Question for Vaccine Experts

BFC_BFC_BFC

BFC_BFC_BFC

Well-known member
If a vaccine is 70% effective, does that mean that 70% of people are 100% protected by the vaccine or that 100% of the people are 70% protected?
 
I thought it meant that compared to a control group where nobody had the vaccine, by the time a certain number of people in that control group had hit a set control figure for infections, then the group who had had the vaccine were totaled up, and it was the percentage that didn't catch it from that vaccinated group over the same period of time as the control group.
 
Recidivist3 said:
www.theguardian.com

Behind the numbers: what does it mean if a Covid vaccine has ‘90% efficacy’? | David Spiegelhalter

Confusion surrounds the vaccines’ effectiveness. The leading Cambridge professor clarifies the data behind the trials
www.theguardian.com www.theguardian.com
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Unfortunately that doesn't answer the question... It just tells me what I already know (i.e. what the overall combined 'population' immunity is)... I'm more interested in understanding how that would break down on an individual by individual basis. So in essence is the vaccine completely useless in 30% of people and 100% effective in the other 70%, is it more like shades of grey (i.e. some people are only 10% protected, others 40%, 50, 60% etc..)..
 
BFC_BFC_BFC said:
If a vaccine is 70% effective, does that mean that 70% of people are 100% protected by the vaccine or that 100% of the people are 70% protected?
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It's the same thing.

You either have a 7 in 10 chance of not getting it, or a 7 in 10 chance of not getting it. There's virtually no way of calculating if someone is individually 100% protected as there's no correlation between separate exposures to the virus.
 
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Lytham_fy8 said:
It's the same thing.

You either have a 7 in 10 chance of not getting it, or a 7 in 10 chance of not getting it. There's virtually no way of calculating if someone is individually 100% protected as there's no correlation between separate exposures to the virus.
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I understand what you are saying, but it isn't the same thing at all...

If (for example) 3 individuals are completely unprotected and 7 individuals 100% protected, then that offers significantly better protection than 10 individuals who are 70% protected.

The reason being that if you are 100% protected, then your risk of contracting the disease would not change with your level of exposure, whereas a 70% protected individual would eventually (due to probablility) contract the virus, if exposed to it enough.
 
BFC_BFC_BFC said:
I understand what you are saying, but it isn't the same thing at all...

If (for example) 3 individuals are completely unprotected and 7 individuals 100% protected, then that offers significantly better protection than 10 individuals who are 70% protected.

The reason being that if you are 100% protected, then your risk of contracting the disease would not change with your level of exposure, whereas a 70% protected individual would eventually (due to probablility) contract the virus, if exposed to it enough.
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In reality though it is the same thing, the chances of an individual avoiding avoiding illness is 70% as 100% protection is a hypothetical unknown.

So to answer your original question, 100% are 70% protected.
 
BFC_BFC_BFC said:
I understand what you are saying, but it isn't the same thing at all...

If (for example) 3 individuals are completely unprotected and 7 individuals 100% protected, then that offers significantly better protection than 10 individuals who are 70% protected.

The reason being that if you are 100% protected, then your risk of contracting the disease would not change with your level of exposure, whereas a 70% protected individual would eventually (due to probablility) contract the virus, if exposed to it enough.
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I don't think there is an answer to that question though it appears that most (if not all) people benefit from vaccination and those that catch Covid-19 after being vaccinated have less severe illness than if they have been unvaccinated.

If you catch Covid-19 whilst being vaccinated then it is probably due to a combination of factors such as your individual response to the vaccine, the effectiveness of your own auto-immune system, your exposure to Covid-19 (time and extent of exposure), etc.
 
Lytham_fy8 said:
In reality though it is the same thing, the chances of an individual avoiding avoiding illness is 70% as 100% protection is a hypothetical unknown.

So to answer your original question, 100% are 70% protected.
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It's not the same thing in reality or in practice, which is the reason I asked the question. I'm not trying to understand the population based risk of catching Covid, I'm interested to understand how vaccines themselves work at an individual level .... i.e. is someone simply immune or not immune to a particular virus is everyone (instead) partially immune. I understand what you are saying about 100% protection being a hypothetical unknown, but in terms of "How a typical vaccine would work" I'd have assumed there was an answer...

