advertisement


Coronavirus - the new strain XVIII

Status
Not open for further replies.
That was the first national breakdown of deaths from Delta under the criteria for reporting that have been used throughout most of the pandemic - the numbers are still small but are statistically relevant.

"the 28-day case fatality rate for Delta remains low (0.1%), though mortality is a lagged indicator and the vast majority of cases are still within the 28 days of follow-up required." [see below]

Here's more on the PHE technical briefing this morning - the risk assessment for Delta has been updated too.

Now Public Health England (PHE) has revealed that up to 96% of new Covid cases in the UK involve the Delta variant, and that it has about a 60% increased risk of household transmission compared with the Alpha variant.

https://www.theguardian.com/world/2021/jun/11/delta-variant-is-linked-to-90-of-covid-cases-in-uk
 
Of course. That's why I'm not using those stats to try and make a point.

That is precisely what you are trying to do, of course. The poor folks probably got run over by a car, had asthma at the same time with a touch of aids for good measure - the thing is I've heard it all before and it's just how the early deaths were explained away last March and again in September.
 
Here's an update on deaths from Delta from PHE

There have been 42 deaths in England of people who were confirmed as having the Delta variant of Covid-19 and who died within 28 days of a positive test. Of this number, 23 were unvaccinated, seven were more than 21 days after their first dose of vaccine, and 12 were more than 14 days after their second dose. I.e. Nearly 30% of these had received two doses

https://www.theguardian.com/world/l...08971c08d9a7a8#block-60c331258f08971c08d9a7a8
For contrast, in May in UK there were 77,731 cases (all variants) and 246 deaths (all variants). If I have the right figures (from Daily summary | Coronavirus in the UK (data.gov.uk)), that's 0.3% death rate. That's down from April when it was 0.8%; further down from March when it was 1.7%; and further down from 3.9% in January and February.

EDIT: in June so far the death rate is 0.1%.

We seem to be going in the right direction but we don't know for sure what the impact of Delta will be. Even if it is worse than before, the calculation in the tweet seems to not offer that clarity.
 
I know I said i'd wait to update the hospitalisations figures but I'm not being drawn into an argument about deaths on these numbers. The PHE risk assessment now says the following:

"Iterated analysis continues to show vaccine effectiveness against Delta is higher after 2 doses but that there is a reduction for Delta compared to Alpha. There is uncertainty around the magnitude of the change in vaccine effectiveness after 2 doses of Oxford-AstraZeneca vaccine." [my emphasis]

Below we see, in all likelihood, that hospitalisations are beginning to grow exponentially (i.e. a straight line on a log scale) and the yellow line represents a doubling time of 20 days just to guide the eye until there is enough data to fit sensibly. It's still early days, which is what I have been trying to explain - we just can't expect these to be running away yet. We are, however, going entirely in the wrong direction and hoping that deaths will not follow suit - they're much too low to follow day by day at present.

 
Moving round the ground - masks on. When seated, masks off.

Sorry can't agree with the logic - understand it might stop the beer flowing though ;) Be careful tomorrow won't you, my brother was going today but decided against yesterday, he just had his 2nd dose this week. The game seems to be quite nicely set up if England bowl well this aft.
 
Sorry can't agree with the logic - understand it might stop the beer flowing though ;) Be careful tomorrow won't you, my brother was going today but decided against yesterday, he just had his 2nd dose this week. The game seems to be quite nicely set up if England bowl well this aft.

Ta. I’ve had both doses(AZ) some time ago, and will comply with mask wearing. My view is I’ve been in enough primary schools in the last 8 weeks and not caught anything (no mask wearing in class, just communal areas - schools policy btw)…
 
Indie Sage - theme, should we vaccinate children?


Admissions of children to ICU is higher as a proportion than for seasonal flu.
 
Interestingly there have been no recent infections at my daughters school when it was quite a thing earlier in the year.

Personally I would like the Govt to put it back by two weeks to buy some time for more jabs.
 
Interestingly there have been no recent infections at my daughters school when it was quite a thing earlier in the year.

