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One-jab efficacy questions

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D_W

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There is very low statistical confidence in the six week observation, so I think its best not to draw any conclusions until more data has emerged. So far the 1st and 2nd dose data it looking to be better than earlier data.
Ditto - what is "slight" or "very slight". Unless it's significant, and then "statistically significant", it doesn't amount to a lot.

The initial news centered around "people don't have detectible antibodies after ____" without addressing whether or not there was an observation in significant levels of community sickness (as in an uptick in symptomatic covid cases, or even more important, moderate and severe).

Too little has been made of the fact that vaccinated folks and those who had covid already don't generally have symptomatic reinfection even when they no longer have detectible antibodies.

Reference back to the WA study which is likely at least 1.2MM person-months of exposure, and probably more than that. 100 proven cases, 10 hospitalizations, 2 deaths with a positive PCR, and hard to know if the deaths were with covid present or because of it. I'd bet much of that cohort was vaccinated earlier and toward the end of that, doesn't have detectible antibodies. Given that much of the cohort will be a very vulnerable segment of the population, I can't imagine how many complete basket cases would be in that group to begin with.

Just taking a whack at some statistics using the excel files from WA state, confirmed cases of covid (i'm guesstimating some) - 40k (vaccinated group is about 1/6th of the population), so normalizing the rest of the group and ignoring everything else (which isn't wholesome, but it's better than nothing), figure 100 vaccinated cases vs. 8000 per 1/6th slice of unvaccinated population)

deaths - 185 total (2 from vaccinated, or was it 3? assume 2). about 37 per slice (and on average, those slices are less vunlerable than the vaccinated slices - but who knows, maybe the vulnerable did more to avoid covid - too many variables to tell for sure, but 5 slices averaging 37 against 2 is stark)

hospitalizations - 10 for the vaccinated slice, 2678 for all others, or 536 per equivalent population slice vs. the 10.

If the data could be any better, I can't reasonably see how. Given the case load outside of the vaccinated population, it would be interesting to guess what the number of vaccinated cases would be if those folks didn't have to live among the unvaccinated. It would likely be very tiny.
 

D_W

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(it's not just death, either - there will be tons of morbidity among the non-deaths, and even some disabling conditions for people who weren't ever hospitalized).
 

Jacob

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Down for AZ jab 2 next week! No worries.
 

Chris152

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'A "significant" cluster of the South African Covid-19 variant has been found in two areas of south London where surge testing has been implemented.'
Does anyone have a link to up-to-date info on how effective the AZ vaccine is in relation to that variant? Latest I can find is the small study done in SA, reported in February, which doesn't tell us a lot (maybe 12% effective against mild/ moderate disease).
 

TominDales

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There is not a lot of data yet. Personally I see this emphasis on surge testing as a sign our government and PH England are taking the virus seriously and doing what is necessary to protect the population from Covid. If we had done this 14 months ago we would have seen far less infections and deaths. I don't read the surge testing as a panic measure, but part of the normal PH responsive that will be needed until Covid is supressed worldwide we will need to do this and other measures to keep new variants down - see it as business as usual.

As for the data - its very sketchy and I would not read too much into it at the moment.
Here is an Israeli newspaper report. Indicating that with vaccinated vs unvaccinated people the prevalence of the SA variant in infected patients was 8 times that of the unvaccinated. - take the 8 times with a pinch of salt. Real-world Israeli study shows SA variant can break through Pfizer vaccin
So few people had Covid that the sample was too small to rely on the data. There methodology looks sound, but with only 400 cases it was just too few to make any sensible numerical conclusion that 8 times could in reality be only 2 or 3 times if there had been just a couple more or less cases in the study!! so BEWHARE OF NEWPAPER HEADLINES editors run with these numbers to get us to read the article.

In this JP article, they compare vaccinated vs vaccinated patients who tested positive for covid and try to see if there is a difference in SA variant, ie assume the undying SA variant is in the unvaccinated cohort and then see what the effect of vaccination is in the proportion of the vaccinated cohort.

The SA variant was 1% of patents ie 4 people in total in the unvaccinated population - so very small numbers. If Pfizer is 5% ineffective against Covid in general ie 95% effective (seems to be the consensus at the moment) that would mean is nearer 40% ineffective against SA (probably an over estimate) so vaccine effectiveness against inaction is only about 60% effective, probably high enough for getting population immunity eventually. I would treat this as a crude guess as there is very little quantitative data published you only needed one or two less people in the study to increase the vaccine effectiveness to 80% or more, remember to get 400 cases of Covid in vaccines people they would have needed 20 times as many people to get their 400 cases and they may have stubled accross a gropu who had come back from SA. We need to be careful not to read too much into the data. Your can see where the 8x number came from, but it could be much less. There were some reports that the AZ vaccine is more effective than Pfizer against the SA variant (maybe due to T cell response), but that could also be a statistical anomaly due to small numbers of cases.

