Can't find where I saw it now, but saw recently a good explanation of how pre-existing herd immunity (e.g. vaccinated population) works a bit differently to how herd immunity develops naturally, where the fraction that are immune is not constant over time. The upshot is more people become infected by the disease being spread - e.g. you might stop the virus spreading if (say) 60% are pre-immune, but in a naive population, 75% might catch it before the HI stops it. Importantly, the higher the R number, the bigger this overshoot will be, so slowing the spread of the virus also decreases the endpoint in the total number who'll actually catch it.
Some people claiming that this supports theory of HIT of 40%, but not sure how...
This seems pretty mainstream to me :
"... In June, one month following the epidemic peak, 44% of the population was seropositive for SARS-CoV-2, equating to a cumulative incidence of 52%, after correcting for the false-negative rate of the antibody test. The seroprevalence fell in July and August due to antibody waning. After correcting for this, we estimate a final epidemic size of 66%...
i thought people estimated 70%
Re: Seasonal effect?
Posted: Tue Sep 22, 2020 12:30 pm
by badger
Of course, yes. Thanks PeteB, very interesting (re London wriggle)
(and re above 40% HIT, I just realised that would be calculated from an R number of 2.5)
Am not sure how their call for "more targeted measures" would actually work, maybe move all the over 65s to the isle of man so the rest of us can carry on as normal?
This feels as good a moment as any to point out that "shielding" the vulnerable is, in reality, isolating us and cutting us off from the support we need for other issues.
Am not sure how their call for "more targeted measures" would actually work, maybe move all the over 65s to the isle of man so the rest of us can carry on as normal?
This feels as good a moment as any to point out that "shielding" the vulnerable is, in reality, isolating us and cutting us off from the support we need for other issues.
I thought that was what I was pointing out? Also that it works the other way: old and vulnerable may well be providing valuable function and key role eg in their work, childcare, support networks etc. Shielding them 'til it blows over' is good for neither "side". We're talking, what, 20 million people here? They're not just sat around on their arse.
Am not sure how their call for "more targeted measures" would actually work, maybe move all the over 65s to the isle of man so the rest of us can carry on as normal?
This feels as good a moment as any to point out that "shielding" the vulnerable is, in reality, isolating us and cutting us off from the support we need for other issues.
I thought that was what I was pointing out? Also that it works the other way: old and vulnerable may well be providing valuable function and key role eg in their work, childcare, support networks etc. Shielding them 'til it blows over' is good for neither "side". We're talking, what, 20 million people here? They're not just sat around on their arse.
I wasn't disagreeing, more using your post as a springboard to expand on the point. Also, completely agreed on the second point re: valuable function.
Some shielders are elderly, some are like me, and disabled. Others live very normal working age lives, for example, one of my neighbours and her uni age daughter both have a heriditary lung condition, but are otherwise in good health.
This feels as good a moment as any to point out that "shielding" the vulnerable is, in reality, isolating us and cutting us off from the support we need for other issues.
I thought that was what I was pointing out? Also that it works the other way: old and vulnerable may well be providing valuable function and key role eg in their work, childcare, support networks etc. Shielding them 'til it blows over' is good for neither "side". We're talking, what, 20 million people here? They're not just sat around on their arse.
I wasn't disagreeing, more using your post as a springboard to expand on the point. Also, completely agreed on the second point re: valuable function.
Some shielders are elderly, some are like me, and disabled. Others live very normal working age lives, for example, one of my neighbours and her uni age daughter both have a heriditary lung condition, but are otherwise in good health.
Indeed. Also, am assuming some don't know they're vulnerable until they get it, and it reveals said vulnerability...eg latent heart condition.
Some shielders are elderly, some are like me, and disabled. Others live very normal working age lives, for example, one of my neighbours and her uni age daughter both have a heriditary lung condition, but are otherwise in good health.
Indeed. Also, am assuming some don't know they're vulnerable until they get it, and it reveals said vulnerability...eg latent heart condition.
[/quote]
Yeah, there was a footballer in his early twenties in Spain who died from it who turned out to have undiagnosed (but probably treatable) leukemia, during the first wave in Spain.
Some shielders are elderly, some are like me, and disabled. Others live very normal working age lives, for example, one of my neighbours and her uni age daughter both have a heriditary lung condition, but are otherwise in good health.
Indeed. Also, am assuming some don't know they're vulnerable until they get it, and it reveals said vulnerability...eg latent heart condition.
Yeah, there was a footballer in his early twenties in Spain who died from it who turned out to have undiagnosed (but probably treatable) leukemia, during the first wave in Spain.
Of course, yes. Thanks PeteB, very interesting (re London wriggle)
(and re above 40% HIT, I just realised that would be calculated from an R number of 2.5)
Are you sure? I reckon 2.5 would give you 60%.
Fine, Eames, Heymann: "the simple herd immunity threshold for random vaccination of Vc = (1−1/R0), using the symbol Vc for the critical minimum proportion to be vaccinated (assuming 100% vaccine effectiveness)" https://academic.oup.com/cid/article/52/7/911/299077
Of course, yes. Thanks PeteB, very interesting (re London wriggle)
(and re above 40% HIT, I just realised that would be calculated from an R number of 2.5)
Are you sure? I reckon 2.5 would give you 60%.
