What’s the science behind allowing fully vaccinated people more freedoms?

[SparklesandGold]

I’m fully vaccinated and I do think if people can get vaccinated then they absolutely should but obviously if someone decides not to then that’s their own business.

I don’t agree with this nonsense of excluding unvaccinated people from doing certain things.

Is there any scientific evidence to back that up? Does being fully vaccinated actually reduce someone spreading the virus if they have it?

No, you're drawing an inference there that doesn't exist. These studies do not treat all unvaccinated people as if they are not immune. They simply report on the relative infection rates and risk of the vaccinated and unvaccinated groups, with all the variation in immunity that lie within them.

Ok. I’m simply trying to point out that, as the data stands, it is not able to show whether an unvaccinated previously infected person is any more of a transmission risk than a vaccinated person because all unvaccinated are bundled together, regardless of their previous infection status.

It's already simpler if only because vaccination data exists; immunity data doesn't.

Proof of a positive test result within a certain time period is considered proof of infection. Studies have shown that infection results in durable immunity for the majority. So people who are infected during a certain time period (usually 6 months, Ireland have just been advised that they can increase to 9 months) have presumptive immunity.

We should probably also consider using positive antibody tests as proof of immunity for people who were infected before we started mass testing. I think the information is there (and the science to back it up) we just need to decide to use it.

Ok. I’m simply trying to point out that, as the data stands, it is not able to show whether an unvaccinated previously infected person is any more of a transmission risk than a vaccinated person because all unvaccinated are bundled together, regardless of their previous infection status.

Yes, but the data I've referred to, and the studies it informs, aren't claiming to show that. It's not looking at individual relative risk at all. It's simply comparing two groups. The PP I was responding to (and the OP, somehow we're still on topic) was questioning the scientific basis of treating vaccinated and unvaccinated groups differently. This data provides that rationale - the groups present different levels of risk.

I get what you're trying to point out. It's just completely irrelevant to any point I made, and the data I used to support it, which is why I'm a bit frustrated.

certain time period is considered proof of infection. Studies have shown that infection results in durable immunity for the majority. So people who are infected during a certain time period (usually 6 months, Ireland have just been advised that they can increase to 9 months) have presumptive immunity.

OK, as proof of previous (mostly) symptomatic infection rather than immunity - it still adds a layer of complexity in administration. Again, I'm not advocating for either.

I do see what you’re saying and I’m not taking issue with you personally. Sorry if it has come across like that!

I do take issue with the data that they’re using to prove this rationale. They really shouldn’t be considering previously infected and not previously infected in the same group for unvaccinated people. Vaccinated vs unvaccinated is far too simplistic.

Proof of previous infection is already used for ‘green cards’ in other countries. It really shouldn’t be beyond us to include it here too.

I do take issue with the data that they’re using to prove this rationale. They really shouldn’t be considering previously infected and not previously infected in the same group for unvaccinated people. Vaccinated vs unvaccinated is far too simplistic.

To be honest, once you look at that data and know that there is a level of immunity in the unvaccinated group, it just makes the vaccine performance look even more impressive.

There will never be a perfect grouping for public policymaking. It's all a series of fudges, some of which will be more palatable to some people, some will be more palatable to others.

To be honest, once you look at that data and know that there is a level of immunity in the unvaccinated group, it just makes the vaccine performance look even more impressive.

Yes - I think this is a point that's often missed.

To be honest, once you look at that data and know that there is a level of immunity in the unvaccinated group, it just makes the vaccine performance look even more impressive.

Why? As we’ve already discussed, we don’t know what proportion of people in that unvaccinated group were previously infected or not.

Not that the vaccine isn’t doing a good job. (Before someone jumps on me )

[quote bumbleymummy]@3womeninaboat herd immunity after infection is actually a thing. It just wasn’t advised for coronavirus because it would have resulted in too many hospitalisations/deaths in the most vulnerable groups. Immunity that comes from vaccination or previous infection all contributes to herd immunity. Although apparently it’s not actually going to be possible to achieve herd immunity with delta anyway.[/quote]
This is where masks could help isn't it? Allowing people to catch Covid, but with a lower viral load and therefore less serious.

@bumbleymummy

To be honest, once you look at that data and know that there is a level of immunity in the unvaccinated group, it just makes the vaccine performance look even more impressive.

Why? As we’ve already discussed, we don’t know what proportion of people in that unvaccinated group were previously infected or not.

Not that the vaccine isn’t doing a good job. (Before someone jumps on me )

Because when you look at vaccine efficacy it is assumed from a point of no immunity in the unvaccinated group.

Vaccine efficacy at 60% when compared against a group with partial immunity means it's doing an even better job than vaccine efficacy at 60% when compared against a group with no immunity.

Why? As we’ve already discussed, we don’t know what proportion of people in that unvaccinated group were previously infected or not.

Actually, there is some data on this that shows there is a level of immunity among the unvaccinated. We don't know the exact proportion, but we know that it's there - and this is backed up by the ONS antibody data (93.6% of adults with antibodies in w/c 12 July; with around 85% of adults with a first dose only a week prior, I'm being generous.)

Now, the REACT-1 numbers I quoted above include under-18s, who aren't captured in the ONS antibody data. But we know from the separate ONS work that there are antibody levels of around 15% in primary and secondary school kids.

Separately, REACT-2 looks at antibody levels in adults. In their May round, they found prevalence of antibodies in their unvaccinated group was around 13.6%.