So it sounds like the answer is... 'You don't know'🤣, which is great.. well not that great, because you were my only hope


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A quote from a Guardian article albeit using 90% as the example.
"Vaccine efficacy is the relative reduction in the risk: whatever your risk was before, it is reduced by 90% if you get vaccinated. There is a lot of confusion about this number: it does not mean there is a 10% chance of getting Covid-19 if vaccinated – that chance will be massively lower than 10%.
Researchers estimate efficacy by comparing numbers of new cases in vaccinated and unvaccinated people, best done through a “randomised control trial”. All volunteers receive an injection but, at random, either the actual vaccine or a placebo.They don’t know which they are getting."
 
BFC_BFC_BFC said:
It's not the same thing in reality or in practice, which is the reason I asked the question. I'm not trying to understand the population based risk of catching Covid, I'm interested to understand how vaccines themselves work at an individual level .... i.e. is someone simply immune or not immune to a particular virus is everyone (instead) partially immune.
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My best guess is it's a continuum depending upon the individuals physiology, the vast majority will have some protection, some will be almost completely immune, others maybe only 50% reduction in infction chance, some may have very little immunity at all, the 70% (or whatever) is the average for the community as a whole.

This is why you see different efficacy figures for infection, hospitalisation and death, even if you catch the virus post vaccination you still have some protection so you body can fight it off more easily.
 
poolseasider said:
Just found out a mate has Covid(for the second time) and has had two jabs. 😳
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I've come across two people the same. The pharmaceutical companies are rubbing their hands, must be making a bob or two. What I can't fathom this is a corona virus just like a cold is. We were always told there isn't a cure for a cold....
 
Lost Seasider said:
My best guess is it's a continuum depending upon the individuals physiology, the vast majority will have some protection, some will be almost completely immune, others maybe only 50% reduction in infction chance, some may have very little immunity at all, the 70% (or whatever) is the average for the community as a whole.

This is why you see different efficacy figures for infection, hospitalisation and death, even if you catch the virus post vaccination you still have some protection so you body can fight it off more easily.
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That would have been my best guess too and it's kind of borne out by potential variations in efficacy by Age Range..... As Lytrham says, on a 'global' basis it doesn't really make any difference (well not at least if you are talking about a cut off for herd immunity being reached for example), but it might matter when significant levels of virus are still circulating.

I was kind of looking at it from a personal 'theoretical perspective' and thinking along the lines of if I had been fully vaccinated and then subsequently exposed to the virus and come out of that situation without being infected, did that mean I was simply immune and really didn't need to worry OR was I at an equal 70% risk on each occasion that I was similarly exposed... (BTW, when I say exposed, I mean being in very close contact, whereby you would be certain to have caught the virus, as opposed to the kind of Covid 19 App style of 'exposed')
 
poolseasider said:
Just found out a mate has Covid(for the second time) and has had two jabs. 😳
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Shandypants said:
I've come across two people the same. The pharmaceutical companies are rubbing their hands, must be making a bob or two. What I can't fathom this is a corona virus just like a cold is. We were always told there isn't a cure for a cold....
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Tested Positive and Asymptomatic, Tested Positive and Symptomatic or Tested Positive and Extremely Ill?
 
BFC_BFC_BFC said:
Tested Positive and Asymptomatic, Tested Positive and Symptomatic or Tested Positive and Extremely Ill?
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One was ill in bed for 3 days in her 30s the other tested positive a week after 2nd jab. In his 50s fairly rough for a few days. Obs neither hospitalised but if this thing is here to stay who wants to keep catching that every six months.
 
A short while ago the government were telling us that a significant number of people, I think it was 1 in 3, can have covid and not be aware!
So if we accept that 33% of people wouldn't be ill anyway does that alter the figures for vaccine effectiveness when it comes to protecting you from serious illness?
I find it all very confusing!!
 
Shandypants said:
One was ill in bed for 3 days in her 30s the other tested positive a week after 2nd jab. In his 50s fairly rough for a few days. Obs neither hospitalised but if this thing is here to stay who wants to keep catching that every six months.
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Fully immunity for the 2nd Jab takes 15+ days by all accounts, so at least one of the two had only 'technically' had one jab on that basis. I suppose we have to hope that the thing dampens down to the same level as other seasonal common cold type coronaviruses.... I can't see it continuing as is for too much longer.
 