Fine, Eames, Heymann: "the simple herd immunity threshold for random vaccination of Vc = (1−1/R0), using the symbol Vc for the critical minimum proportion to be vaccinated (assuming 100% vaccine effectiveness)" https://academic.oup.com/cid/article/52/7/911/299077
(1-1/2.5) gives me 0.6
I'm sure ....it's wrong.
Minor brain melt yesterday.
Okay, major brain melt.
1.7?
Re: Seasonal effect?
Posted: Wed Sep 23, 2020 8:01 am
by PeteB
Yep - either way
Reffective = R0x (x = proportion that are susceptible, so if 40% infected 60% susceptible)
Reffective = 1.7 * 0.6 = 1.02 - so very slightly above 1
or (1-1/1.7) = 0.41
Re: Seasonal effect?
Posted: Wed Sep 23, 2020 8:33 am
by PeteB
(but doesn't take into account loss of immunity / reinfections ! )
Professor Carl Heneghan, director of Oxford University's Centre for Evidence-Based Medicine, believes the UK is moving towards the Swedish approach to dealing with COVID-19.
Sweden, which so far has decided against lockdowns as a means to contain COVID-19, is seeing early signs that the number of coronavirus cases are rising again and could impose new measures in the capital, its chief health officials said on Tuesday.
Re: Seasonal effect?
Posted: Sun Oct 11, 2020 2:36 pm
by snoozeofreason
Heneghan is at it again this time telling Spectator readers (paywalled but you can get a limited ration for free) that
Evidence from Italy casts new light on this. ISTAT, Italy’s national statistics institute, and Istituto Superiore di Sanità (ISS), an Italian health authority, published a report on the impact of Covid-19 deaths recorded up to the 16 July. They found 28 per cent of death certificates they studied have Covid-19 as the only cause of death. The remainder, over two thirds, are deaths with Covid: i.e. people with preexisting conditions such as hypertension, diabetes, heart disease and cancer. Often with more than one condition in the same person. So the figure for ‘Covid deaths’ in this instance will be almost four times as big as the number who died from Covid.
[My bolding]
I am not a professor of evidence-based medicine, but I am not sure that the conclusion of that argument follows from its premise (and I have a vague recollection that the More or Less program came to the same conclusion when similar statistics were aired some time earlier). I suffer from hypertension, so by Heneghan's argument I can't die from Covid. In fact I can't die of anything that's not related to my hypertension.
Heneghan is at it again this time telling Spectator readers (paywalled but you can get a limited ration for free) that
Evidence from Italy casts new light on this. ISTAT, Italy’s national statistics institute, and Istituto Superiore di Sanità (ISS), an Italian health authority, published a report on the impact of Covid-19 deaths recorded up to the 16 July. They found 28 per cent of death certificates they studied have Covid-19 as the only cause of death. The remainder, over two thirds, are deaths with Covid: i.e. people with preexisting conditions such as hypertension, diabetes, heart disease and cancer. Often with more than one condition in the same person. So the figure for ‘Covid deaths’ in this instance will be almost four times as big as the number who died from Covid.
[My bolding]
I am not a professor of evidence-based medicine, but I am not sure that the conclusion of that argument follows from its premise (and I have a vague recollection that the More or Less program came to the same conclusion when similar statistics were aired some time earlier). I suffer from hypertension, so by Heneghan's argument I can't die from Covid. In fact I can't die of anything that's not related to my hypertension.
While the official number of covid deaths in the UK is 42760,* even https://coronavirus.data.gov.uk/ now also gives the number of death certificates on which covid was mentioned, which is currently 57347.
(* - based on dying within 28 days of a positive test but you can still see the join where that rule was implemented.)
So if you were going to try to estimate deaths due to "just covid" you should at least start with the higher number.
But the issue with Italy, especially the north of Italy at the beginning of the pandemic, was the way in which the virus managed to get into care homes and hospitals where of course it's going to do a lot of damage to people who have underlying conditions.
The question is whether you think this means we need to lock down more to protect the vulnerable, or f.ck it they're going to die soon anyway. But it's clear from the UK stats that the excess deaths represent people dying years earlier than they otherwise would have.
The question is whether you think this means we need to lock down more to protect the vulnerable, or f.ck it they're going to die soon anyway. But it's clear from the UK stats that the excess deaths represent people dying years earlier than they otherwise would have.
Pop quiz: What's the life expectancy of the average 80-year-old in the UK? Spoiler:
I am not a professor of evidence-based medicine, but I am not sure that the conclusion of that argument follows from its premise (and I have a vague recollection that the More or Less program came to the same conclusion when similar statistics were aired some time earlier). I suffer from hypertension, so by Heneghan's argument I can't die from Covid. In fact I can't die of anything that's not related to my hypertension.
He's going to tie himself up in knots here.
He's recently been banging on about how we shouldn't shut pubs and restaurants - become some cases of COVID (a small minority) are picked up in hospital as Health care-associated infections (HCAIs).
