a fortnight (NHS workers aside) knowing that when they emerge back outdoors they are going to get it anyway.
Surely the only positive thing a govt can do is play for time to help the NHS. They are resigned to the fact 80%+ of us will get the illness and are doing this lockdown to try to stagger it. Testing won't stop people getting it.
If those 100,000 tests were of key workers who are stuck in isolation because it is suspected they have the virus or a family member has it then yes I think it would be of very great value to have them done.
The Head of the English NHS Trusts was on the radio yesterday and said that they had been testing key workers who were stuck at home under 14 day quarantine and found that only 15% of them had the virus. That could make a big difference to workloads on the front line.
Thank you - yes, a good idea to test NHS staff (but even then they could catch the virus the next day). But is there any point doing testing on the likes of my mother in law, who hasn't seen daylight in 14 days'?
Not immediately. But if they can get the antibody tests going and find that a substantial proportion of the population has already had the virus then at that point testing people currently in isolation might mean at least some will be able to ease their restrictions - perhaps not going out as that would confuse matters and make policing it all more difficult but at least receive visitors and helpers without fear of contacting the disease.
Yeah agree 100% with that. The antibody test sounds like the one which will change the landscape dramatically.
I can't see a great deal of point in the standard virus test when you could test negative at 3pm and go out and contract the virus at 4pm!
A widely used and random antibody test might also reset the upper bound of how bad this can get on a population level and how far we are through this. If we can also antibody test a sample for other Coronas on a smaller scale, we might get lucky and find that nobody immune to Corona-A contracted COVID or, if they did, they were invariably asymptomatic. Such co-immunity is known between other Coronas, but that would also change the game drastically.
It does still seem, even operating amongst communities in varying degrees of lockdown, that the upper bound of detected infections seen anywhere has been around 1%. It does feel like we either have asymptomatic cases and/or some prior immunity, else somewhere, some low level locality, would have blown this figure.
The nanny state temperance lobby and its associated cranks never miss an opportunity to push their agenda.
Everyone should judge their own risks and their own circumstances. If you are young, female, reasonably fit with a BMI <25 and no underlying conditions like asthma or diabetes it would probably be an unnecessary precaution. If you tick 3/4 of those boxes likewise. If you don't, like me, you should really think about it.
Its not the nanny state, its common sense. </p>
You described me exactly there David so I can continue supping.
Never doubted it Malcolm. I trust you and your good lady wife are well?
My wife has restarted drinking, not stopped. It's not much, just a glass of wine every now and then, but she drank almost nothing beforehand because I don't drink at all so she always felt guilty doing so. Now she just doesn't care.
Good for her, a few glasses can only be good for you. These halfwits would have you drinking coke and all those other sugary crap drinks that must be much much worse for you than a beer or a glass of wine.
When I'm in the mood I like ale - and there is a need for a celebratory SMT drinkie tomorrow. So I had a look at the local ale link - never heard of the brewery and their prices are £lots.
Then had a look at the amazing Orkney brewery's online shop. Their Dark Isle is the shizzle and as I can't get to a Tesco in Scotland at the moment I'll have a look at getting them to deliver. Its nearly double the Tesco price.
So a trip to Tesco to buy non-Scottish ale it will have to be.
I could not believe he posted that with a straight face - 'Glasto 2017' -ffs
It was an important moment because it was Peak Corbyn. I called it at the time. It felt to me then slightly unreal (albeit rather fabulous) and therefore not sustainable. Like the only way was down. And so it proved.
I wonder if Dec 13th was Peak Boris? It's starting to look that way. Not sure though. He's a hard one to work out.
Interesting timing on the Labour leadership result. We all thought originally that the whole thing was ludicrously drawn out, that Labour would suffer.
Funny though how events in politics have a habit of seizing control. Had Starmer been announced 4 weeks ago I don't think anyone would have paid any attention. They still might not. But this Government is suddenly looking shaky. It's coming under fire from all quarters, including the Right. On cue along comes the most electable Labour leader since Tony Blair.
Yes - how dare the independent give over their opinion column to an academic/nurse specializing in mental health? Who do they think they are?
It's very good advice to reduce your alcohol consumption at the present time. In addition to the links between immune system & alcohol, cutting down on drinking could also help people lose weight, which is associated with bad outcomes if you do get COVID 19.
People should be able to drink or not drink as they wish, we have enough nanny state as it is. Unfortunately I am down to my last 2 bottles of beer, I may need assistance.
malc - the amazing Black Isle brewery beers can be bought online (via flavourly)
Somewhere in the ether I have two crates of Innis & Gunn coming, they are taking their time. I will give blackisle a try. More chance of me becoming the pope than there is of me giving up the drink.
Latest figures log rate per million population. Italy definitely seems to be flattening off. Most countries still on an exponential line regardless of steps taken, but that's no surprise at all when you think about it (the deaths being recorded today were probably from infections around 7th-11th of March. Realistically, only Italy has had enough time since lockdowns for any real effect to be taken. (It would be good for journalists to point out the lag issue at some point)
We're still tracking extremely close to Italy + 15 days. Not sure exactly when our lockdown measures came into place vs theirs, though
It is interesting that Sweden's line is the same as other Countries
Thanks for producing this Andy_Cooke
I don't know how simple it would be, but, is there a way of indicating with a X when on that graph each nation implemented its Lock down?
Not testing frontline HCPs who are symptomatic might be strategy and not due to capacity problems.
If 1 in 4 negative test results are actually wrong (these clinicians actually have Covid19) and the incorrect result means they then go into work with huge numbers of vulnerable patients, then that is very dangerous indeed.
Might be better for them to sit it out and self-isolate for 7 days to be sure.
Perhaps that's what PHE are doing but are reluctant to reveal for obvious reasons. Namely the reaction.. 'what!? the tests are actually wrong!?!!' from the usual idiot crowd.
I think that's why there around 7 people per 10 tests at the moment. Negative results may be double checked.
Yeah but it's not as simple as just doing a double-sample on the same day. The test accuracy will have an important relationship with the timing of symptoms. Serial testing over a number of days for HCPs would be needed. Would 3-4 tests over 3-4 days be worth the potential 3-day time saved for the HCP versus a 7-day sit out? Perhaps, perhaps not. It should be data driven and it probably depends crucially on the point of where we are on the epidemic curve and what current absenteeism is in the local setting.
Complex stuff figuring out how to allocate these resources. Politicians and political pundits are probably not well placed in understanding the necessary subtlety.
Ref the US elections, worth noting that it's quite likely that the number US unemployed has increased by more in the last 2 weeks than through the whole of 1929-33. Certainly, the number will be broadly similar (the current reported figures exclude (1) those who've tried to claim but haven't been able to get through due to the immense number of applications; and (2) those who aren't qualified to claim but are nonetheless unemployed).
Of course, the US is a much more populous country now than it was in the 1930s. On the other hand, 2 weeks is a lot less than 4 years.
What makes it even more astonishing is that the US stock markets haven't plummeted - in fact they are a smidgen up.
If the govt went out and did 100k random tests tomorrow and 95% came back negative, wouldn't that be a waste of time/resources?
Given the 40%+ positive figures, it appears that testing is being done only on suspected cases. Which makes more sense to me.
I can't see the point in testing millions of people who've been stuck at home for a fortnight (NHS workers aside) knowing that when they emerge back outdoors they are going to get it anyway.
Surely the only positive thing a govt can do is play for time to help the NHS. They are resigned to the fact 80%+ of us will get the illness and are doing this lockdown to try to stagger it. Testing won't stop people getting it.
If those 100,000 tests were of key workers who are stuck in isolation because it is suspected they have the virus or a family member has it then yes I think it would be of very great value to have them done.
The Head of the English NHS Trusts was on the radio yesterday and said that they had been testing key workers who were stuck at home under 14 day quarantine and found that only 15% of them had the virus. That could make a big difference to workloads on the front line.
Thank you - yes, a good idea to test NHS staff (but even then they could catch the virus the next day). But is there any point doing testing on the likes of my mother in law, who hasn't seen daylight in 14 days'?
Not immediately. But if they can get the antibody tests going and find that a substantial proportion of the population has already had the virus then at that point testing people currently in isolation might mean at least some will be able to ease their restrictions - perhaps not going out as that would confuse matters and make policing it all more difficult but at least receive visitors and helpers without fear of contacting the disease.
Yeah agree 100% with that. The antibody test sounds like the one which will change the landscape dramatically.
I can't see a great deal of point in the standard virus test when you could test negative at 3pm and go out and contract the virus at 4pm!