SA variant is not as transmissible as the UK variant. This is highly significant as transmissibility increases morbidity as it leads to greater exponential growth of the disease. The Kent variant is much more transmissible, but UK data seems to show vaccine is highly effective against this variant. So while the SA variant may be less susceptible to vaccination, it is more susceptible to being supressed by all forms of action such as social distancing.

What has not appeared yet, is the hospitalisation and death rates from those vaccinated, I would expect those rates to be very low for the reasons given on the overall effect of vaccination.

If your question is - am I worried by this?
Personally not especially, its what we expected to happen. The UK is in a much better place than 12 months ago. The testing, social distancing / mask measures are well established and effective. The at long last government seems to be taking 'track-and-trace' for new variants as a national priority. We hare rolling out effective vaccines (if only 60+% effective against the SA variant) and new variant vaccines are being readied at speed for release in the autumn. Also the UK and many countries are now regularly sequencing the RNA of the virus from PCR tests (10% of all positive samples are sequenced in the UK). This provides an early warning for new variants and picked up the Kent variant very quickly in the autumn.


It is too early to say much yet on the SA variant, its likely to be one of many that we will face over the next few years.
Many methods to suppress the virus will need to continue for the foreseeable future - we cant rely on vaccines alone. Once infection is at a low level the vaccine is pushing down on a low number. If we let the virus spread then the vaccine has more of an up-hill effect. So lockdown can be safely eased as we have many measures to control covid and lead relatively normal lives. Lockdown is a last resort when you lose control of it through these 'ordinary every days measures.

Opening up of schools this time round has gone well in the UK, with infection rates remaining low and stable. Israel has shown that you can successfully re-open an economy once infection levels are down and vaccination is well established ie >50% of the population. (Cf Chile where they opened up too early). Furthermore if a new variant appears we know how to lockdown if needed to supress it.

Not until the virus is supressed worldwide will be fully in the clear, so for the next few years we need to be vigilant, but maybe 'keep calm and carry on' until we fully suppress the virus globally is the motto.
 

D_W

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If the Pfizer vaccine was very ineffective against the S.A. variant, there would be a lot more of the S.A. variant in israel.
 

Chris152

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Point taken about the govt's focus now on tracking and tracing, hopefully people will use and adhere to it.

It is about personal risk but more, for the moment at least, about how the SA variant could spread. I remember when Van-Tam explained how the vaccines we have limit the variants we have (it was a while back - essentially Covid 'Original' and Kent), how the SA variant was very marginal here and it felt like, so long as we kept such variants that cause problems for the vaccine at bay til adapted boosters could be brought in, all should be under control. The question was raised at the time: if the Kent variant is suppressed, the SA variant now has an advantage if the vaccines (esp AZ?) aren't very effective at stopping it.

Looking at the news about lifting of restrictions at the mo, I can't help but feel there's a fair chance people are starting to forget the 'ordinary, everyday measures'. It's just one bloke's comment while out celebrating, but BBC reports: "There is a wonderfully raucous hysteria everywhere. It's very celebratory. There is very little social distancing. A distinct sense that people feel the Covid restrictions have ended".
Hm.
 

TominDales

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Point taken about the govt's focus now on tracking and tracing, hopefully people will use and adhere to it.

Looking at the news about lifting of restrictions at the mo, I can't help but feel there's a fair chance people are starting to forget the 'ordinary, everyday measures'. It's just one bloke's comment while out celebrating, but BBC reports: "There is a wonderfully raucous hysteria everywhere. It's very celebratory. There is very little social distancing. A distinct sense that people feel the Covid restrictions have ended".
Hm.
Let's hope people haven't forgotten, the messaging from Whitty, BJ and compnahy, they are rightly advocating for cautious steady opening, (he seems to have dropped the optimism talk) with 5 week delays between phases to allow for the data to come in and policy to be adjusted.
BUT, if we as a population forget the everyday measures we will end up back in a lockdown situation.
The problem is , the UK (and all developed economies in West Europe US etc) have very open economies our supply chains and pattern of trade are build that way, we cant do an Australia or NZ without closing huge sectors of the economy, we therefore need to adapt to the virus. During the last lockdown business did do that, the economy didn't shrink as fast as economists feared. If we open up cautiously and keep infections down we can lead fairly normal lives, but our trading patterns, our desire as a nation for summer sun in the south will leave us vulnerable to new variants. The variants will have to be dealt with as they arise. Rapid T&T or surge T&T as they call it will be essential as will other practical everyday measures. Let's hope commons sense prevails.
 