It's therefore very difficult to argue that there isn't a level of immunity in the unvaccinated group, though of course we know that the presence of antibodies alone doesn't necessarily prevent infection.

So you're not comparing vaccine performance, based on the level of infection in the vaccinated group, against levels of infection in a totally immunologically naive control group. There's already a level of immunity in the control group, which will reduce the rate of infection in that group. Hence my comment about the impressiveness of the vaccine performance - as it's not being measured against a true control.

It will be interesting to see how the vaccines perform in countries that don't have significant pre-existing infection levels and therefore a small degree of community immunity.

Should note that the REACT-2 figure I mentioned was the unweighted figure - weighted to population it's a little higher.

Ah, @ollyollyoxenfree did it with around 90% fewer words!

@JassyRadlett

Ah, *@ollyollyoxenfree* did it with around 90% fewer words!

I liked your detailed explanation @JassyRadlett

It's therefore very difficult to argue that there isn't a level of immunity in the unvaccinated group

I’m not arguing that though. I know there is some level of immunity among the unvaccinated - that’s what we’ve been taking about. My point was that we don’t know how many people/what percentage exactly because they’re all just bundled together. Yes, it could be 10-15% or it could be 0-5%. We just don’t know.

I would like to see studies investigating transmission between vaccinated and previously infected people.

(Thank you for taking the time to write out the above btw.)

My point was that we don’t know how many people/what percentage exactly because they’re all just bundled together. Yes, it could be 10-15% or it could be 0-5%. We just don’t know.

We don’t know the exact percentage of anything except vaccinations, positive tests, hospitalisations and deaths.

On what are you basing the ‘we just don’t know’, though? We’ve got some decent datasets that have been gathered over long time periods so we’ve a decent level of confidence that there aren’t sudden aberrations.

You keep saying they’re ‘all bundled together’. REACT-2 unbundled into those with antibodies, and those without in the unvaccinated group. It also has LOADS of other data so is worth a good read.

The idea that it is as low as 0-5% would support the idea that vaccination status is a decent proxy for immunity status in public health terms, though. However I’ve seen absolutely nothing that supports the idea that it’s that low.

And regardless, my original point still stands. The control group for vaccine effectiveness isn’t completely immunologically naive, and therefore the vaccine performance is more impressive than it might first appear.

Will check out REACT, thanks.

I suppose we also need to factor in that a certain percentage of vaccinated people were also previously infected.

I suppose we also need to factor in that a certain percentage of vaccinated people were also previously infected.

In what way? We haven't gone down a route in this country of only single vaccines for previously infected people. The research on single v double dose for the previous infected simply seems to conclude that the second shot doesn't do a lot.

I would like to see studies investigating transmission between vaccinated and previously infected people.

I'm curious why you think this would be useful?

@JassyRadlett

I suppose we also need to factor in that a certain percentage of vaccinated people were also previously infected.

In what way? We haven't gone down a route in this country of only single vaccines for previously infected people. The research on single v double dose for the previous infected simply seems to conclude that the second shot doesn't do a lot.

I would like to see studies investigating transmission between vaccinated and previously infected people.

I'm curious why you think this would be useful?

In relation to this:

The control group for vaccine effectiveness isn’t completely immunologically naive, and therefore the vaccine performance is more impressive than it might first appear.

The vaccine group may not be immunologically naive either.

Wrt comparing transmission between vaccinated and unvaccinated previously infected people - if transmission rates are similar then previously infected people could be treated the same as vaccinated people -as discussed above.

The vaccine group may not be immunologically naive either.

Well we know they’re not, 100% of them, because they’ve had the vaccine which appears to confer immunity at least equal to virus-acquired. I take the point you’re trying to make and I’ll give it some deeper thought but I’m not convinced it’s an equal effect.

Wrt comparing transmission between vaccinated and unvaccinated previously infected people - if transmission rates are similar then previously infected people could be treated the same as vaccinated people -as discussed above.

I mean tbh you don’t need it to be between two groups, you just want it the same as from the vaccinated group. Because transmission chains won’t only be at the place you’d need the passport for, they’d also be ongoing.

But that data is pretty negligible for delta even in the vaccinated group. From existing info on delta ‘much less likely to get it’ is the primary driver, imagine the same data would be considered in a push for immunity passports.

@JassyRadlett immunologically naive pre-vaccine :)

Sorry, my transmission part was worded badly - when I said ‘between vaccinated and previously infected groups’ I meant comparing transmission from vaccinated people to transmission from previously infected people - a comparison of the levels of transmission from the two. Hope that clears it up a bit!

Yes, either/both metrics could be used - transmission and/or ‘less likely to get’. If they’re similar for vaccinated and previously infected people then previously infected people should be treated the same wrt passports etc.

There isn't any science, it's just trying to force people to be vaccinated.

Especially as Austria and Croatia have now decided that the protection only lasts for 270 days.

Ugh, that transmission part reads badly too 🙄 I don’t mean looking at transmission from one group to the other. I mean looking at transmission from one group snd comparing it to transmission from the other group to see whether there is any difference in transmission from either group.

I know three double vacc people who currently have it, who have also decided it’s no big deal and went and did a big shop as a group yesterday maskless because they are double vacc so what’s the problem.

I think there might be quite a few people like that so seems this whole double vacc people are safe will be what leads to higher figures.