A widely used and random antibody test might also reset the upper bound of how bad this can get on a population level and how far we are through this. If we can also antibody test a sample for other Coronas on a smaller scale, we might get lucky and find that nobody immune to Corona-A contracted COVID or, if they did, they were invariably asymptomatic. Such co-immunity is known between other Coronas, but that would also change the game drastically.
Can you provide a link for co-immunity for other coronaviruses?
It would be great to see Italy's fatality figure fall below the UK's today...and will give us a boost that the lockdown is working...we are probably a couple of days from crossover though
Not testing frontline HCPs who are symptomatic might be strategy and not due to capacity problems.
If 1 in 4 negative test results are actually wrong (these clinicians actually have Covid19) and the incorrect result means they then go into work with huge numbers of vulnerable patients, then that is very dangerous indeed.
Might be better for them to sit it out and self-isolate for 7 days to be sure.
Perhaps that's what PHE are doing but are reluctant to reveal for obvious reasons. Namely the reaction.. 'what!? the tests are actually wrong!?!!' from the usual idiot crowd.
I think that's why there around 7 people per 10 tests at the moment. Negative results may be double checked.
Not testing frontline HCPs who are symptomatic might be strategy and not due to capacity problems.
If 1 in 4 negative test results are actually wrong (these clinicians actually have Covid19) and the incorrect result means they then go into work with huge numbers of vulnerable patients, then that is very dangerous indeed.
Might be better for them to sit it out and self-isolate for 7 days to be sure.
Perhaps that's what PHE are doing but are reluctant to reveal for obvious reasons. Namely the reaction.. 'what!? the tests are actually wrong!?!!' from the usual idiot crowd.
This was why I was trying to find a scientific answer to the 2 questions...
1) What is the accuracy of the current test? 2) What is the accuracy of diagnosis via symptoms?
It might actually be the case that diagnosis is better than the test....
Sitting it out for 7 days will be more sensitive than the PCR-test. But it won't be as specific. There will be many sitting it out unnecessarily but we will catch the vast majority of Covid19 positives.
However, the utility function in my view is weighted more towards avoiding false negatives rather than false-positives. When hospitals are running with 1/3 of the staff then that equation might shift the other way.
I could not believe he posted that with a straight face - 'Glasto 2017' -ffs
It was an important moment because it was Peak Corbyn. I called it at the time. It felt to me then slightly unreal (albeit rather fabulous) and therefore not sustainable. Like the only way was down. And so it proved.
I wonder if Dec 13th was Peak Boris? It's starting to look that way. Not sure though. He's a hard one to work out.
Notwithstanding understandable uphoria at what had been an unexpectedly good result in 2017, and thus the relative vindication of the Corbynite faction (even though it was not a win), that sort of thing was where adulation got a bit creepy.
Dec 13th is a good bet for peak Boris, if one assumes a rallying effect now is limited and he'll struggle to do the things he had otherwise planned.
I could not believe he posted that with a straight face - 'Glasto 2017' -ffs
It was an important moment because it was Peak Corbyn. I called it at the time. It felt to me then slightly unreal (albeit rather fabulous) and therefore not sustainable. Like the only way was down. And so it proved.
I wonder if Dec 13th was Peak Boris? It's starting to look that way. Not sure though. He's a hard one to work out.
Possibly but then that's true for most politicians. Peak Tony Blair was 1/5/97 and for any politician their peak being winning a landslide is presumably better than peaking at being popular at Glastonbury.
Not testing frontline HCPs who are symptomatic might be strategy and not due to capacity problems.
If 1 in 4 negative test results are actually wrong (these clinicians actually have Covid19) and the incorrect result means they then go into work with huge numbers of vulnerable patients, then that is very dangerous indeed.
Might be better for them to sit it out and self-isolate for 7 days to be sure.
Perhaps that's what PHE are doing but are reluctant to reveal for obvious reasons. Namely the reaction.. 'what!? the tests are actually wrong!?!!' from the usual idiot crowd.
I thought that the test where more lickly to give a false Positive, and 'relatively' unlikely to give a false negative, have I got that the wrong way around?
But overall I agree with your assessment, Lots of testing a month ago, would have allowed, South Korean Steal, 'test, track and test' and therefor keep infection down and no need for a lock down. but at this stage with 4,000 people a day being identified, how we would track that many people is probably not practical.
Not testing fromntline HCPs who are symptomatic might be strategy and not due to capacity problems.
If 1 in 4 negative test results are actually wrong (these clinicians actually have Covid19) and the incorrect result means they then go into work with huge numbers of vulnerable patients, then that is very dangerous indeed.
Might be better for them to sit it out and self-isolate for 7 days to be sure.
Perhaps that's what PHE are doing but are reluctant to reveal for obvious reasons. Namely the reaction.. 'what!? the tests are actually wrong!?!!' from the usual idiot crowd.
This was why I was trying to find a scientific answer to the 2 questions...
1) What is the accuracy of the current test? 2) What is the accuracy of diagnosis via symptoms?
It might actually be the case that diagnosis is better than the test....
Sitting it out for 7 days will be more sensitive than the PCR-test. But it won't be as specific. There will be many sitting it out unnecessarily but we will catch the vast majority of Covid19 positives.
However, the utility function in my view is weighted more towards avoiding false negatives rather than false-positives. When hospitals are running with 1/3 of the staff then that equation might shift the other way.
I agree.
Also if NHS staff are isolating unnecessarily (in that they don't have COVID-19) but may have another virus with similar symptoms instead then its presumably still a good idea for them to isolate.
Probably not a good idea to bring them back in to work to pass the alternative virus around even if it isn't COVID-19 causing other people to develop symptoms.
Not testing frontline HCPs who are symptomatic might be strategy and not due to capacity problems.
If 1 in 4 negative test results are actually wrong (these clinicians actually have Covid19) and the incorrect result means they then go into work with huge numbers of vulnerable patients, then that is very dangerous indeed.
Might be better for them to sit it out and self-isolate for 7 days to be sure.
Perhaps that's what PHE are doing but are reluctant to reveal for obvious reasons. Namely the reaction.. 'what!? the tests are actually wrong!?!!' from the usual idiot crowd.
I think that's why there around 7 people per 10 tests at the moment. Negative results may be double checked.
My back of envelope R0 measure (new cases announced 31/3- 2/4 ÷ those announced 24-26/3) now at 2.31, down from 2.58 yesterday, and 3.25 at the beginning of this week.
On reporting date we're into post lockdown figures now, but on average a case reported on 24/3 will have onward infected most people before that date, and I'd be pretty sure onward infection time isn't as tightly distributed around 7 days as my measure allows for. I still expect my R0 to fall substantially in the next few days.
I suppose you mean R, seeing that R0 is the reproduction number in the absence of any interventions to reduce the spread.
But how anyone thinks they can calculate anything relating to the real spread of the virus from such wholly inadequate data - let alone daily changes (?!?) is beyond me.
Actually this is somewhere that people aren't totally consistent on terminology. Some people use R0 to mean "the reproduction number when there is no immunity from past exposures or vaccination, nor any deliberate intervention in disease transmission" (see eg this Australian government document which is worth a read for anyone who's interested in the modelling side - it's from a very accessible report entitled "Using Mathematical Models to Assess Responses to an Outbreak of an Emerged Viral Respiratory Disease").
What everyone is universally agreed on is that R0 only applies in a completely susceptible population. So if you reduce the proportion who are susceptible (whether by a vaccination campaign or by people who recover from the disease gaining immunity) then the net or effective reproduction number will be lower: R = s R0 where s is the proportion who are susceptible.
But if population A and population B have different age structures and/or different contact patterns, then the same disease will have a different R0 in the two populations. The thing that gets a bit dodgy is when population A and population B are really the same people, but behaving differently eg due to government intervention. Some people will say the R0 is the same but the R has changed due to the intervention. Other people will say it's the R0 that's changed, and reserve changes in R for when the proportion susceptible changes too - plenty of professional epidemiologists will maintain that distinction (the link goes to a recent LSHTM study who estimated the reduction of contacts in survey data would be sufficient to "reduce R0 from a value from 2.6 before the lockdown to 0.62 (0.37 - 0.89) during the lockdown", where clearly they view the intervention and subsequent behavioural change as altering R0 itself).
Latest figures log rate per million population. Italy definitely seems to be flattening off. Most countries still on an exponential line regardless of steps taken, but that's no surprise at all when you think about it (the deaths being recorded today were probably from infections around 7th-11th of March. Realistically, only Italy has had enough time since lockdowns for any real effect to be taken. (It would be good for journalists to point out the lag issue at some point)
We're still tracking extremely close to Italy + 15 days. Not sure exactly when our lockdown measures came into place vs theirs, though
It is interesting that Sweden's line is the same as other Countries
Why is that interesting? Which of the other countries had a lockdown in place early enough to be reducing deaths by that point in their line?
