Trinucleus wrote: Mon Dec 13, 2021 10:56 pm
While we're asking questions...
If Omicron is more contagious, do we know if 2m social distancing is still safe? Is the safe time for close contact shorter?
It's not still safe and it never was. The 2m thing was based on an incorrect theory for how it was transmitted. It was initially believed that transmission was by droplets breathed out which fell under gravity, so you could work out a safe distance based on how far the droplets would travel. Unfortunately, transmission is actually by aerosols - much finer particles which can float in the air for a long time, so distance from an infected person is only a small part of it - what is much more important is air circulation. This is why there was no noticable transmission as a result of outdoor protests and similar gatherings, yet lots of transmission in enclosed spaces with poor ventilation.
Imagine the infectious person as if they were a smoker with the smoke representing the infectious material. If they're standing near you, you may get a face full of concentrated smoke, so you're infected. But if they're in a room they may fill it with smoke, so you get strong exposure anywhere.
It seems quite plausible that the time to get infected is shorter, but it is also possible that it isn't and the difference is solely in ability to infect people at the same dose. I have seen no data that sheds any light on this point.
raven wrote: Tue Dec 14, 2021 5:45 pm
Is faster doubling just down to higher transmission (1 person infecting more people) or is it that plus slightly shorter incubation?
Well, notice that by making people self-test and self-isolate we are putting strong selection pressure on the virus to be infectious earlier so that people test negative due to low viral load but it increases fast enough that they infect others before they next take a test. So I would expect that eventually we would see a variant which spreads as fast as possible. Omicron may not be that variant, but it seems very likely that it is at least a step in that direction.
Trinucleus wrote: Mon Dec 13, 2021 10:56 pm
While we're asking questions...
If Omicron is more contagious, do we know if 2m social distancing is still safe? Is the safe time for close contact shorter?
It's not still safe and it never was. The 2m thing was based on an incorrect theory for how it was transmitted. It was initially believed that transmission was by droplets breathed out which fell under gravity, so you could work out a safe distance based on how far the droplets would travel. Unfortunately, transmission is actually by aerosols - much finer particles which can float in the air for a long time, so distance from an infected person is only a small part of it - what is much more important is air circulation. This is why there was no noticable transmission as a result of outdoor protests and similar gatherings, yet lots of transmission in enclosed spaces with poor ventilation.
Imagine the infectious person as if they were a smoker with the smoke representing the infectious material. If they're standing near you, you may get a face full of concentrated smoke, so you're infected. But if they're in a room they may fill it with smoke, so you get strong exposure anywhere.
It seems quite plausible that the time to get infected is shorter, but it is also possible that it isn't and the difference is solely in ability to infect people at the same dose. I have seen no data that sheds any light on this point.
To a certain extent. People can still be infected via droplets, but as you write, aerosol transmission is a much more important means.
I think that meter distancing rules are still a good idea as at the population level they'll probably reduce the number of people who can fit into rooms at once, and so decrease the numbers involved in superspreader events.
A study led by researchers from the LKS Faculty of Medicine at The University of Hong Kong (HKUMed) provides the first information on how the novel Variant of Concern (VOC) of SARS-CoV-2, the Omicron SARS-CoV-2 infect human respiratory tract. The researchers found that Omicron SARS-CoV-2 infects and multiplies 70 times faster than the Delta variant and original SARS-CoV-2 in human bronchus, which may explain why Omicron may transmit faster between humans than previous variants. Their study also showed that the Omicron infection in the lung is significantly lower than the original SARS-CoV-2, which may be an indicator of lower disease severity. This research is currently under peer review for publication.
lpm wrote: Thu Dec 09, 2021 8:30 pm
Obviously venues have to close. We need to embrace lockdownism again.
Voluntary action is hurting the nightclubs etc already, though. There will be a lot of empty seats at panto and a lot of cancelled Christmas parties. Voluntary action works quite well.
Yes
Mandatory action also protects the venues better against loss of earnings.
