Covid vaccine effectiveness.
Discussion
There is a science question in this - I'll just 'set the scene' first.
I've just seen a post on Facebook this morning which made me groan a little, but also raised a question in my mind.
In the post, the person claims that during development, subjects were not actually infected with Covid, but just given the vaccine, which makes no sense (to me).
So, on to the *science* part of my question.
Would I be correct in assuming that scientists know what the vaccine needs to contain in order to prevent the virus attacking a person's immune system, hence they have no need to infect the subjects, but just have to test that administering the vaccine doesn't result in any unwanted side effects?
Facebook post below: (This individual has been particularly outspoken on Covid issues but I know is no expert..)
I've just seen a post on Facebook this morning which made me groan a little, but also raised a question in my mind.
In the post, the person claims that during development, subjects were not actually infected with Covid, but just given the vaccine, which makes no sense (to me).
So, on to the *science* part of my question.
Would I be correct in assuming that scientists know what the vaccine needs to contain in order to prevent the virus attacking a person's immune system, hence they have no need to infect the subjects, but just have to test that administering the vaccine doesn't result in any unwanted side effects?
Facebook post below: (This individual has been particularly outspoken on Covid issues but I know is no expert..)
Faceache post said:
Now let’s get this clear, I’m not an anti vaxxer, vaccines have done wonderful things and will continue to do so.
But
All these efficacy claims of Coronavirus vaccines are without doubt absolute bulls
t.
Let me explain why in words of not many syllables for those of you who don’t get it.
Efficacy (I know that’s a long word) (google it) is proven by exposure to whatever you are treating.
Now let’s say they gave 50,000 people the vaccine in trials.
Did they give those 50,000 people a “get out of jail free card to go and mingle and go to the pub and live normal lives?”
Answer is no.
Therefore no efficacy is proven at all.
Did they expose all 50,000 people to the virus deliberately?
Answer is no.
Therefore no efficacy can be derived at all.
Therefore, safety concerns aside, there is virtually no data to say that the vaccine works in any way shape or form.
So with the safety concerns as well, think carefully before you have a vaccine that’s unproven, could be unsafe and yet you have no legal redress if you have life changing after effects, because you can’t sue anyone for that legal redress.
My advice?
Wait a couple of years while we actually have data.
Of course by then we’ll all be shielding from a nasty strain of the common cold.
Because it might kill us...
But
All these efficacy claims of Coronavirus vaccines are without doubt absolute bulls
t. Let me explain why in words of not many syllables for those of you who don’t get it.
Efficacy (I know that’s a long word) (google it) is proven by exposure to whatever you are treating.
Now let’s say they gave 50,000 people the vaccine in trials.
Did they give those 50,000 people a “get out of jail free card to go and mingle and go to the pub and live normal lives?”
Answer is no.
Therefore no efficacy is proven at all.
Did they expose all 50,000 people to the virus deliberately?
Answer is no.
Therefore no efficacy can be derived at all.
Therefore, safety concerns aside, there is virtually no data to say that the vaccine works in any way shape or form.
So with the safety concerns as well, think carefully before you have a vaccine that’s unproven, could be unsafe and yet you have no legal redress if you have life changing after effects, because you can’t sue anyone for that legal redress.
My advice?
Wait a couple of years while we actually have data.
Of course by then we’ll all be shielding from a nasty strain of the common cold.
Because it might kill us...
The efficacy claims made for the vaccines have been based on the infection rates of the participants, in a double blind trial.
Effectively you give 200 people an injection, 100 placebo and 100 vaccines to be trialled. Then follow those people over a period of time to see if 1: they catch COVID and 2: they suffer any side effects. The efficacy is the delta between the placebo people catching the disease the vaccinated people catching it. So if all of the placebo people catch it, and only 5 of the vaccinated people catch it, it would have a 95% efficacy.
The trials are huge and the definitions of catching it are more comprehensive but that is the general idea.
There was no intentional infection, but as so many people have been catching it in the population, and the trial groups were so large, it is statistically almost certain that the infection rate variance is caused by the vaccination.