China?
Is not depicted on that graph
Chinas depiected on other graphs down thread
and despite all the evidence that is now coming to light you actually believe China's figures? You wouldn't happen to interested in a bridge I have for sale?
Not testing frontline HCPs who are symptomatic might be strategy and not due to capacity problems.
If 1 in 4 negative test results are actually wrong (these clinicians actually have Covid19) and the incorrect result means they then go into work with huge numbers of vulnerable patients, then that is very dangerous indeed.
Might be better for them to sit it out and self-isolate for 7 days to be sure.
Perhaps that's what PHE are doing but are reluctant to reveal for obvious reasons. Namely the reaction.. 'what!? the tests are actually wrong!?!!' from the usual idiot crowd.
I thought that the test where more lickly to give a false Positive, and 'relatively' unlikely to give a false negative, have I got that the wrong way around?
But overall I agree with your assessment, Lots of testing a month ago, would have allowed, South Korean Steal, 'test, track and test' and therefor keep infection down and no need for a lock down. but at this stage with 4,000 people a day being identified, how we would track that many people is probably not practical.
As I understand it, the issue is not the test itself - the issue is getting a good swab from the patient. The actual test is accurate, but false negatives occur because the swabs have not collected enough virus laden material.
So the false positive problem is miniscule - but the chances of a false negative are much higher.
Latest figures log rate per million population. Italy definitely seems to be flattening off. Most countries still on an exponential line regardless of steps taken, but that's no surprise at all when you think about it (the deaths being recorded today were probably from infections around 7th-11th of March. Realistically, only Italy has had enough time since lockdowns for any real effect to be taken. (It would be good for journalists to point out the lag issue at some point)
We're still tracking extremely close to Italy + 15 days. Not sure exactly when our lockdown measures came into place vs theirs, though
It is interesting that Sweden's line is the same as other Countries
Well, yes. Most of the deaths currently will be from infections on 7th-11th of March, when most countries didn't have many steps yet taken.
Just imagine how different the situation would be if there were some random testing going on in these countries, so that we weren't just blundering around in the dark guessing about how many cases there really were, or waiting for changes in the death statistics, which lag several weeks behind.
I wonder - can people not see that kind of information would actually enable countries not so far along the curve to make sensible, evidence-based decisions, and might enable hundreds of thousands, if not millions of lives to be saved?
There is already a lot of learning going on....Italy was unlucky with Lombardy..it sat on the first European hotspot and made unfortunate mistakes not knowing any better....
On the other hand we have made huge mistakes knowing what happened in Lombardy...lack of testing, delaying social distancing, failure to get PPE to the right spots....and if we get to 1000 a day fatalities images like running crowded tubes, Cheltenham and the Stereophonics concerts will come back to haunt us...
Not testing frontline HCPs who are symptomatic might be strategy and not due to capacity problems.
If 1 in 4 negative test results are actually wrong (these clinicians actually have Covid19) and the incorrect result means they then go into work with huge numbers of vulnerable patients, then that is very dangerous indeed.
Might be better for them to sit it out and self-isolate for 7 days to be sure.
Perhaps that's what PHE are doing but are reluctant to reveal for obvious reasons. Namely the reaction.. 'what!? the tests are actually wrong!?!!' from the usual idiot crowd.
I thought that the test where more lickly to give a false Positive, and 'relatively' unlikely to give a false negative, have I got that the wrong way around?
But overall I agree with your assessment, Lots of testing a month ago, would have allowed, South Korean Steal, 'test, track and test' and therefor keep infection down and no need for a lock down. but at this stage with 4,000 people a day being identified, how we would track that many people is probably not practical.
Other way round. If you think about the process involved there is a decent chance that the swabbing technique around the mouth and throat doesn't catch the virus - false negative. Moreover, Covid19 impacts more on the lower respiratory tract whereas swabbing grabs material from the upper respiratory tract.
On the other hand, there is a low chance of finding evidence of the virus without it actually being there - false positive. It's not like it's a normal biomarker that you always have in your body.
I would give some blame to those who went along, although the Government should've been stricter and banned it. Government action or inaction doesn't wholly absolve individuals of personal responsibility.
Not testing fromntline HCPs who are symptomatic might be strategy and not due to capacity problems.
If 1 in 4 negative test results are actually wrong (these clinicians actually have Covid19) and the incorrect result means they then go into work with huge numbers of vulnerable patients, then that is very dangerous indeed.
Might be better for them to sit it out and self-isolate for 7 days to be sure.
Perhaps that's what PHE are doing but are reluctant to reveal for obvious reasons. Namely the reaction.. 'what!? the tests are actually wrong!?!!' from the usual idiot crowd.
This was why I was trying to find a scientific answer to the 2 questions...
1) What is the accuracy of the current test? 2) What is the accuracy of diagnosis via symptoms?
It might actually be the case that diagnosis is better than the test....
Sitting it out for 7 days will be more sensitive than the PCR-test. But it won't be as specific. There will be many sitting it out unnecessarily but we will catch the vast majority of Covid19 positives.
However, the utility function in my view is weighted more towards avoiding false negatives rather than false-positives. When hospitals are running with 1/3 of the staff then that equation might shift the other way.
I agree.
Also if NHS staff are isolating unnecessarily (in that they don't have COVID-19) but may have another virus with similar symptoms instead then its presumably still a good idea for them to isolate.
Probably not a good idea to bring them back in to work to pass the alternative virus around even if it isn't COVID-19 causing other people to develop symptoms.
Exactly. It means everyone they infect with Not Covid still has to get tested to see if they are Not Covid too.
Pesumably a sign of how close to the wire the NHS is working that they would rather have folk back doing something, rather than not have them on the ward at all.
I think we should probably have done the same as Sweden.
From the article:
"This Swedish exceptionalism is about principle, not epidemiology. It’s true that we’re perhaps less at risk due to our high rate of single-person households and low number of smokers. Closing the schools would, as well, have a bigger impact in a country where almost all mums are working mums. But frankly, all these explanations miss the point: yes, they make us different to Italy and Spain, but not to Denmark, Finland and Norway. Sweden simply made the call to take measures that don’t destroy the free society."
The frustration comes when you see people using the current death rates to "prove" that the shutdown has no effect...
Head. Desk.
Yes that is virus 101. People not mixing HAS to slow the spread of an infectious disease. If it doesn't we would be looking at something rather unthinkable.
My back of envelope R0 measure (new cases announced 31/3- 2/4 ÷ those announced 24-26/3) now at 2.31, down from 2.58 yesterday, and 3.25 at the beginning of this week.
On reporting date we're into post lockdown figures now, but on average a case reported on 24/3 will have onward infected most people before that date, and I'd be pretty sure onward infection time isn't as tightly distributed around 7 days as my measure allows for. I still expect my R0 to fall substantially in the next few days.
I suppose you mean R, seeing that R0 is the reproduction number in the absence of any interventions to reduce the spread.
But how anyone thinks they can calculate anything relating to the real spread of the virus from such wholly inadequate data - let alone daily changes (?!?) is beyond me.
Actually this is somewhere that people aren't totally consistent on terminology. Some people use R0 to mean "the reproduction number when there is no immunity from past exposures or vaccination, nor any deliberate intervention in disease transmission" (see eg this Australian government document which is worth a read for anyone who's interested in the modelling side - it's from a very accessible report entitled "Using Mathematical Models to Assess Responses to an Outbreak of an Emerged Viral Respiratory Disease").
What everyone is universally agreed on is that R0 only applies in a completely susceptible population. So if you reduce the proportion who are susceptible (whether by a vaccination campaign or by people who recover from the disease gaining immunity) then the net or effective reproduction number will be lower: R = s R0 where s is the proportion who are susceptible.
But if population A and population B have different age structures and/or different contact patterns, then the same disease will have a different R0 in the two populations. The thing that gets a bit dodgy is when population A and population B are really the same people, but behaving differently eg due to government intervention. Some people will say the R0 is the same but the R has changed due to the intervention. Other people will say it's the R0 that's changed, and reserve changes in R for when the proportion susceptible changes too - plenty of professional epidemiologists will maintain that distinction (the link goes to a recent LSHTM study who estimated the reduction of contacts in survey data would be sufficient to "reduce R0 from a value from 2.6 before the lockdown to 0.62 (0.37 - 0.89) during the lockdown", where clearly they view the intervention and subsequent behavioural change as altering R0 itself).
Whereas this Imperial study released the day before looks at death data to estimate how reproduction has changed over time, and focuses on Rt (time-varying effective reproduction number). Which is broadly what @Pro_Rata was trying to do but in a more statistically-informed way!