This graph is scary, 4.4% to 23.4% between 6th December and 11th December
However, there are several things that we do know. For instance, coronaviruses are seasonal in the northern hemisphere. As winter arrives, it therefore shouldn’t be that surprising that ‘about 1,000 daily respiratory admissions occur at this time of year in England’.
Yeah - that'll explain the 800-900 admitted each day due to Delta in July and August (notice he specifically say "coronaviruses" are seasonal - then uses data on what are usually influenza and bacterial pneumonia admissions to back up his claim).
He'll probably delete it soon - so here are the words...
Dec 11th
Carl 'no signs of a second wave' Heneghan wrote:PCR Positivity in England has hardly changed in a month (9.7%) - any change in case counts is noise from variation in testing numbers
Trinucleus wrote: Mon Dec 13, 2021 10:56 pm
While we're asking questions...
If Omicron is more contagious, do we know if 2m social distancing is still safe? Is the safe time for close contact shorter?
It's not still safe and it never was. The 2m thing was based on an incorrect theory for how it was transmitted. It was initially believed that transmission was by droplets breathed out which fell under gravity, so you could work out a safe distance based on how far the droplets would travel. Unfortunately, transmission is actually by aerosols - much finer particles which can float in the air for a long time, so distance from an infected person is only a small part of it - what is much more important is air circulation. This is why there was no noticable transmission as a result of outdoor protests and similar gatherings, yet lots of transmission in enclosed spaces with poor ventilation.
Imagine the infectious person as if they were a smoker with the smoke representing the infectious material. If they're standing near you, you may get a face full of concentrated smoke, so you're infected. But if they're in a room they may fill it with smoke, so you get strong exposure anywhere.
It seems quite plausible that the time to get infected is shorter, but it is also possible that it isn't and the difference is solely in ability to infect people at the same dose. I have seen no data that sheds any light on this point.
To a certain extent. People can still be infected via droplets, but as you write, aerosol transmission is a much more important means.
I think that meter distancing rules are still a good idea as at the population level they'll probably reduce the number of people who can fit into rooms at once, and so decrease the numbers involved in superspreader events.
Thanks. That explains the current campaign about opening windows
However, there are several things that we do know. For instance, coronaviruses are seasonal in the northern hemisphere. As winter arrives, it therefore shouldn’t be that surprising that ‘about 1,000 daily respiratory admissions occur at this time of year in England’.
Yeah - that'll explain the 800-900 admitted each day due to Delta in July and August (notice he specifically say "coronaviruses" are seasonal - then uses data on what are usually influenza and bacterial pneumonia admissions to back up his claim).
This whole pandemic thing has multiple causal factors. It is misleading to pick out one and concentrate on it. I think coronaviruses -in general- are seasonal. Sars-cov-2 is a novel corona virus. Being new means there was no community immunity so it could spread very easily at any time of year.
Each significant new mutation is novel and reduces the effect of acquired immunity. Now we have the rather interesting situation of a significantly evolved variant, able to escape immunity to some extent, whether community or vaccination derived. At the same time it is emerging during the Northern hemisphere winter, at Christmas, when people gather indoors in large groups. Talk about a perfect storm.
Any article authored by Heneghan and Jefferson should be ignored.
Masking forever
Putin is a monster.
Russian socialism will rise again
He'll probably delete it soon - so here are the words...
Dec 11th
Carl 'no signs of a second wave' Heneghan wrote:PCR Positivity in England has hardly changed in a month (9.7%) - any change in case counts is noise from variation in testing numbers
meanwhile in reality:
I guess the rise in S gene dropout in London to over 51% in 2 weeks is just due to testing too
If the Omicron is localised, isn't that what you'd expect? Delta is carrying on doing its thing of not going down, but Omicron is increasing in hotspots within the area of interest. It'll only take over when it spreads from the hotspots to the notspots.
(Not suggesting this is the case, just thinking out loud).