This gives a good introduction for the lay person. (Of which I am one!)
https://www.jnj.com/innovation/the-5-stages-of-cov...
Effectively you give 200 people an injection, 100 placebo and 100 vaccines to be trialled. Then follow those people over a period of time to see if 1: they catch COVID and 2: they suffer any side effects. The efficacy is the delta between the placebo people catching the disease the vaccinated people catching it. So if all of the placebo people catch it, and only 5 of the vaccinated people catch it, it would have a 95% efficacy.
The trials are huge and the definitions of catching it are more comprehensive but that is the general idea.
There was no intentional infection, but as so many people have been catching it in the population, and the trial groups were so large, it is statistically almost certain that the infection rate variance is caused by the vaccination.
This gives a good introduction for the lay person. (Of which I am one!)
https://www.jnj.com/innovation/the-5-stages-of-cov...
They did not do challenge trials in humans, because that would have been highly unethical.
They compared naturally occurring rates of infection and sickness between volunteers who had been given the vaccine and volunteers who had been given the placebo. Neither volunteers or scientists knew which group any given person was in.
You should report the Facebook post as misinformation.
They compared naturally occurring rates of infection and sickness between volunteers who had been given the vaccine and volunteers who had been given the placebo. Neither volunteers or scientists knew which group any given person was in.
You should report the Facebook post as misinformation.
Oxford-AstraZeneca ChAdOx1 nCoV-19 (AZD1222)
The ChAdOx1 nCoV-19 vaccine was developed by the University of Oxford and AstraZeneca. The vaccine works by delivering the genetic code of the SARS-CoV-2 spike protein to the body’s cells, similarly to the BNT162b2 vaccine. Once inside the body, the spike protein is produced, causing the immune system to recognise it and initiate an immune response. This means that if the body later encounters the spike protein of the coronavirus, the immune system will recognise it and destroy it before causing infection.
This Oxford-AstraZeneca vaccine uses the ChAdOx1 technology, which has been developed and optimised by the Jenner Institute over the last 10 years. This type of vaccine technology has been tested for many other diseases such as influenza (flu) and middle east respiratory syndrome (MERS), another type of coronavirus. More information about viral vectored vaccines is below.
The ChAdOx1 nCoV-19 vaccine has been tested by the University of Oxford in clinical trials of over 23,000 people in the UK, Brazil and South Africa. AstraZeneca are also running a further trial with 40,000 people in the USA, Argentina, Chile, Columbia and Peru.
Interim results from the UK and Brazil trials showed that the vaccine can prevent 70.4% of COVID-19 cases. This was calculated across two different groups of people, who received two different dose regimens. The vaccine was shown to prevent 73% of cases in individuals with at least one underlying health condition. The vaccine has also been shown to produce similar immune responses in older adults when compared with young, healthy individuals, although the efficacy data for this group is not yet available.
The ChAdOx1 nCoV-19 vaccine is given as a two-dose course, which is given as an injection into the upper arm. The second dose is given 4-12 weeks after the first dose.
You do not have to look hard to find the scientific detail. The misinformation spread by the by the anti vaxxers only gains traction because it is blindly accepted. This interestingly is what the anti vaxxers accuse the gullible public of.
The ChAdOx1 nCoV-19 vaccine was developed by the University of Oxford and AstraZeneca. The vaccine works by delivering the genetic code of the SARS-CoV-2 spike protein to the body’s cells, similarly to the BNT162b2 vaccine. Once inside the body, the spike protein is produced, causing the immune system to recognise it and initiate an immune response. This means that if the body later encounters the spike protein of the coronavirus, the immune system will recognise it and destroy it before causing infection.
This Oxford-AstraZeneca vaccine uses the ChAdOx1 technology, which has been developed and optimised by the Jenner Institute over the last 10 years. This type of vaccine technology has been tested for many other diseases such as influenza (flu) and middle east respiratory syndrome (MERS), another type of coronavirus. More information about viral vectored vaccines is below.