If the govt went out and did 100k random tests tomorrow and 95% came back negative, wouldn't that be a waste of time/resources?
Given the 40%+ positive figures, it appears that testing is being done only on suspected cases. Which makes more sense to me.
I can't see the point in testing millions of people who've been stuck at home for a fortnight (NHS workers aside) knowing that when they emerge back outdoors they are going to get it anyway.
Surely the only positive thing a govt can do is play for time to help the NHS. They are resigned to the fact 80%+ of us will get the illness and are doing this lockdown to try to stagger it. Testing won't stop people getting it.
If those 100,000 tests were of key workers who are stuck in isolation because it is suspected they have the virus or a family member has it then yes I think it would be of very great value to have them done.
The Head of the English NHS Trusts was on the radio yesterday and said that they had been testing key workers who were stuck at home under 14 day quarantine and found that only 15% of them had the virus. That could make a big difference to workloads on the front line.
Thank you - yes, a good idea to test NHS staff (but even then they could catch the virus the next day). But is there any point doing testing on the likes of my mother in law, who hasn't seen daylight in 14 days'?
Not immediately. But if they can get the antibody tests going and find that a substantial proportion of the population has already had the virus then at that point testing people currently in isolation might mean at least some will be able to ease their restrictions - perhaps not going out as that would confuse matters and make policing it all more difficult but at least receive visitors and helpers without fear of contacting the disease.
Yeah agree 100% with that. The antibody test sounds like the one which will change the landscape dramatically.
I can't see a great deal of point in the standard virus test when you could test negative at 3pm and go out and contract the virus at 4pm!
A widely used and random antibody test might also reset the upper bound of how bad this can get on a population level and how far we are through this. If we can also antibody test a sample for other Coronas on a smaller scale, we might get lucky and find that nobody immune to Corona-A contracted COVID or, if they did, they were invariably asymptomatic. Such co-immunity is known between other Coronas, but that would also change the game drastically.
Can you provide a link for co-immunity for other coronaviruses?
I can't find where I originally read this - it was in one of the US explainers , and I recall it as cross-immunity between mild forms OC43 and 229E. However, the paper I've found today found no.link.
I suspect from the few results I can see, that the science here is not fully established and maybe I'm adding 2+2 a bit in thinking something is at play and here is a candidate something.
Never feel TOO guilty about not posting an Owen Jones article.
So the left`s pressure to lockdown, with the costs that that was bound to entail, will transform into a new Labour Party narrative that getting county`s finances in the direction of sanity post-virus will amount to Tory Austerity Mark2.
My back of envelope R0 measure (new cases announced 31/3- 2/4 ÷ those announced 24-26/3) now at 2.31, down from 2.58 yesterday, and 3.25 at the beginning of this week.
On reporting date we're into post lockdown figures now, but on average a case reported on 24/3 will have onward infected most people before that date, and I'd be pretty sure onward infection time isn't as tightly distributed around 7 days as my measure allows for. I still expect my R0 to fall substantially in the next few days.
I suppose you mean R, seeing that R0 is the reproduction number in the absence of any interventions to reduce the spread.
But how anyone thinks they can calculate anything relating to the real spread of the virus from such wholly inadequate data - let alone daily changes (?!?) is beyond me.
Actually this is somewhere that people aren't totally consistent on terminology. Some people use R0 to mean "the reproduction number when there is no immunity from past exposures or vaccination, nor any deliberate intervention in disease transmission" (see eg this Australian government document which is worth a read for anyone who's interested in the modelling side - it's from a very accessible report entitled "Using Mathematical Models to Assess Responses to an Outbreak of an Emerged Viral Respiratory Disease").
What everyone is universally agreed on is that R0 only applies in a completely susceptible population. So if you reduce the proportion who are susceptible (whether by a vaccination campaign or by people who recover from the disease gaining immunity) then the net or effective reproduction number will be lower: R = s R0 where s is the proportion who are susceptible.
But if population A and population B have different age structures and/or different contact patterns, then the same disease will have a different R0 in the two populations. The thing that gets a bit dodgy is when population A and population B are really the same people, but behaving differently eg due to government intervention. Some people will say the R0 is the same but the R has changed due to the intervention. Other people will say it's the R0 that's changed, and reserve changes in R for when the proportion susceptible changes too - plenty of professional epidemiologists will maintain that distinction (the link goes to a recent LSHTM study who estimated the reduction of contacts in survey data would be sufficient to "reduce R0 from a value from 2.6 before the lockdown to 0.62 (0.37 - 0.89) during the lockdown", where clearly they view the intervention and subsequent behavioural change as altering R0 itself).
Whereas this Imperial study released the day before looks at death data to estimate how reproduction has changed over time, and focuses on Rt (time-varying effective reproduction number). Which is broadly what @Pro_Rata was trying to do but in a more statistically-informed way!
Please stop discussing matters in a scientific, intelligent manner. Your are raising the tone of the whole internet in an unacceptable manner. Please send some tweets in ALL CAPS immediately to make up for it,
Why is that chilling reading? I didn't find it so. It's an interesting insight into why the Swedes are (for now) taking a different approach to most countries.
Shortly we will hear that armed police have deployed to kill the goat menace.
When wild boar escaped in Wiltshire, a good while ago, plod discovered that 9mm doesn't impress boar. More like mildly irritates. So they tried to borrow firearms from a local hunter. Who they had harassed about his hunting weapons non-stop for years....
Why is that chilling reading? I didn't find it so. It was an interesting insight into why the Swedes are (for now) taking a different approach to most countries.
Chilling in that I think they may have made the right decision, we have not and there is going to be huge consequences for us.
Not testing frontline HCPs who are symptomatic might be strategy and not due to capacity problems.
If 1 in 4 negative test results are actually wrong (these clinicians actually have Covid19) and the incorrect result means they then go into work with huge numbers of vulnerable patients, then that is very dangerous indeed.
Might be better for them to sit it out and self-isolate for 7 days to be sure.
Perhaps that's what PHE are doing but are reluctant to reveal for obvious reasons. Namely the reaction.. 'what!? the tests are actually wrong!?!!' from the usual idiot crowd.
I thought that the test where more lickly to give a false Positive, and 'relatively' unlikely to give a false negative, have I got that the wrong way around?
But overall I agree with your assessment, Lots of testing a month ago, would have allowed, South Korean Steal, 'test, track and test' and therefor keep infection down and no need for a lock down. but at this stage with 4,000 people a day being identified, how we would track that many people is probably not practical.
Other way round. If you think about the process involved there is a decent chance that the swabbing technique around the mouth and throat doesn't catch the virus - false negative. Moreover, Covid19 impacts more on the lower respiratory tract whereas swabbing grabs material from the upper respiratory tract.
On the other hand, there is a low chance of finding evidence of the virus without it actually being there - false positive. It's not like it's a normal biomarker that you always have in your body.
@Foxy suggested a false negative rate of circa 25% a while back. Not sure where he got this from.
The Oxford Centre for Evidence-Based Medicine did a literature review a few days ago and found that there was only poor quality evidence available re the accuracy of oropharyngeal versus nasopharyngeal swabs for COVID-19, and it was not possible to accurately assess or compare their sensitivity, nor figure out what the effect might be of combining the two methods... I can understand why PHE is working very hard on "getting testing right". Would be a nightmare for them to end up with building an entire testing infrastructure around a testing procedure that's worse than useless (as has been pointed out downthread, false negatives in the healthcare worker context are particularly dangerous).
Re false positives, there was a Chinese paper suggesting there were issues when people lived in the same space as someone who was infected - you might find RNA from viruses that got in the nose etc but hadn't actually caused an infection. This got a bit of an airing on PB but the paper was later withdrawn. https://pubmed.ncbi.nlm.nih.gov/32133832/
Shortly we will hear that armed police have deployed to kill the goat menace.
When wild boar escaped in Wiltshire, a good while ago, plod discovered that 9mm doesn't impress boar. More like mildly irritates. So they tried to borrow firearms from a local hunter. Who they had harassed about his hunting weapons non-stop for years....
The goats will not be shot, believe me I live in Llandudno
My back of envelope R0 measure (new cases announced 31/3- 2/4 ÷ those announced 24-26/3) now at 2.31, down from 2.58 yesterday, and 3.25 at the beginning of this week.
On reporting date we're into post lockdown figures now, but on average a case reported on 24/3 will have onward infected most people before that date, and I'd be pretty sure onward infection time isn't as tightly distributed around 7 days as my measure allows for. I still expect my R0 to fall substantially in the next few days.