Chris152

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This is some very good-looking news on first jab:
'Researchers analysed the cases of 74,405 people admitted to hospital with the virus between September and March and found that only 32 had received a jab at least three weeks before.
University of Liverpool Professor Calum Semple, who is a member of SAGE, said he was "absolutely delighted" with the results. ...
He added that the findings were even more remarkable because they related to those who had received just one jab. ...
The vaccines are said to be 90% effective at keeping those infected out of hospital after just one dose, according to findings reportedly relaid to the government.'
Reading around, it's very clear that level of effectiveness is only reached after a few weeks, admissions are much higher after less than three weeks after first jab.
The 90% effective at keeping those already infected out of hospital answers my first question, assuming they've worded that correctly.
 

Jonm

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This is some very good-looking news on first jab:
'Researchers analysed the cases of 74,405 people admitted to hospital with the virus between September and March and found that only 32 had received a jab at least three weeks before.
University of Liverpool Professor Calum Semple, who is a member of SAGE, said he was "absolutely delighted" with the results. ...
He added that the findings were even more remarkable because they related to those who had received just one jab. ...
The vaccines are said to be 90% effective at keeping those infected out of hospital after just one dose, according to findings reportedly relaid to the government.'
Reading around, it's very clear that level of effectiveness is only reached after a few weeks, admissions are much higher after less than three weeks after first jab.
The 90% effective at keeping those already infected out of hospital answers my first question, assuming they've worded that correctly.
Looks fantastic news but but it is the Mirror. Refers to comments by University of Liverpool Professor Calum Semple but does not actually give details of who did the study. So we have a journalists report on something undertaken by persons unknown. My searches only picked up similar comments in other newspapers, nothing substantial.

I hope it is correct but would like to see some more details.
 

Chris152

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Looks fantastic news but but it is the Mirror. Refers to comments by University of Liverpool Professor Calum Semple but does not actually give details of who did the study. So we have a journalists report on something undertaken by persons unknown. My searches only picked up similar comments in other newspapers, nothing substantial.

I hope it is correct but would like to see some more details.
It was originally released to the Telegraph, maybe you can access that?
Sky news has:

'Data reveals impact of one vaccine dose on COVID infections

A key government scientist has said that real-world data shows coronavirus vaccines are "working really well".

Around 74,000 people were admitted to hospitals with the virus in recent months, but only 32 of them were vaccinated, official data from March shows.

Speaking on BBC Radio 4's Today programme Professor Calum Semple, one of the scientists advising the government on COVID-19, said the results are "very good news".

Prof Semple said researchers looked "very carefully" at the hospital records of the 74,000 people in the data sample.

They worked out that 43,000 had been admitted after vaccinations started. Within that number just under 2,000 people that had received a jab. They then looked at how many days there were between receiving the vaccine and the onset of their symptoms.

Prof Semple said: "Most people admitted had caught their infection within a week on either side of vaccination and then there was a really sharp drop off in numbers, so that, after three weeks after being vaccinated, we could only count 32 people out of the 2,000 that had been vaccinated.”

It works out at less than 2%, and that is in the elderly population.

"It's really good real-world data showing that this vaccine works and one dose works really well," he said.'
 

Jonm

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Friday Morning last week my wife received a text to come for second jab, either same day or week following Monday. They presumably were trying to fill empty slots on the friday. We were going out so booked an appointment to suit. Arrived and they could fit me in as well.

Time from text to us both receiving the jab, just over one hour!

Felt a tiny prick from the injection (AZ) and no reaction whatsoever, not even a sore arm.
 

Rorschach

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It's very good news to see the lower hospital numbers for those vaccinated, especially in the older age brackets.
 

Terry - Somerset

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I would have expected that the scientists would be crawling all over the data to understand the effectiveness of the vaccine rollout.

This must have included data on hospital admissions and deaths recorded with Covid in respect of individuals who had been previously vaccinated.

This is so blindingly obviously an important data set that I can only come to one of two conclusions - either they are truly incompetent (which I doubt) or the data is being withheld (which seems far more likely).
 

D_W

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This data is excellent news, and is what I've been crowing about because it's similar to Washington State. 1.2 million vaccinated there and over 2 months, only 10 of those were admitted for serious covid cases. 10 out of 1.2 million!

It's time to stop the bs fake news and scare garbage about variants and put all hands on deck to promote as many vaccinations as possible. Does anyone think a data pool of 1.2 million doesn't include some people with variants?

And that 10 admissions includes most of the vulnerable population. It's a very real question to ask if all of Washington State was vaccinated, would there even be enough virus density for the virus to survive? 45,000 tested positive over that time and 100 of the positive tests were in the vaccinated group. 100! I'd bet zero or near zero acquired their case from another vaccinated person.
 