BFC_BFC_BFC said:
Fully immunity for the 2nd Jab takes 15+ days by all accounts, so at least one of the two had only 'technically' had one jab on that basis. I suppose we have to hope that the thing dampens down to the same level as other seasonal common cold type coronaviruses.... I can't see it continuing as is for too much longer.
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Maybe but Westminster Council don't seem overly confident

Temporary Body Storage Service [Tender Notice]

The Authority seeks to procure a framework agreement for temporary body storage in the event of an e... A Tender Notice by Westminster City Council. Value £6M.
www.bidstats.uk www.bidstats.uk
 
I'm no expert but I thought the way it works is, you can still catch it but it won't be anything like as bad and you may well show no symptoms at all? Hence the need to keep up the precautions to not pass it on to others who might fare less well?
 
Shandypants said:
Maybe but Westminster Council don't seem overly confident

Temporary Body Storage Service [Tender Notice]

The Authority seeks to procure a framework agreement for temporary body storage in the event of an e... A Tender Notice by Westminster City Council. Value £6M.
www.bidstats.uk www.bidstats.uk
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A framework is not an actual purchase, it's simply a mechanism that would enable a Government Body to quickly make a purchase in line with legal requirements, in the event that it was required. I'd imagine that this will be common practice from hereonin as part of future pandemic planning.... There's obviously been loads of criticism for the Goverment bypassing normal procurement process, due to Covid pressure, thgis type of advance framework means that they can expediate the procurement process legally.
 
BFC_BFC_BFC said:
A framework is not an actual purchase, it's simply a mechanism that would enable a Government Body to quickly make a purchase in line with legal requirements, in the event that it was required. I'd imagine that this will be common practice from hereonin as part of future pandemic planning.... There's obviously been loads of criticism for the Goverment bypassing normal procurement process, due to Covid pressure, thgis type of advance framework means that they can expediate the procurement process legally.
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I'm aware what it is. I've got bad vibes about how successful the vaccine will be, they know more than you and I and if the picture was positive I doubt they'd bother
 
Shandypants said:
I'm aware what it is. I've got bad vibes about how successful the vaccine will be, they know more than you and I and if the picture was positive I doubt they'd bother
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Like I say, I suspect it's more about getting the right practices in moving forward as opposed to any expectation regarding the virus. A simple case of putting measures in place so they don't get caught with their pants down again. 👍
 
BFC_BFC_BFC said:
Like I say, I suspect it's more about getting the right practices in moving forward as opposed to any expectation regarding the virus. A simple case of putting measures in place so they don't get caught with their pants down again. 👍
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I was hoping to get away without posting a Covid stats update today. Well that isn't going to happen. Here's the overall picture (1) https://t.co/PiDX7mML2C

Interesting but slightly worrying thread
 
BFC_BFC_BFC said:
It's not the same thing in reality or in practice, which is the reason I asked the question. I'm not trying to understand the population based risk of catching Covid, I'm interested to understand how vaccines themselves work at an individual level .... i.e. is someone simply immune or not immune to a particular virus is everyone (instead) partially immune. I understand what you are saying about 100% protection being a hypothetical unknown, but in terms of "How a typical vaccine would work" I'd have assumed there was an answer...

So it sounds like the answer is... 'You don't know'🤣, which is great.. well not that great, because you were my only hope


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No, the answer is 'there is no answer to your question'. There is no such thing as an individual being 100% immune to a virus.
 
Lytham_fy8 said:
No, the answer is 'there is no answer to your question'. There is no such thing as an individual being 100% immune to a virus.
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No such thing ?

Do you mean we haven't the means to determine 100% immunity as an absolute fact or that it has been established that it is not possible for an individual to achieve 100% immunity from a virus?

I mean I'd imagine there is an answer to my question, though I appreciate you might not have it....

I could, for example, envisage a fairly straightforward way to determine whether 100% immunity had been achieved in one individual vs another, to a pretty high degree of certainty and also how you might therefore answer the question in the O/P...