I suppose you mean R, seeing that R0 is the reproduction number in the absence of any interventions to reduce the spread.
But how anyone thinks they can calculate anything relating to the real spread of the virus from such wholly inadequate data - let alone daily changes (?!?) is beyond me.
Actually this is somewhere that people aren't totally consistent on terminology. Some people use R0 to mean "the reproduction number when there is no immunity from past exposures or vaccination, nor any deliberate intervention in disease transmission" (see eg this Australian government document which is worth a read for anyone who's interested in the modelling side - it's from a very accessible report entitled "Using Mathematical Models to Assess Responses to an Outbreak of an Emerged Viral Respiratory Disease").
What everyone is universally agreed on is that R0 only applies in a completely susceptible population. So if you reduce the proportion who are susceptible (whether by a vaccination campaign or by people who recover from the disease gaining immunity) then the net or effective reproduction number will be lower: R = s R0 where s is the proportion who are susceptible.
But if population A and population B have different age structures and/or different contact patterns, then the same disease will have a different R0 in the two populations. The thing that gets a bit dodgy is when population A and population B are really the same people, but behaving differently eg due to government intervention. Some people will say the R0 is the same but the R has changed due to the intervention. Other people will say it's the R0 that's changed, and reserve changes in R for when the proportion susceptible changes too - plenty of professional epidemiologists will maintain that distinction (the link goes to a recent LSHTM study who estimated the reduction of contacts in survey data would be sufficient to "reduce R0 from a value from 2.6 before the lockdown to 0.62 (0.37 - 0.89) during the lockdown", where clearly they view the intervention and subsequent behavioural change as altering R0 itself).
And also populations modify their own behaviour in response to emerging disease, of course.
I can think of various drugs prescribed and recreational where cold turkey will have very nasty effects on the taker. I'm pretty sure smackheads would consider collection of their hit to be essential. And their dealer wasn't explicitly included on the government shutdown list despite coke and hookers having years ago been counted as economic output...
Government approval is like leader approval, my general assumption is it's damn rare to be positive, I wonder the last time it was and what was special about that time.
Shortly we will hear that armed police have deployed to kill the goat menace.
When wild boar escaped in Wiltshire, a good while ago, plod discovered that 9mm doesn't impress boar. More like mildly irritates. So they tried to borrow firearms from a local hunter. Who they had harassed about his hunting weapons non-stop for years....
The goats will not be shot, believe me I live in Llandudno
The seagulls are more of an issue
It depends on the nature of your armed police. I once encountered a policeman who thought walking across a private field with a broken shotgun (in the company of the farmer) in the crook of your arm was "menacing the public".
Fortunately another armed plod arrived about 30 seconds later and told him to stop being a twat.
Why is that chilling reading? I didn't find it so. It's an interesting insight into why the Swedes are (for now) taking a different approach to most countries.
Certainly it cannot simply be assumed that doing things differently must be wrong, it's why claims (with that as the reason) we did not act correctly first up was unfair (though actions could still be wrong for other reasons rather than due to an expection of, ahem, herding)
Government approval is like leader approval, my general assumption is it's damn rare to be positive, I wonder the last time it was and what was special about that time.
Shortly we will hear that armed police have deployed to kill the goat menace.
When wild boar escaped in Wiltshire, a good while ago, plod discovered that 9mm doesn't impress boar. More like mildly irritates. So they tried to borrow firearms from a local hunter. Who they had harassed about his hunting weapons non-stop for years....
I have vague recollections of stories in the local press about wild boar a few years ago. I expect people were surprised to discover they exist outside of Asterix comics.
I think we should probably have done the same as Sweden.
From the article:
"This Swedish exceptionalism is about principle, not epidemiology. It’s true that we’re perhaps less at risk due to our high rate of single-person households and low number of smokers. Closing the schools would, as well, have a bigger impact in a country where almost all mums are working mums. But frankly, all these explanations miss the point: yes, they make us different to Italy and Spain, but not to Denmark, Finland and Norway. Sweden simply made the call to take measures that don’t destroy the free society."
Interesting line towards the end about expecting higher deaths (in the near future) than other locked down countries, but "still all within the confines of a bad winter flu". If that turns out to be true then Sweden will have made the right call (from an economics/deaths perspective - the libertarian perspective is a different issue for which 'right' depends on values more than numbers) but that's not something that we know yet. If fatality rate is 1% (it may turn out to be much lower, when we know more) then it will likely be a lot worse than bad winter flu, depending how many get infected.
Having been in Sweden extensively during my PhD in the two main cities, including for a continuous period of two months - and knowing a number of people there, although mostly among the urban professional classes - I do think the people there will be mostly listening to the advice and doing social distancing, without being compelled to do so. So they may do plenty of their own curve flattening without a full lockdown. From an epidemiological perspective, it will be fascinating to see. From a humanitarian perspective, I hope it will not be too distressing to see.
A good friend's best friend just died of the virus in New York. She was 48.
Somebody else the Wife knows extremely well has it. She won't be put on a ventilator, as she is too old.
Shit got real.
An interesting day back at work. We now have 122 confirmed Covid19 patients as inpatients. 22 fatalities (to yesterday) 38 discharged home.
Thanks for the update @Foxy! If you're allowed to say, are all of the 62 'active' cases in the ICU?
122 active cases, not counting in my figures resolved cases. Currently increasing about 20% per day. Most are on medical wards. ICU only taking those with good Clinical Frailty Scores.
Looking at table 2, we see that out of 50 patients admitted to ICU (representing 26% of all inpatients so perhaps not far different to the situation chez Foxy) there were only 11 survivors (22%) compared to 39 deaths (78%). All three who received ECMO died; 31 out of the 32 who received invasive mechanical ventilation died; 24 out of the 26 who received non-invasive mechanical ventilation died; 33 of the 41 who received high-flow nasal cannula oxygen therapy died. The median ICU stay was 8 days (IQR from 4 to 12) for those who died and 7 days (IQR from 2 to 9) for those who survived.
Volunteers working at the NHS Nightingale coronavirus hospital have been told to prepare for the fact that up to 80 per cent of patients who are on ventilators will die, MailOnline can reveal.
Selfless heroes flocking to staff the emergency 4,000-bed unit in east London have been told to 'be prepared to see death', with a mortality rate of 50 to 80 per cent among those on ventilators.
Are there any reasons to be more optimistic than those Wuhan stats suggest? If the Mail report is accurate (and whenever you write a sentence that starts like that about a medical story, you know the "if" deserves red flashing fairy lights around it, but this one sounds plausible) then it doesn't sound like the top brass are very hopeful.
Government approval is like leader approval, my general assumption is it's damn rare to be positive, I wonder the last time it was and what was special about that time.
Cheers. I'm a little surprised the tailend of the Labour government, admittedly after a long time in power, was not that far above the nadir of the Brexit argument period.
Shortly we will hear that armed police have deployed to kill the goat menace.
When wild boar escaped in Wiltshire, a good while ago, plod discovered that 9mm doesn't impress boar. More like mildly irritates. So they tried to borrow firearms from a local hunter. Who they had harassed about his hunting weapons non-stop for years....
I have vague recollections of stories in the local press about wild boar a few years ago. I expect people were surprised to discover they exist outside of Asterix comics.
In my experience, they're very shy. There are quite a lot of them around the area where I have my house in Hungary. You see deer regularly. You very rarely see wild boar - except when the hunters bring them back.
Agreed entirely. Fortunately a lot is going on here (numerous clinical trials ongoing) with many existing drugs being repositioned to target this virus.
Shortly we will hear that armed police have deployed to kill the goat menace.
When wild boar escaped in Wiltshire, a good while ago, plod discovered that 9mm doesn't impress boar. More like mildly irritates. So they tried to borrow firearms from a local hunter. Who they had harassed about his hunting weapons non-stop for years....
The goats will not be shot, believe me I live in Llandudno
The seagulls are more of an issue
It depends on the nature of your armed police. I once encountered a policeman who thought walking across a private field with a broken shotgun (in the company of the farmer) in the crook of your arm was "menacing the public".
Fortunately another armed plod arrived about 30 seconds later and told him to stop being a twat.
Got to be a good shot to kill a seagull. Unless it was a sitting bird, and that wouldn't be sporting, would it? Dashed bad form!
Shortly we will hear that armed police have deployed to kill the goat menace.
When wild boar escaped in Wiltshire, a good while ago, plod discovered that 9mm doesn't impress boar. More like mildly irritates. So they tried to borrow firearms from a local hunter. Who they had harassed about his hunting weapons non-stop for years....
I have vague recollections of stories in the local press about wild boar a few years ago. I expect people were surprised to discover they exist outside of Asterix comics.