But according to Heneghan's logic - if you were perhaps visiting hospital because of "hypertension, diabetes, heart disease or cancer" and pick up COVID while you're there - then die, you shouldn't be counted in the COVID death numbers at all. According to Heneghan's definition - that's a death WITH COVID rather than a death FROM COVID.
Consequently, according to Heneghan's definitions - HCAIs cannot contribute to the COVID deaths numbers - so we should be shutting down the sources of community infection (pubs and restaurants)!!
Wonder what "Komedy Karl" (as some people are calling him on Twitter) would make of this???
He's recently been banging on about how we shouldn't shut pubs and restaurants - become some cases of COVID (a small minority) are picked up in hospital as Health care-associated infections (HCAIs).
He also seems to assume that any patient whose first positive test occurs more than seven days after admission must have acquired the virus in hospital. If patients were tested every day, and there were no false negatives, then that might be sound. But I'm not sure that it works like that.
Re: Seasonal effect?
Posted: Mon Oct 12, 2020 11:52 am
by badger
Sorry if covered elsewhere, but it seems he's been funded by the Govt (I think Whitty at DHSC sits atop the tree with NIHR on it?) especially for this service,,,
Will make for an interesting funding review, if there ever is one. Top marks for impact, I guess.
NIHR School of Primary Care – supports Carl Heneghan
In response to the current pandemic, the CEBM set up the Oxford COVID-19 Evidence Service. This service includes international collaborations from countries such as Italy where the outbreak has been particularly hard. Together we review and summarise the evidence and data to understand and support policy to tackle the current pandemic. The service has garnered considerable impact locally, nationally and internationally.
Our current funding priorities are
Theme 1: Synthesise high-quality, patient-focused COVID-19 evidence that benefits the public, clinicians and decision-makers.
Theme 2: Promote and disseminate our evidence-based findings through our existing international networks, as well as through more extensive networks, social and mainstream media.
Theme 3: Provide in-depth analysis on the initial transmission dynamics, the responses by individual countries, and the impact on causes of deaths.
Theme 4: Undertake an in-depth analysis of the cause of death across Europe with a special focus on Italy and the UK.
Theme 5: Understand the impact of densities on future healthcare, the potential role of urban concentrations and their relationship to rural surrounds to prevent, but also alarmingly to promote, communicable diseases across local and global scales.
Theme 6: Identify ways in which society can recover in a post-pandemic climate, including how social capital can be mobilised, the role of social prescribing and through the enhanced use of digital technologies.
Theme 7: Develop a greater understanding of how the cultural, arts and humanities sectors (e.g. green spaces, libraries and museums) can support society through improved physical and mental well-being immediately following a pandemic and in the future.
Theme 8: provide evidence-based solutions to mitigate the need for suppression strategies in the future (suppression means the closing down of schools, the economy and society).
Re: Seasonal effect?
Posted: Mon Oct 12, 2020 12:38 pm
by OneOffDave
Taking a look at 'early harvest' - the deaths of those people with underlying health conditions who die with Covid, the big unanswered question when saying "That's alright then, they were going to die anyway" is how much sooner they've died.
Taking a look at 'early harvest' - the deaths of those people with underlying health conditions who die with Covid, the big unanswered question when saying "That's alright then, they were going to die anyway" is how much sooner they've died.
Various estimates I've seen have put the average number of years of life lost (YLL) to COVID per death at around 10 years.
And study repports > 10 YLL in the UK... "Deaths from COVID-19 represent a substantial burden in terms of per-person YLL, more than a decade, even after adjusting for the typical number and type of LTCs found in people dying of COVID-19." https://wellcomeopenresearch.org/articles/5-75
Taking a look at 'early harvest' - the deaths of those people with underlying health conditions who die with Covid, the big unanswered question when saying "That's alright then, they were going to die anyway" is how much sooner they've died.
Various estimates I've seen have put the average number of years of life lost (YLL) to COVID per death at around 10 years.
And study repports > 10 YLL in the UK... "Deaths from COVID-19 represent a substantial burden in terms of per-person YLL, more than a decade, even after adjusting for the typical number and type of LTCs found in people dying of COVID-19." https://wellcomeopenresearch.org/articles/5-75
Yes, it's not the 6 months or so that a lot of people seem to be implying with their "it's only the old and vulnerable" approach
Re: Seasonal effect?
Posted: Tue Oct 13, 2020 3:58 pm
by PeteB
Yes, I think Carl Heneghan, the Centre for Evidence Based Medicine and Sunetra Gupta have been very effective at undermining the more mainstream / SAGE advice. They were invited to give evidence and Tory MPS and ministers(Alok Sharma) have alluded to the fact that there are differing scientific opinions
The interview on radio 4 with Charles Walker recited all the lockdown sceptic points and name checked Heneghan and the Centre for Evidence Based Medicine
We can knock him, I suppose, but Heneghan has helped me arrive at a more relaxed attitude to road safety. I used to worry about being run over by a bus, but my comorbidities mean I would just be dying with a bus on top of me. Knowing that helps me put things in perspective.