The ChAdOx1 nCoV-19 vaccine has been tested by the University of Oxford in clinical trials of over 23,000 people in the UK, Brazil and South Africa. AstraZeneca are also running a further trial with 40,000 people in the USA, Argentina, Chile, Columbia and Peru.
Interim results from the UK and Brazil trials showed that the vaccine can prevent 70.4% of COVID-19 cases. This was calculated across two different groups of people, who received two different dose regimens. The vaccine was shown to prevent 73% of cases in individuals with at least one underlying health condition. The vaccine has also been shown to produce similar immune responses in older adults when compared with young, healthy individuals, although the efficacy data for this group is not yet available.
The ChAdOx1 nCoV-19 vaccine is given as a two-dose course, which is given as an injection into the upper arm. The second dose is given 4-12 weeks after the first dose.
You do not have to look hard to find the scientific detail. The misinformation spread by the by the anti vaxxers only gains traction because it is blindly accepted. This interestingly is what the anti vaxxers accuse the gullible public of.
otolith said:
They did not do challenge trials in humans, because that would have been highly unethical.
They compared naturally occurring rates of infection and sickness between volunteers who had been given the vaccine and volunteers who had been given the placebo. Neither volunteers or scientists knew which group any given person was in.
You should report the Facebook post as misinformation.
They haven't done challenge trials yet, but such things are being investigated.They compared naturally occurring rates of infection and sickness between volunteers who had been given the vaccine and volunteers who had been given the placebo. Neither volunteers or scientists knew which group any given person was in.
You should report the Facebook post as misinformation.
https://www.gov.uk/government/news/expert-partners...
LOL, fell out with a friend who claimed the vaccines have only been trialled with people infected with a very mild strain of Covid 19!
But hijacking this thread to ask two more questions. First question is why is a vaccine not also a cure? If the body starts releasing defences for something surely that should also be a cure?
Question two is specific to Covid 19, read somewhere that the infection has only a life of about 4 hours when on copper but something like 36 hours when it is on stainless steel, why the difference?
But hijacking this thread to ask two more questions. First question is why is a vaccine not also a cure? If the body starts releasing defences for something surely that should also be a cure?
Question two is specific to Covid 19, read somewhere that the infection has only a life of about 4 hours when on copper but something like 36 hours when it is on stainless steel, why the difference?
The vaccine is not also a cure because it doesn’t make you instantly immune. You’re already in the process of gaining immunity when you’re naturally infected, but it takes time.
The only example I can think of where that works is rabies, because it takes a long time from being bitten to becoming symptomatic. Once you’re symptomatic, you’re a goner.
The only example I can think of where that works is rabies, because it takes a long time from being bitten to becoming symptomatic. Once you’re symptomatic, you’re a goner.
This is one of the better interviews /peices I've read on this recently ;
https://www.google.com/amp/s/www.repubblica.it/cro...
CEO AZ telling it like it is.
So, you can assure that this vaccine is efficient for the elderly?
“The issue with the elderly data is not so much whether it works or not. It´s that we have today a limited amount of data in the older population. You have to think that the program we have today was run by Oxford, it was the Oxford program. And Oxford is an academy group. They´re very ethical, and very academic. So they didn´t want to vaccinate older people until they had accumulated a lot of safety data in the 18 to 55 group. They said it was not ethical to vaccinate old people until they had enough safety data in younger people. Other companies took this risk, went ahead and vaccinated older people faster or earlier. If you start earlier, you have more data. Essentially, because Oxford started vaccinating older people later, we don´t have a huge number of older people who have been vaccinated. So that's what the debate is. But we have strong data showing very strong antibody production against the virus in the elderly, similar to what we see in younger people. It's possible that some countries, out of caution, will use our vaccine for the younger group. But honestly, it is fine. There's no enough vaccines for everybody. So if they want to use another vaccine for older people and our vaccine for younger people, what´s the problem? It’s not a problem. We're trying to deal with this crisis together. If you add up our capacity, plus the Pfizer capacity, plus the Moderna capacity, there’s not enough in the world. There's not enough for the entire world. I personally think that the group of people who are between 50 and 70 are an important group to protect. If you are 50, 60, you need to be protected. Many people may have hypertension, overweight, you need to protect them. And the younger people, at some point, we need to protect them also. So, even though no country has done so so far, it’s possible that some countries will say: we will not use the AZ vaccine in older people until we have the US data confirming that it is indeed to be used in older people. Different groups or countries will take different approaches. The UK said: we believe it works in older people, we’re going to use it in older people”.