They are very tasty to eat - hence the farming.
Their personalities are a bit like that bloke from the pub that everyone gives a wide birth to. Normally fine, but can be a bit of nutter when they get upset with something.
Hence they escape due to shear persistency in attacking things like fences.
Stopping them requires a cannon - a big game rifle....
My back of envelope R0 measure (new cases announced 31/3- 2/4 ÷ those announced 24-26/3) now at 2.31, down from 2.58 yesterday, and 3.25 at the beginning of this week.
On reporting date we're into post lockdown figures now, but on average a case reported on 24/3 will have onward infected most people before that date, and I'd be pretty sure onward infection time isn't as tightly distributed around 7 days as my measure allows for. I still expect my R0 to fall substantially in the next few days.
I suppose you mean R, seeing that R0 is the reproduction number in the absence of any interventions to reduce the spread.
But how anyone thinks they can calculate anything relating to the real spread of the virus from such wholly inadequate data - let alone daily changes (?!?) is beyond me.
Actually this is somewhere that people aren't totally consistent on terminology. Some people use R0 to mean "the reproduction number when there is no immunity from past exposures or vaccination, nor any deliberate intervention in disease transmission" (see eg this Australian government document which is worth a read for anyone who's interested in the modelling side - it's from a very accessible report entitled "Using Mathematical Models to Assess Responses to an Outbreak of an Emerged Viral Respiratory Disease").
What everyone is universally agreed on is that R0 only applies in a completely susceptible population. So if you reduce the proportion who are susceptible (whether by a vaccination campaign or by people who recover from the disease gaining immunity) then the net or effective reproduction number will be lower: R = s R0 where s is the proportion who are susceptible.
But if population A and population B have different age structures and/or different contact patterns, then the same disease will have a different R0 in the two populations. The thing that gets a bit dodgy is when population A and population B are really the same people, but behaving differently eg due to government intervention. Some people will say the R0 is the same but the R has changed due to the intervention. Other people will say it's the R0 that's changed, and reserve changes in R for when the proportion susceptible changes too - plenty of professional epidemiologists will maintain that distinction (the link goes to a recent LSHTM study who estimated the reduction of contacts in survey data would be sufficient to "reduce R0 from a value from 2.6 before the lockdown to 0.62 (0.37 - 0.89) during the lockdown", where clearly they view the intervention and subsequent behavioural change as altering R0 itself).
Whereas this Imperial study released the day before looks at death data to estimate how reproduction has changed over time, and focuses on Rt (time-varying effective reproduction number). Which is broadly what @Pro_Rata was trying to do but in a more statistically-informed way!
Please stop discussing matters in a scientific, intelligent manner. Your are raising the tone of the whole internet in an unacceptable manner. Please send some tweets in ALL CAPS immediately to make up for it,
And I want to see at least TWO exclamation marks at all times!!!
I think we should probably have done the same as Sweden.
From the article:
"This Swedish exceptionalism is about principle, not epidemiology. It’s true that we’re perhaps less at risk due to our high rate of single-person households and low number of smokers. Closing the schools would, as well, have a bigger impact in a country where almost all mums are working mums. But frankly, all these explanations miss the point: yes, they make us different to Italy and Spain, but not to Denmark, Finland and Norway. Sweden simply made the call to take measures that don’t destroy the free society."
Interesting line towards the end about expecting higher deaths (in the near future) than other locked down countries, but "still all within the confines of a bad winter flu". If that turns out to be true then Sweden will have made the right call (from an economics/deaths perspective - the libertarian perspective is a different issue for which 'right' depends on values more than numbers) but that's not something that we know yet. If fatality rate is 1% (it may turn out to be much lower, when we know more) then it will likely be a lot worse than bad winter flu, depending how many get infected.
Having been in Sweden extensively during my PhD in the two main cities, including for a continuous period of two months - and knowing a number of people there, although mostly among the urban professional classes - I do think the people there will be mostly listening to the advice and doing social distancing, without being compelled to do so. So they may do plenty of their own curve flattening without a full lockdown. From an epidemiological perspective, it will be fascinating to see. From a humanitarian perspective, I hope it will not be too distressing to see.
The government in Denmark is under a massive amount of pressure to do as Sweden has done - to the extent that our PM has worried all the senior medics by dangling the prospect of some unlocking in the week after Easter - if over the next week or so Sweden doesn't diverge massively from Denmark it might become impossible to maintain the Danish lockdown in its current form - which is already looser than the UK.
Not testing frontline HCPs who are symptomatic might be strategy and not due to capacity problems.
If 1 in 4 negative test results are actually wrong (these clinicians actually have Covid19) and the incorrect result means they then go into work with huge numbers of vulnerable patients, then that is very dangerous indeed.
Might be better for them to sit it out and self-isolate for 7 days to be sure.
Perhaps that's what PHE are doing but are reluctant to reveal for obvious reasons. Namely the reaction.. 'what!? the tests are actually wrong!?!!' from the usual idiot crowd.
I thought that the test where more lickly to give a false Positive, and 'relatively' unlikely to give a false negative, have I got that the wrong way around?
But overall I agree with your assessment, Lots of testing a month ago, would have allowed, South Korean Steal, 'test, track and test' and therefor keep infection down and no need for a lock down. but at this stage with 4,000 people a day being identified, how we would track that many people is probably not practical.
Other way round. If you think about the process involved there is a decent chance that the swabbing technique around the mouth and throat doesn't catch the virus - false negative. Moreover, Covid19 impacts more on the lower respiratory tract whereas swabbing grabs material from the upper respiratory tract.
On the other hand, there is a low chance of finding evidence of the virus without it actually being there - false positive. It's not like it's a normal biomarker that you always have in your body.
@Foxy suggested a false negative rate of circa 25% a while back. Not sure where he got this from.
The Oxford Centre for Evidence-Based Medicine did a literature review a few days ago and found that there was only poor quality evidence available re the accuracy of oropharyngeal versus nasopharyngeal swabs for COVID-19, and it was not possible to accurately assess or compare their sensitivity, nor figure out what the effect might be of combining the two methods... I can understand why PHE is working very hard on "getting testing right". Would be a nightmare for them to end up with building an entire testing infrastructure around a testing procedure that's worse than useless (as has been pointed out downthread, false negatives in the healthcare worker context are particularly dangerous).
Re false positives, there was a Chinese paper suggesting there were issues when people lived in the same space as someone who was infected - you might find RNA from viruses that got in the nose etc but hadn't actually caused an infection. This got a bit of an airing on PB but the paper was later withdrawn. https://pubmed.ncbi.nlm.nih.gov/32133832/
Latest figures log rate per million population. Italy definitely seems to be flattening off. Most countries still on an exponential line regardless of steps taken, but that's no surprise at all when you think about it (the deaths being recorded today were probably from infections around 7th-11th of March. Realistically, only Italy has had enough time since lockdowns for any real effect to be taken. (It would be good for journalists to point out the lag issue at some point)
We're still tracking extremely close to Italy + 15 days. Not sure exactly when our lockdown measures came into place vs theirs, though
It is interesting that Sweden's line is the same as other Countries
Thanks for producing this Andy_Cooke
I don't know how simple it would be, but, is there a way of indicating with a X when on that graph each nation implemented its Lock down?
I can have a crack. It looks rather busy and I'm not sure how easy it is to pick them out:
Shortly we will hear that armed police have deployed to kill the goat menace.
When wild boar escaped in Wiltshire, a good while ago, plod discovered that 9mm doesn't impress boar. More like mildly irritates. So they tried to borrow firearms from a local hunter. Who they had harassed about his hunting weapons non-stop for years....
I have vague recollections of stories in the local press about wild boar a few years ago. I expect people were surprised to discover they exist outside of Asterix comics.
They are very tasty to eat - hence the farming.
Ah yes - bit of an evolutionary double edged sword, being found tasty by humans.
My back of envelope R0 measure (new cases announced 31/3- 2/4 ÷ those announced 24-26/3) now at 2.31, down from 2.58 yesterday, and 3.25 at the beginning of this week.
On reporting date we're into post lockdown figures now, but on average a case reported on 24/3 will have onward infected most people before that date, and I'd be pretty sure onward infection time isn't as tightly distributed around 7 days as my measure allows for. I still expect my R0 to fall substantially in the next few days.
I suppose you mean R, seeing that R0 is the reproduction number in the absence of any interventions to reduce the spread.
But how anyone thinks they can calculate anything relating to the real spread of the virus from such wholly inadequate data - let alone daily changes (?!?) is beyond me.