Personally I would like the Govt to put it back by two weeks to buy some time for more jabs.
I am beginning to feel that is sensible. Assuming cases are increasingly less important per se and it's the undesirable consequences that matter, analysing the admissions and deaths, with the recent data I have, shows a large range of possibilities. There's too much noise in too small a data set. A week or perhaps two might make things clearer. I do acknowledge that government sources will have more comprehensive data so this caution may be misplaced.

The recent admissions graph illustrates the issue well. It is certainly possible to draw an exponential with a troublingly small 20-day doubling time. However you get a very small regression coefficient if you do that, revealing that the curve fit is very poor. Fitting an exponential curve for the highest possible regression coefficient gives a doubling time of 53 days which is much better than 20. However the improved regression coefficient (R² = 0.37) is still too small for high confidence in the model.

EDIT: And analysing deaths data shows even more potential variation between best and worst cases.

Exponential growth models do not inevitably imply fast growth. But this is often the case. Herein lies the dilemma that when things could happen quickly you often need to know from too small a data set that you have to act. The data set as I see it supports neither panic nor complacency: analysis gives too wide a variation between best-case and worst-case predictions. But maybe this does indicate that more data would reduce the variation and so inform a better decision.
 
8 125 cases today (I think the doubling time is looking like 9 days or so), 17 deaths and 147 admissions (8th). The admissions figure is always back-loaded to the end of the week but the increase is undeniable and much worse than my yellow line in recent days. (I could nudge it downwards a spot and parallel but that would make matters worse.) The yellow line represents Alpha behaviour under the previous conditions just as a reminder. Vaccination will just not keep up with this rate for a very considerable time, given the time that it takes to be effective. John, I hope you're right but I think you're mistaken right now. Here's the graph with today's update

 
"Iterated analysis continues to show vaccine effectiveness against Delta is higher after 2 doses but that there is a reduction for Delta compared to Alpha. There is uncertainty around the magnitude of the change in vaccine effectiveness after 2 doses of Oxford-AstraZeneca vaccine." [my emphasis]

Yes I remember that from last week. Put aside the fact that they don’t define vaccine effectiveness. (i.e. effectiveness against what?) Now why would there be uncertainty about AZ but not about Pfizer, given that so much AZ has been used in the UK? Can anyone think it through? I’m just not clear enough about the logic of the situation.
 
Vaccination will just not keep up with this rate for a very considerable time, given the time that it takes to be effective.

Can you spell out what that means? there will be more admissions, but more people are being vaccinated all the time, so I guess that in a short time the rate of growth of admissions should start to decline . . . but I can’t think it through.
 
Yes I remember that from last week. Put aside the fact that they don’t define vaccine effectiveness. (i.e. effectiveness against what?) Now why would there be uncertainty about AZ but not about Pfizer, given that so much AZ has been used in the UK? Can anyone think it through? I’m just not clear enough about the logic of the situation.

Effectiveness compared to their previous analyses.

It's really the hare and the tortoise. The hare seems to be winning comfortably - the vaccine will hopefully catch up eventually but it's slower, much slower, so there will be another peak in cases and deaths. It's not just getting the jabs into arms but the time that it takes to boost immunity thereafter.

The point about AZ is the key concern for me and you jumped on it - it will take time but it seems that there is a weakness in the vaccine even at double dose - it could just be that 2 doses takes longer to take effect than PZ or that AZ is waning, I really don't know.
 
John, I hope you're right but I think you're mistaken right now.
My primary conclusion is that the data does not support any particular conclusion yet. I guess you have a conclusion on the pessimistic end. And I am not saying that is wrong.

There has clearly been a significant decoupling of consequences from cases up to date. That is supported by the data. However, even that will not easily withstand a prolonged rise in cases at the recent 10-day case doubling time, so there will be another wave.

EDIT: 9.7 days doubling time (R² = 0.82).

The uncertain issue is the Delta variant. Looking at the data I think how big the wave will be depends very strongly on assumptions for which we have no solid basis today. I am not predicting which way things will go - just pointing out the wide uncertainly.
 
Status
Not open for further replies.


advertisement


Back
Top