I'm not really sure that "I don't know, so it doesn't exist" is adequate....
 
it is not just the percentage chance of getting the virus that is important but it is also the chance of being seriously ill, hospitalised and dying. The latter 3 are drastically reduced.
 
BFC_BFC_BFC said:
No such thing ?

Do you mean we haven't the means to determine 100% immunity as an absolute fact or that it has been established that it is not possible for an individual to achieve 100% immunity from a virus?

I mean I'd imagine there is an answer to my question, though I appreciate you might not have it....

I could, for example, envisage a fairly straightforward way to determine whether 100% immunity had been achieved in one individual vs another, to a pretty high degree of certainty and also how you might therefore answer the question in the O/P...

I'm not really sure that "I don't know, so it doesn't exist" is adequate....
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'I could, for example, envisage a fairly straightforward way to determine whether 100% immunity had been achieved in one individual vs another, to a pretty high degree of certainty and also how you might therefore answer the question in the O/P...'

No, you cannot guarantee 100% immunity, you can estimate a percentage in comparison to another group, certainly not on a 1:1 individual basis as there's a possibility of far too many mitigating factors, was one individuals immune system compromised at the time for example? Also if you somehow manage to test for 100% immunity, are you going to being them in on every 48 hours for a few years to test again because a) no one knows how long immunity lasts and b) your immune system can change from day to day.

The percentage figures quoted are taken from control groups, that's the answer to your original question, no you're not '70% immune', that's not achievable data, it's frankly ridiculous to think it is. If you don't believe me ask a virologist where the figure comes from, or a data analyst.

It's only a conversation, you don't have to be a snarky little cnut just because you're not getting the answer you want.
 
Lytham_fy8 said:
'I could, for example, envisage a fairly straightforward way to determine whether 100% immunity had been achieved in one individual vs another, to a pretty high degree of certainty and also how you might therefore answer the question in the O/P...'

No, you cannot guarantee 100% immunity, you can estimate a percentage in comparison to another group, certainly not on a 1:1 individual basis as there's a possibility of far too many mitigating factors, was one individuals immune system compromised at the time for example? Also if you somehow manage to test for 100% immunity, are you going to being them in on every 48 hours for a few years to test again because a) no one knows how long immunity lasts and b) your immune system can change from day to day.

The percentage figures quoted are taken from control groups, that's the answer to your original question, no you're not '70% immune', that's not achievable data, it's frankly ridiculous to think it is. If you don't believe me ask a virologist where the figure comes from, or a data analyst.

It's only a conversation, you don't have to be a snarky little cnut just because you're not getting the answer you want.
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Eh Dear, you aren't half developing into a grumpy bastard in your latter years.....

I'm not trying to be snarky, just simply trying to develop your answer and inject a bit of condescending humour...As you say it's a conversation, I'm not obliged to accept your first answer and just shut up am I?

I mean Measles is a virus, is it not and according to the stats it offers 'immunity' to something like 99.7% of individuals... So that appears to be complete immunity.

I'm simply trying to understand the principle of how vaccine effectiveness works as opposed to actually establishing whether 100% efficacy can be empirically proven and even if it is whether that might wain over time...I fully understand how the statistics for Covid 19, during the trials have been collated and the generakl principle, but that's not what I'm asking here... I'd have never bothered asking the question if I just wanted the basic answer (that the vaccinated group has 70% less virus than the control group)...

I mean presumably you could undertake animal trials where individual animals were regularly and repeatedly exposed to a virus for example.

As I have previously said the idea of being 70% immune to my mind doesn't make much sense...in fact you may as well say you aren't immune at all...
 
This isn't my argument but just popped back on to see if you had had a reply that at least 70% satisfied you. 😉
However with the greatest respect, if you're not just playing with posters for the fun of it, you really are over-thinking this.
The stat is simple. It just tells you that having a vaccine reduces the chances of you catching the virus.
Back to the football, just waiting for the next penalty. The chances of another in the France match are about 85% 😁
 
Insider said:
This isn't my argument but just popped back on to see if you had had a reply that at least 70% satisfied you. 😉
However with the greatest respect, if you're not just playing with posters for the fun of it, you really are over-thinking this.
The stat is simple. It just tells you that having a vaccine reduces the chances of you catching the virus.
Back to the football, just waiting for the next penalty. The chances of another in the France match are about 85% 😁
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Thanks Insider, but you answered a different question to the one I'm asking 👍

I also appreciate what you are saying, but I'm not overthinking it at all, you are perhaps just happy to 'underthink' it, which is fine. I have a good reason for wanting to understand this properly.