Actually this is somewhere that people aren't totally consistent on terminology. Some people use R0 to mean "the reproduction number when there is no immunity from past exposures or vaccination, nor any deliberate intervention in disease transmission" (see eg this Australian government document which is worth a read for anyone who's interested in the modelling side - it's from a very accessible report entitled "Using Mathematical Models to Assess Responses to an Outbreak of an Emerged Viral Respiratory Disease").
What everyone is universally agreed on is that R0 only applies in a completely susceptible population. So if you reduce the proportion who are susceptible (whether by a vaccination campaign or by people who recover from the disease gaining immunity) then the net or effective reproduction number will be lower: R = s R0 where s is the proportion who are susceptible.
But if population A and population B have different age structures and/or different contact patterns, then the same disease will have a different R0 in the two populations. The thing that gets a bit dodgy is when population A and population B are really the same people, but behaving differently eg due to government intervention. Some people will say the R0 is the same but the R has changed due to the intervention. Other people will say it's the R0 that's changed, and reserve changes in R for when the proportion susceptible changes too - plenty of professional epidemiologists will maintain that distinction (the link goes to a recent LSHTM study who estimated the reduction of contacts in survey data would be sufficient to "reduce R0 from a value from 2.6 before the lockdown to 0.62 (0.37 - 0.89) during the lockdown", where clearly they view the intervention and subsequent behavioural change as altering R0 itself).
Whereas this Imperial study released the day before looks at death data to estimate how reproduction has changed over time, and focuses on Rt (time-varying effective reproduction number). Which is broadly what @Pro_Rata was trying to do but in a more statistically-informed way!
Please stop discussing matters in a scientific, intelligent manner. Your are raising the tone of the whole internet in an unacceptable manner. Please send some tweets in ALL CAPS immediately to make up for it,
Thanks all. Point taken on R0 Vs R, and I'm not claiming this is in any way perfect or statistically thorough, just a quick and dirty indicator of our progress in fighting the virus even as the absolute numbers continue to grow. In choosing how I measured this, I went for a 3 day rolling average to iron out bumps in the numbers of infections, I went for infections as a measure that lags the current situation less than if I went for deaths, and I go for 7 days to match the isolation period but also because you then compare the same days of week and iron out weekend effects. The Rt value may not b be perfect, but it will be indicative - <1 will be close to the major turning point, and as long as each nations methods are broadly internally consistent, Ft for a given t will be quickly comparable between nations.
If the govt went out and did 100k random tests tomorrow and 95% came back negative, wouldn't that be a waste of time/resources?
Given the 40%+ positive figures, it appears that testing is being done only on suspected cases. Which makes more sense to me.
I can't see the point in testing millions of people who've been stuck at home for a fortnight (NHS workers aside) knowing that when they emerge back outdoors they are going to get it anyway.
Surely the only positive thing a govt can do is play for time to help the NHS. They are resigned to the fact 80%+ of us will get the illness and are doing this lockdown to try to stagger it. Testing won't stop people getting it.
If those 100,000 tests were of key workers who are stuck in isolation because it is suspected they have the virus or a family member has it then yes I think it would be of very great value to have them done.
The Head of the English NHS Trusts was on the radio yesterday and said that they had been testing key workers who were stuck at home under 14 day quarantine and found that only 15% of them had the virus. That could make a big difference to workloads on the front line.
Thank you - yes, a good idea to test NHS staff (but even then they could catch the virus the next day). But is there any point doing testing on the likes of my mother in law, who hasn't seen daylight in 14 days'?
Not immediately. But if they can get the antibody tests going and find that a substantial proportion of the population has already had the virus then at that point testing people currently in isolation might mean at least some will be able to ease their restrictions - perhaps not going out as that would confuse matters and make policing it all more difficult but at least receive visitors and helpers without fear of contacting the disease.
Yeah agree 100% with that. The antibody test sounds like the one which will change the landscape dramatically.
I can't see a great deal of point in the standard virus test when you could test negative at 3pm and go out and contract the virus at 4pm!
A widely used and random antibody test might also reset the upper bound of how bad this can get on a population level and how far we are through this. If we can also antibody test a sample for other Coronas on a smaller scale, we might get lucky and find that nobody immune to Corona-A contracted COVID or, if they did, they were invariably asymptomatic. Such co-immunity is known between other Coronas, but that would also change the game drastically.
Can you provide a link for co-immunity for other coronaviruses?
I can't find where I originally read this - it was in one of the US explainers , and I recall it as cross-immunity between mild forms OC43 and 229E. However, the paper I've found today found no.link.
I suspect from the few results I can see, that the science here is not fully established and maybe I'm adding 2+2 a bit in thinking something is at play and here is a candidate something.
Not testing frontline HCPs who are symptomatic might be strategy and not due to capacity problems.
If 1 in 4 negative test results are actually wrong (these clinicians actually have Covid19) and the incorrect result means they then go into work with huge numbers of vulnerable patients, then that is very dangerous indeed.
Might be better for them to sit it out and self-isolate for 7 days to be sure.
Perhaps that's what PHE are doing but are reluctant to reveal for obvious reasons. Namely the reaction.. 'what!? the tests are actually wrong!?!!' from the usual idiot crowd.
I think that's why there around 7 people per 10 tests at the moment. Negative results may be double checked.
2 false negatives on same person a 9% chance.
This is only true if the two tests results on the one person are independent of each other.
Example: If fro almost all people a well swabbed throat has a 30% chance of not catching the virus then 30%x30%=9% is correct for the probability of 2 swabs not catching the virus.
But if the reason for 30% negative results is that some people happen to have very little virus in the throat and others a lot of virus in the throat then after testing negative for the first test, the probability that the same person gives a false negative again will be much higher than 30%.
Mr. kle4, an awful lot of animals in the world today are bred for their deliciousness.
On the other hand, the great tortoises were doomed.
That's why it's double edged - there's a chance we take extra care to keep them around due to being delicious. Or you're the Great Bustard (actually been reintroduced to Wiltshire now, but I doubt they will let us eat one).
@Andy_Cooke what is the Y-Axis on your chart? It says Log Deaths but the Y-Axis index goes up linearly not logarithmically or exponentially.
The logarithm (to base 10) of the deaths per million.
So: 0.5 is 3.16 (per million) 1.0 is 10 (per million) 1.5 is 31.6 (per million) 2.0 is 100 (per million) 2.5 is 316 (per million) 3.0 would be 1000 (per million)
Shortly we will hear that armed police have deployed to kill the goat menace.
When wild boar escaped in Wiltshire, a good while ago, plod discovered that 9mm doesn't impress boar. More like mildly irritates. So they tried to borrow firearms from a local hunter. Who they had harassed about his hunting weapons non-stop for years....
I have vague recollections of stories in the local press about wild boar a few years ago. I expect people were surprised to discover they exist outside of Asterix comics.
They are very tasty to eat - hence the farming.
Ah yes - bit of an evolutionary double edged sword, being found tasty by humans.
It has worked out really well for cows, sheep & pigs - they pretty much own the countryside in the UK.
Comments
If 1 in 4 negative test results are actually wrong (these clinicians actually have Covid19) and the incorrect result means they then go into work with huge numbers of vulnerable patients, then that is very dangerous indeed.
Might be better for them to sit it out and self-isolate for 7 days to be sure.
Perhaps that's what PHE are doing but are reluctant to reveal for obvious reasons. Namely the reaction.. 'what!? the tests are actually wrong!?!!' from the usual idiot crowd.
1) What is the accuracy of the current test?
2) What is the accuracy of diagnosis via symptoms?
It might actually be the case that diagnosis is better than the test....
Sadly I expect the obituary writers will be busy for quite some time...
I wonder - can people not see that kind of information would actually enable countries not so far along the curve to make sensible, evidence-based decisions, and might enable hundreds of thousands, if not millions of lives to be saved?
If we can also antibody test a sample for other Coronas on a smaller scale, we might get lucky and find that nobody immune to Corona-A contracted COVID or, if they did, they were invariably asymptomatic. Such co-immunity is known between other Coronas, but that would also change the game drastically.
It does still seem, even operating amongst communities in varying degrees of lockdown, that the upper bound of detected infections seen anywhere has been around 1%. It does feel like we either have asymptomatic cases and/or some prior immunity, else somewhere, some low level locality, would have blown this figure.
Then had a look at the amazing Orkney brewery's online shop. Their Dark Isle is the shizzle and as I can't get to a Tesco in Scotland at the moment I'll have a look at getting them to deliver. Its nearly double the Tesco price.
So a trip to Tesco to buy non-Scottish ale it will have to be.
I wonder if Dec 13th was Peak Boris? It's starting to look that way. Not sure though. He's a hard one to work out.