But how efficient is the AZ vaccine for people over 65? Can you give us a number?
"I don’t have the number in mind, to be honest with you, because the team has been finalizing the analysis. We had an interim analysis based on the November analysis of the data. What you do when you run a big trial like this is you do interim analysis. Pfizer did an interim analysis, so did Moderna. So we had an interim analysis with the data as they were in November, with a number of elder people, and then we had a final analysis in December, with more than 200 cases of infections, so a very high number of infections. And so the efficacy in that group, I don't remember precisely the number, it´s comparable to what you had in younger people".
"The problem is that it is a statistics debate, in a way. When you run a trial, you then say, the result es X%. And then you say, there is a confidence interval around this result. You may have heard this expression, we have 95% confidence interval, which is around this estimate of X%, what could be the lowest and what could be the highest. And if you have a lower number of people in the trial, then the confidence interval is very wide. So you have a point estimate, but the reality is that it could be higher or it could be lower. And that´s why people say, we don´t know, we can´t be sure, because we don´t have enough patients and therefore you have a large confidence interval".
"So the answer to this is that the data is showing good level of antibodies in elderly as you see in younger people, so we believe other regulators concluded the point estimate is real, even though the confidence is large. So it´s comparable to what we had in younger people. The point is that what´s important as far as the efficacy…at the end of the day, what is really important is the protection against severe disease and hospitalization. Because if you can stop people from being severely sick, and importantly, if you stop them from going to the hospital, the whole thing becomes completely manageable. The hospitals are not overwhelmed, and people may cough a bit, or maybe run a little bit of fever, but they get on with their lives, as with the flu. That´s what you really want to do. Eliminate severe disease and hospitalization. Get rid of it. And, in our study, we have 100% protection against severe disease and hospitalization".
So a few things here I think are interesting.
1. Yes you have to rely on random infections to show efficacy vs control. The more infections, the narrower (better) your confidence.
2. All the hootenanny around poor performance in over 65 was due on a very small sample and only, IIRC one case of covid + in both vaccine and control, so the results were basically noise - didnt stop media from peddling rubbish, however.
3. You can measure antibody response in a petri dish from a subjects blood sample. This is how vaccines are generally tested as part of trials. Results from these tests can let you "read across" different patient cohort groups to infer likely efficacy based on blood testing of a group without it being too large or exposed to covid at all.
Basically its a lot of patients, some. Vaccinated and some not, a lot of lab work, and a lot of statistics. Combine the lot and you can make pretty accurate predictions without full test coverage. The predictions, from what I can see, unsurprisingly seem to have been correct. In time the real numbers will be known, but for now, clearly, vaccination works. It works at reducing likelihood of getting covid, but most importantly, even if you still get covid afyer being Vaccinated, your odds of ending up in ICU are massively diminished.
Not getting Vaccinated is just really silly. I'm under 40 and will take it at first opportunity. I'll let those more vulnerable get theirs first, then I'll take mine. Not because I have high likelihood of getting seriously ill from Covid , I don't, but this is so infectious and can harm those who have weak immune systems and some cannot get Vaccinated for health reasons, that I think, as a population, we should do what we can to minimise covid in the wild. It's not fair to the frail and immune suppressed to have to live in fear of going outside for the rest of their lives, and from a selfish perspective we also want to minimise prevalence to minimise likelihood of serious variants mutating, that could result in more lockdown loops.
Just get Vaccinated when your time is called, its ignorant, idiotic and selfish not to IMO.
https://www.google.com/amp/s/www.repubblica.it/cro...
CEO AZ telling it like it is.
So, you can assure that this vaccine is efficient for the elderly?