There's a world of difference between the two scenarios I outlined in my O/P...
 
BFC_BFC_BFC said:
Thanks Insider, but you answered a different question to the one I'm asking 👍

I also appreciate what you are saying, but I'm not overthinking it at all, you are perhaps just happy to 'underthink' it, which is fine. I have a good reason for wanting to understand this properly.

There's a world of difference between the two scenarios I outlined in my O/P...
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I think then that you are looking for an answer from a stat that doesn't address your question.
There's probably loads of data been collected to give you an answer but it's just not been published yet.
 
Insider said:
I think then that you are looking for an answer from a stat that doesn't address your question.
There's probably loads of data been collected to give you an answer but it's just not been published yet.
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I was really looking to see if there was a straightforward 'vaccine principle' that would have offered the answer to the question.

I think it's probably generally accepted (for example) that in the case of diseases like Chickenpox, that most people will have it once and then they are completely immune and will never get the disease again. However a small number of people will not develop that immunity and will therefore be ssceptible to getting it again. In that case most people develop 100% immunity and could therefore happily sit in a room full of Chickenpox infected people, safe in the knowledge that they would have no chance of contracting the disease.

I suspect Covid probably differs insomuch as the vaccines probably don't really offer total immunity to anyone at all, but instead offer a varying degree of alleviation of symptoms for those who happen to contract the disease.
 
BFC_BFC_BFC said:
I was kind of looking at it from a personal 'theoretical perspective' and thinking along the lines of if I had been fully vaccinated and then subsequently exposed to the virus and come out of that situation without being infected, did that mean I was simply immune and really didn't need to worry OR was I at an equal 70% risk on each occasion that I was similarly exposed... (BTW, when I say exposed, I mean being in very close contact, whereby you would be certain to have caught the virus, as opposed to the kind of Covid 19 App style of 'exposed')
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I think the way it works (or at least a large part) is that none of us are immune from contracting the virus, it can still enter your body and start to replicate at which point you're infected.

The vaccine primes the immune system to respond to the virus more quickly than it would naturally, in some people the response is so quick that you'll never know you've got the virus and will eliminate it very quickly, and before you can infect others, in others the response might be slower in which case they might test positive, might be infectious and display symptoms, although usually less serious than otherwise might be the case.

It may also depend upon the initial viral load, which is to say how much of the virus you are exposed to in the first place, 8 hours in bed with an infected partner implies a much greater exposure than a shorter and more distanced interaction of whatever nature, and this could have an effect on the course of the infection.

Other factors may also be at play, protection might wane over time, infection with other diseases might affect the response, certain drugs or lifestyle factors may have effects.

Or I could be completely wrong.
 
Lost Seasider said:
I think the way it works (or at least a large part) is that none of us are immune from contracting the virus, it can still enter your body and start to replicate at which point you're infected.

The vaccine primes the immune system to respond to the virus more quickly than it would naturally, in some people the response is so quick that you'll never know you've got the virus and will eliminate it very quickly, and before you can infect others, in others the response might be slower in which case they might test positive, might be infectious and display symptoms, although usually less serious than otherwise might be the case.

It may also depend upon the initial viral load, which is to say how much of the virus you are exposed to in the first place, 8 hours in bed with an infected partner implies a much greater exposure than a shorter and more distanced interaction of whatever nature, and this could have an effect on the course of the infection.

Other factors may also be at play, protection might wane over time, infection with other diseases might affect the response, certain drugs or lifestyle factors may have effects.

Or I could be completely wrong.
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That seems logical to me tbh…

It would explain why vaccine is less effective against more transmissible strains of the virus.

So instead of the Measles / Chicken Pox situation, where it seems you are either immune or you’re not, Covid is simply a case of your immune system being ‘perked up’ to varying degrees of effectiveness. Not that dissimilar to how our immune systems (without the vaccine) have responded really…
 
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