Jonm

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It was originally released to the Telegraph, maybe you can access that?
Sky news has:

'Data reveals impact of one vaccine dose on COVID infections

A key government scientist has said that real-world data shows coronavirus vaccines are "working really well".

Around 74,000 people were admitted to hospitals with the virus in recent months, but only 32 of them were vaccinated, official data from March shows.

Speaking on BBC Radio 4's Today programme Professor Calum Semple, one of the scientists advising the government on COVID-19, said the results are "very good news".

Prof Semple said researchers looked "very carefully" at the hospital records of the 74,000 people in the data sample.

They worked out that 43,000 had been admitted after vaccinations started. Within that number just under 2,000 people that had received a jab. They then looked at how many days there were between receiving the vaccine and the onset of their symptoms.

Prof Semple said: "Most people admitted had caught their infection within a week on either side of vaccination and then there was a really sharp drop off in numbers, so that, after three weeks after being vaccinated, we could only count 32 people out of the 2,000 that had been vaccinated.”

It works out at less than 2%, and that is in the elderly population.

"It's really good real-world data showing that this vaccine works and one dose works really well," he said.'
Thanks for the extra info. The telegraph article is behind a paywall. Here is a link to an article which gives the same figures.
As you said, the origin of this is Professor Calum Semple talking on BBC Radio 4's Today programme. Good reliable source.

UK Hospitalisations between Dec 2020 and March 2021

  • total hospitalisation 74 405
  • number of hospitalisation before vaccination available about 31000
  • number of hospitalisation after vaccination available about 43000
  • number of hospitalisation after receiving vaccination about 2000
  • number of hospitalisation with Covid symptoms occurring three weeks or more after vaccination, 32 number
So really good news but does not give numbers vaccinated.

If we assume that the end date is towards the end of March then three weeks before is say, end of February. I attach a graph of total vaccinations and that gives a figure of 20 million vaccinated by end of Feb.

So that is 32 hospitalisations out of 20 million vaccinated first dose, once vaccine is given time to become effective. So vaccine is 99.99984% effective against hospitalisations.

If true that is wonderful news but it seems too good to be true! I can see end of feb being too late, Covid takes a bit longer to turn in to a hospital case, perhaps middle of Feb, but still 15 million vaccinated then so makes little difference. Not sure why this information is not more widely available, is it incorrect or being suppressed?

D7564419-DFA2-4549-B169-9E7C0B94EB30.png
 

D_W

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There's usually some lag in the hospitalization numbers, and other possible confounding factors, but in keeping with the washington state numbers, 1.2MM fully vaccinated (so a more strict cohort) and 10 hospitalizations from that cohort in two months (keep in mind, that's nearly all of the elderly population). 2 deaths deemed due to covid, which is certainly possible. One would wonder just how many health basket cases there are in a group of that size, though, who may also get covid because they don't respond to the covid vaccine for other reasons (e.g., people on immunosuppressive drugs).

But my comment above still stands - based on the confirmed cases of covid in the wa state cohort, only 100, it's likely that one or none of those cases were from other vaccinated folks. If the vaccinated folks aren't giving each other covid, and kid to kid transmission is very rare, then what would seem to be the smart thing to do?
 

Jake

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I would have expected that the scientists would be crawling all over the data to understand the effectiveness of the vaccine rollout.
They are, it is looking really good so far on the variants currently in play. The game now is to (i) avoid causing immune pressure by having high prevalence (amongst the less vulnerable and hence non-vaccinated groups) mixing with vaccinated groups (which would promote evolutionary success of variants which escape vaccine immunity) and (ii) within that, avoid spread of variants for which the current vaccines appear not to be as effective.

That's why the concern about SA variant in particular (where AZ pulled their clinical trial because the interim trial data was showing such poor protection that it was considered unethical to continue the trial). Could be reasons etc, nothing definitively proven, but its a serious concern prior to booster development and roll-out.

Overall we need to get vaccine roll out going world wide. Not just for humanity reasons, also to reduce the mutation numbers game.
 

D_W

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the interesting thing about the SA virus concern is that while it does appear to have some success breaking through (relative, and maybe yet to be proven statistically significant), the numbers would suggest that vaccine success aainst it may be 85-90% instead of 95-98% or some such thing.

32 hospitalizations seems low for that cohort, but again, that may be lagging. 10 out of 1.2 million for washington state, but we are not talking about big numbers in either case, so both may be relevant.

While health care utilization is higher here than the UK, I don't know that hospitalization is as the vast increase in facilities in the last 20 years has been in non-hospitals or non-admission type scenarios. Often due to carriers demanding less admission when it's not needed as well as surgical providers trying to get procedures off site where they can specify a higher reimbursement than in hospitals.
 
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