“The issue with the elderly data is not so much whether it works or not. It´s that we have today a limited amount of data in the older population. You have to think that the program we have today was run by Oxford, it was the Oxford program. And Oxford is an academy group. They´re very ethical, and very academic. So they didn´t want to vaccinate older people until they had accumulated a lot of safety data in the 18 to 55 group. They said it was not ethical to vaccinate old people until they had enough safety data in younger people. Other companies took this risk, went ahead and vaccinated older people faster or earlier. If you start earlier, you have more data. Essentially, because Oxford started vaccinating older people later, we don´t have a huge number of older people who have been vaccinated. So that's what the debate is. But we have strong data showing very strong antibody production against the virus in the elderly, similar to what we see in younger people. It's possible that some countries, out of caution, will use our vaccine for the younger group. But honestly, it is fine. There's no enough vaccines for everybody. So if they want to use another vaccine for older people and our vaccine for younger people, what´s the problem? It’s not a problem. We're trying to deal with this crisis together. If you add up our capacity, plus the Pfizer capacity, plus the Moderna capacity, there’s not enough in the world. There's not enough for the entire world. I personally think that the group of people who are between 50 and 70 are an important group to protect. If you are 50, 60, you need to be protected. Many people may have hypertension, overweight, you need to protect them. And the younger people, at some point, we need to protect them also. So, even though no country has done so so far, it’s possible that some countries will say: we will not use the AZ vaccine in older people until we have the US data confirming that it is indeed to be used in older people. Different groups or countries will take different approaches. The UK said: we believe it works in older people, we’re going to use it in older people”.
But how efficient is the AZ vaccine for people over 65? Can you give us a number?
"I don’t have the number in mind, to be honest with you, because the team has been finalizing the analysis. We had an interim analysis based on the November analysis of the data. What you do when you run a big trial like this is you do interim analysis. Pfizer did an interim analysis, so did Moderna. So we had an interim analysis with the data as they were in November, with a number of elder people, and then we had a final analysis in December, with more than 200 cases of infections, so a very high number of infections. And so the efficacy in that group, I don't remember precisely the number, it´s comparable to what you had in younger people".
"The problem is that it is a statistics debate, in a way. When you run a trial, you then say, the result es X%. And then you say, there is a confidence interval around this result. You may have heard this expression, we have 95% confidence interval, which is around this estimate of X%, what could be the lowest and what could be the highest. And if you have a lower number of people in the trial, then the confidence interval is very wide. So you have a point estimate, but the reality is that it could be higher or it could be lower. And that´s why people say, we don´t know, we can´t be sure, because we don´t have enough patients and therefore you have a large confidence interval".
"So the answer to this is that the data is showing good level of antibodies in elderly as you see in younger people, so we believe other regulators concluded the point estimate is real, even though the confidence is large. So it´s comparable to what we had in younger people. The point is that what´s important as far as the efficacy…at the end of the day, what is really important is the protection against severe disease and hospitalization. Because if you can stop people from being severely sick, and importantly, if you stop them from going to the hospital, the whole thing becomes completely manageable. The hospitals are not overwhelmed, and people may cough a bit, or maybe run a little bit of fever, but they get on with their lives, as with the flu. That´s what you really want to do. Eliminate severe disease and hospitalization. Get rid of it. And, in our study, we have 100% protection against severe disease and hospitalization".
So a few things here I think are interesting.
1. Yes you have to rely on random infections to show efficacy vs control. The more infections, the narrower (better) your confidence.
2. All the hootenanny around poor performance in over 65 was due on a very small sample and only, IIRC one case of covid + in both vaccine and control, so the results were basically noise - didnt stop media from peddling rubbish, however.
3. You can measure antibody response in a petri dish from a subjects blood sample. This is how vaccines are generally tested as part of trials. Results from these tests can let you "read across" different patient cohort groups to infer likely efficacy based on blood testing of a group without it being too large or exposed to covid at all.
Basically its a lot of patients, some. Vaccinated and some not, a lot of lab work, and a lot of statistics. Combine the lot and you can make pretty accurate predictions without full test coverage. The predictions, from what I can see, unsurprisingly seem to have been correct. In time the real numbers will be known, but for now, clearly, vaccination works. It works at reducing likelihood of getting covid, but most importantly, even if you still get covid afyer being Vaccinated, your odds of ending up in ICU are massively diminished.