More chance of me becoming the pope than there is of me giving up the drink.
I don't know how simple it would be, but, is there a way of indicating with a X when on that graph each nation implemented its Lock down?
Complex stuff figuring out how to allocate these resources. Politicians and political pundits are probably not well placed in understanding the necessary subtlety.
These Catholic bears sound interesting though...
However, the utility function in my view is weighted more towards avoiding false negatives rather than false-positives. When hospitals are running with 1/3 of the staff then that equation might shift the other way.
Dec 13th is a good bet for peak Boris, if one assumes a rallying effect now is limited and he'll struggle to do the things he had otherwise planned.
But overall I agree with your assessment, Lots of testing a month ago, would have allowed, South Korean Steal, 'test, track and test' and therefor keep infection down and no need for a lock down. but at this stage with 4,000 people a day being identified, how we would track that many people is probably not practical.
Also if NHS staff are isolating unnecessarily (in that they don't have COVID-19) but may have another virus with similar symptoms instead then its presumably still a good idea for them to isolate.
Probably not a good idea to bring them back in to work to pass the alternative virus around even if it isn't COVID-19 causing other people to develop symptoms.
https://actualite.cd/2020/04/01/rdc-coronavirus-123-cas-confirmes-dont-11-deces
What everyone is universally agreed on is that R0 only applies in a completely susceptible population. So if you reduce the proportion who are susceptible (whether by a vaccination campaign or by people who recover from the disease gaining immunity) then the net or effective reproduction number will be lower: R = s R0 where s is the proportion who are susceptible.
But if population A and population B have different age structures and/or different contact patterns, then the same disease will have a different R0 in the two populations. The thing that gets a bit dodgy is when population A and population B are really the same people, but behaving differently eg due to government intervention. Some people will say the R0 is the same but the R has changed due to the intervention. Other people will say it's the R0 that's changed, and reserve changes in R for when the proportion susceptible changes too - plenty of professional epidemiologists will maintain that distinction (the link goes to a recent LSHTM study who estimated the reduction of contacts in survey data would be sufficient to "reduce R0 from a value from 2.6 before the lockdown to 0.62 (0.37 - 0.89) during the lockdown", where clearly they view the intervention and subsequent behavioural change as altering R0 itself).
So the false positive problem is miniscule - but the chances of a false negative are much higher.
There is already a lot of learning going on....Italy was unlucky with Lombardy..it sat on the first European hotspot and made unfortunate mistakes not knowing any better....
On the other hand we have made huge mistakes knowing what happened in Lombardy...lack of testing, delaying social distancing, failure to get PPE to the right spots....and if we get to 1000 a day fatalities images like running crowded tubes, Cheltenham and the Stereophonics concerts will come back to haunt us...
https://www.spectator.co.uk/article/no-lockdown-please-w-re-swedish
https://twitter.com/foxinsoxuk/status/1245484390525874184?s=19
On the other hand, there is a low chance of finding evidence of the virus without it actually being there - false positive. It's not like it's a normal biomarker that you always have in your body.
I would give some blame to those who went along, although the Government should've been stricter and banned it. Government action or inaction doesn't wholly absolve individuals of personal responsibility.
Pesumably a sign of how close to the wire the NHS is working that they would rather have folk back doing something, rather than not have them on the ward at all.
https://twitter.com/aliceolilly/status/1245729876105211905?s=20
From the article:
"This Swedish exceptionalism is about principle, not epidemiology. It’s true that we’re perhaps less at risk due to our high rate of single-person households and low number of smokers. Closing the schools would, as well, have a bigger impact in a country where almost all mums are working mums. But frankly, all these explanations miss the point: yes, they make us different to Italy and Spain, but not to Denmark, Finland and Norway. Sweden simply made the call to take measures that don’t destroy the free society."
One does wonder about the intersection of the sets of those who report their crimes to the police and those holding parties at the moment.
Probably includes baseball bat wielding kimono wearing Remaniacs, as well....
This is an example of a more hopeful paper relating SARs to existing CoVs:
https://academic.oup.com/jid/article/191/12/2033/839720
I suspect from the few results I can see, that the science here is not fully established and maybe I'm adding 2+2 a bit in thinking something is at play and here is a candidate something.
So the left`s pressure to lockdown, with the costs that that was bound to entail, will transform into a new Labour Party narrative that getting county`s finances in the direction of sanity post-virus will amount to Tory Austerity Mark2.
Words fail me.
When wild boar escaped in Wiltshire, a good while ago, plod discovered that 9mm doesn't impress boar. More like mildly irritates. So they tried to borrow firearms from a local hunter. Who they had harassed about his hunting weapons non-stop for years....
The Oxford Centre for Evidence-Based Medicine did a literature review a few days ago and found that there was only poor quality evidence available re the accuracy of oropharyngeal versus nasopharyngeal swabs for COVID-19, and it was not possible to accurately assess or compare their sensitivity, nor figure out what the effect might be of combining the two methods... I can understand why PHE is working very hard on "getting testing right". Would be a nightmare for them to end up with building an entire testing infrastructure around a testing procedure that's worse than useless (as has been pointed out downthread, false negatives in the healthcare worker context are particularly dangerous).
Re false positives, there was a Chinese paper suggesting there were issues when people lived in the same space as someone who was infected - you might find RNA from viruses that got in the nose etc but hadn't actually caused an infection. This got a bit of an airing on PB but the paper was later withdrawn.
https://pubmed.ncbi.nlm.nih.gov/32133832/
The seagulls are more of an issue
Fortunately another armed plod arrived about 30 seconds later and told him to stop being a twat.
https://twitter.com/chriscurtis94/status/1245704235515351042
Having been in Sweden extensively during my PhD in the two main cities, including for a continuous period of two months - and knowing a number of people there, although mostly among the urban professional classes - I do think the people there will be mostly listening to the advice and doing social distancing, without being compelled to do so. So they may do plenty of their own curve flattening without a full lockdown. From an epidemiological perspective, it will be fascinating to see. From a humanitarian perspective, I hope it will not be too distressing to see.
Looking at table 2, we see that out of 50 patients admitted to ICU (representing 26% of all inpatients so perhaps not far different to the situation chez Foxy) there were only 11 survivors (22%) compared to 39 deaths (78%). All three who received ECMO died; 31 out of the 32 who received invasive mechanical ventilation died; 24 out of the 26 who received non-invasive mechanical ventilation died; 33 of the 41 who received high-flow nasal cannula oxygen therapy died. The median ICU stay was 8 days (IQR from 4 to 12) for those who died and 7 days (IQR from 2 to 9) for those who survived.
Fingers crossed British ICUs don't end up like this. NHS Nightingale sounds like it is going to be brutal work:
Volunteers working at the NHS Nightingale coronavirus hospital have been told to prepare for the fact that up to 80 per cent of patients who are on ventilators will die, MailOnline can reveal.
Selfless heroes flocking to staff the emergency 4,000-bed unit in east London have been told to 'be prepared to see death', with a mortality rate of 50 to 80 per cent among those on ventilators.
Are there any reasons to be more optimistic than those Wuhan stats suggest? If the Mail report is accurate (and whenever you write a sentence that starts like that about a medical story, you know the "if" deserves red flashing fairy lights around it, but this one sounds plausible) then it doesn't sound like the top brass are very hopeful.
Their personalities are a bit like that bloke from the pub that everyone gives a wide birth to. Normally fine, but can be a bit of nutter when they get upset with something.
Hence they escape due to shear persistency in attacking things like fences.
Stopping them requires a cannon - a big game rifle....
Analytical sensitivity and efficiency comparisons of SARS-COV-2 qRT-PCR assays
https://www.medrxiv.org/content/10.1101/2020.03.30.20048108v1.article-metrics
Though of course that says nothing about the consistency and accuracy of individual swab sampling.
The Rt value may not b be perfect, but it will be indicative - <1 will be close to the major turning point, and as long as each nations methods are broadly internally consistent, Ft for a given t will be quickly comparable between nations.
On the other hand, the great tortoises were doomed.
https://www.medrxiv.org/content/10.1101/2020.03.18.20037101v1.full.pdf
Example: If fro almost all people a well swabbed throat has a 30% chance of not catching the virus then 30%x30%=9% is correct for the probability of 2 swabs not catching the virus.
But if the reason for 30% negative results is that some people happen to have very little virus in the throat and others a lot of virus in the throat then after testing negative for the first test, the probability that the same person gives a false negative again will be much higher than 30%.
So:
0.5 is 3.16 (per million)
1.0 is 10 (per million)
1.5 is 31.6 (per million)
2.0 is 100 (per million)
2.5 is 316 (per million)
3.0 would be 1000 (per million)