If the Omicron is localised, isn't that what you'd expect? Delta is carrying on doing its thing of not going down, but Omicron is increasing in hotspots within the area of interest. It'll only take over when it spreads from the hotspots to the notspots.
(Not suggesting this is the case, just thinking out loud).
I think it's more simple - Delta will respond to the lockdown measures in the normal way. Was R=1.1, add in masks and WFH and voluntary action and it will be definitely R<1. And probably drop to R=0.7 or lower. Halving every week or two. So it will fade away.
Whoever's doing those charts needs to swap them around - always put the constant (Delta in this case) down the bottom, put the exponential on top.
Italy reported more than 23,000 today, which is the highest number since the 1st of April. We had an end-of-winter rebound with a couple of days in mid March reporting above 26,000; we were coming down off that in April.
having that swing is a necessary but not sufficient condition for it meaning a thing
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If the Omicron is localised, isn't that what you'd expect? Delta is carrying on doing its thing of not going down, but Omicron is increasing in hotspots within the area of interest. It'll only take over when it spreads from the hotspots to the notspots.
(Not suggesting this is the case, just thinking out loud).
I think it's more simple - Delta will respond to the lockdown measures in the normal way. Was R=1.1, add in masks and WFH and voluntary action and it will be definitely R<1. And probably drop to R=0.7 or lower. Halving every week or two. So it will fade away.
Whoever's doing those charts needs to swap them around - always put the constant (Delta in this case) down the bottom, put the exponential on top.
As I said, I was just thinking out loud, I know nothing. Just thought that a possible explanation that Omi doesn't seem to be replacing delta in that graph may be that they're spreading in two different populations. First thought was geographic things, but it could be something else - different age groups (e.g. Delta might be popular with the kids, but Omi with boring middle aged people), or whatever. Even if my thoughts are right, I doubt Omi will stick to whatever its doing for very long, so its probably a bit pointless to speculate.
(I don't like that style of graph, especially when there's only two categories. Two lines would be easier to compare the absolute numbers and the percentage can be plotted separately, like they did.)
Well that's my last social event of the year over.
Having already cancelled a trip to uni to see my PhD supervisor for the first time in over 2 years, I'd kept an agreement to meet a couple of friends an hour away.
On the way there only one train was cancelled due to staff shortages. Luckily I checked at 830 and found they'd cancelled every train service after 9, and all the buses, so I legged it and will hopefully make it home tonight.
That's it for a few months, eh? Locked in my mum's flat till I can get home to Portugal.
Turns out running hot and hoarding vaccines was dumb, who knew (except literally everyone who knows anything).
We have the right to a clean, healthy, sustainable environment.
Challenges in inferring intrinsic severity of SARS-CoV-2 Omicron variant from early population-level impact
Inferring the severity of an emerging infectious agent presents specific challenges due to the inevitably imperfect state of data early in an epidemic. Here we specifically consider the additional impact of existing population immunity on estimates of intrinsic virulence, using the example of early evidence of the Omicron variant of SARS-CoV-2 emerging in South Africa. Without accounting for vaccination rates and prior infections, among other factors, the true risk of severe infection will be systematically underestimated. At the time of writing it is premature to consider Omicron infections to be intrinsically milder that those caused by preceding variants.
raven wrote: Tue Dec 14, 2021 5:45 pm
Is faster doubling just down to higher transmission (1 person infecting more people) or is it that plus slightly shorter incubation?
Well, notice that by making people self-test and self-isolate we are putting strong selection pressure on the virus to be infectious earlier so that people test negative due to low viral load but it increases fast enough that they infect others before they next take a test. So I would expect that eventually we would see a variant which spreads as fast as possible. Omicron may not be that variant, but it seems very likely that it is at least a step in that direction.
Further to that, I remembered I bookmarked this excellent Epidemic Calculator ages ago. Playing with the sliders on that, I don't think incubation period has much effect on doubling times. But R0 definitely does.