Not getting Vaccinated is just really silly. I'm under 40 and will take it at first opportunity. I'll let those more vulnerable get theirs first, then I'll take mine. Not because I have high likelihood of getting seriously ill from Covid , I don't, but this is so infectious and can harm those who have weak immune systems and some cannot get Vaccinated for health reasons, that I think, as a population, we should do what we can to minimise covid in the wild. It's not fair to the frail and immune suppressed to have to live in fear of going outside for the rest of their lives, and from a selfish perspective we also want to minimise prevalence to minimise likelihood of serious variants mutating, that could result in more lockdown loops.
Just get Vaccinated when your time is called, its ignorant, idiotic and selfish not to IMO.
OP - it might be wise to look at what is in the vaccine and what it aims to achieve once in the human body.
I'm no expert but I think this is the general scope - Different vaccines do things in different ways, but generally once the genome of the virus is known and the shape of the virus is also known and modelled, the development of anti-body inducing proteins (RNA etc) can be designed to prevent the virus from attaching to cells within the lungs and other parts of the body.
The new vaccine will therefore contain newly designed proteins that stimulate the person in to producing an anti-body response, and as such the anti-bodies that the person produces are intended to be such that will attach to the proteins in the vaccine in a similar way that they would attach to the virus. Therefore if the person were to catch the virus, the immune system will identify the shape and deploy the anti-bodies which will be effective against it.
So, true to say that people were not injected with the covid19, there was no need to. Because covid19 had already been sequenced and modelled and a vaccine then designed combat it. (This is the great thing with modern bio-chemistry and the pharmaceutical industry in what it is today).
The efficacy value of say 90% is such that 90% of those vaccinated will develop the intended immune response in producing the intended anti-bodies in readiness for if they were to catch covid19.
It is not as some people think, that if 100 people caught covid19 then 90 will live and 10 will die.
Nor does it mean that if you've been vaccinated you can then not catch covid19. A virus will enter the body just as easy in a vaccinated person as it will in a non-vaccinated person, just that the person's immune response will be greatly different (on average).
Just to finally reiterate that I am no expert on the matter and happy to be corrected on any of the above.
I'm no expert but I think this is the general scope - Different vaccines do things in different ways, but generally once the genome of the virus is known and the shape of the virus is also known and modelled, the development of anti-body inducing proteins (RNA etc) can be designed to prevent the virus from attaching to cells within the lungs and other parts of the body.
The new vaccine will therefore contain newly designed proteins that stimulate the person in to producing an anti-body response, and as such the anti-bodies that the person produces are intended to be such that will attach to the proteins in the vaccine in a similar way that they would attach to the virus. Therefore if the person were to catch the virus, the immune system will identify the shape and deploy the anti-bodies which will be effective against it.
So, true to say that people were not injected with the covid19, there was no need to. Because covid19 had already been sequenced and modelled and a vaccine then designed combat it. (This is the great thing with modern bio-chemistry and the pharmaceutical industry in what it is today).
The efficacy value of say 90% is such that 90% of those vaccinated will develop the intended immune response in producing the intended anti-bodies in readiness for if they were to catch covid19.
It is not as some people think, that if 100 people caught covid19 then 90 will live and 10 will die.
Nor does it mean that if you've been vaccinated you can then not catch covid19. A virus will enter the body just as easy in a vaccinated person as it will in a non-vaccinated person, just that the person's immune response will be greatly different (on average).
Just to finally reiterate that I am no expert on the matter and happy to be corrected on any of the above.
I found this to be a good explanation as to how it works.
He's and audio guy but has a friend who is a doctor.
He's and audio guy but has a friend who is a doctor.
Tim Harford, who does the More Or Less podcast, has another one specifically on Covid and vaccination, worth a listen
https://www.bbc.co.uk/programmes/m000py6s/episodes...
https://www.bbc.co.uk/programmes/m000py6s/episodes...
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