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Evaluating necessity of Covid-19 vaccination in previously infected individuals

medrxiv.org

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Re: Evaluating necessity of Covid-19 vaccination in previously infected individuals

#251

Post by johnchristopher »

whoknowswhat11 wrote: post #204
phkahler wrote: post #101

Earlier quoted context omitted.

>> So this study doesn't have enough statistical power to say how vaccines compare to previous infection. Could be better, could be up to 3 times worse within a high confidence interval. Could be. But it would be great if they'd just say having had a confirmed case is equivalent to getting the vaccine because several studies have now shown that to be roughly the case. It's also conventional medical wisdom although it…

No kidding. It's clear to me that protection at some level is provided following infection - which simply makes sense. You'll notice they say - we don't have enough data. Then data is incomplete. Then we can't really say because study was X / Y / Z. They ignore the MASSIVE difference in your chance of being infected if you are unvaccinated and have not been infected vs many other combos. Just treat folks who've been…

I'd like to know the death rate of infected unvaccinated people who get covid again against vaccinated people who get covid and get sick.

Re: Evaluating necessity of Covid-19 vaccination in previously infected individuals

#252

Post by lorenzhs »

TacticalCoder wrote: post #212
tgsovlerkhgsel wrote: post #43

Earlier quoted context omitted.

For the EU certificate, proof of prior infection can be used, although I believe you need a positive PCR test for that, an antibody test is not sufficient.

> ... although I believe you need a positive PCR test for that, an antibody test is not sufficient. Most countries in the EU just relaxed the requirements to travel before the summer vacations. You don't need a PCR test anymore to travel: just an antibody test (at least for Spain / France / Belgium but I take it many others are doing the same). And there's no requirement to be vaccinated. They also raised the age at…

Antigen tests (the rapid test kit, results in ~15 minutes, sample taken from the nose or thread) are not the same as antibody tests (blood test for prior infection, has to go to the lab). You need the former for travel. Afaik, the latter is not accepted as proof of prior infection, you need a positive PCR test from at least 28-ish days ago.

Re: Evaluating necessity of Covid-19 vaccination in previously infected individuals

#253

Post by thombat »

falcor84 wrote: post #244
whizzter wrote: post #241

Earlier quoted context omitted.

Maybe too short, but also Covid-19 isn't really just one disease anymore, but rather a family of strains. Just yesterday the news had an article about how a national level soccer player for Sweden who had been infected previously in the past managed to get infected again and infect parts of the team. The player in question had been infected about a year ago initially (before the British strain was found) and with the…

>...with the British strain now being the main one in Sweden Off topic, but at this stage I find this geographical naming of strains being much more confusing than useful.

Recently greek letters were introduced to remove the geographic stigma [1] , so that would read as "the Alpha strain now being the main one in Sweden"

Besides risking moral overtones ("the British strain? Typical - when they aren't being Hollywood baddies they're busy incubating viruses") it only tagged where a strain was first isolated, not necessarily its geographic origin (not that it actually matters whether the Kent variant actually came from that Home County)

[1] https://www.abc.net.au/news/2021-06-08/covid-19-variants-del...

Re: Evaluating necessity of Covid-19 vaccination in previously infected individuals

#254

Post by johnchristopher »

falcor84 wrote: post #244
whizzter wrote: post #241

Earlier quoted context omitted.

Maybe too short, but also Covid-19 isn't really just one disease anymore, but rather a family of strains. Just yesterday the news had an article about how a national level soccer player for Sweden who had been infected previously in the past managed to get infected again and infect parts of the team. The player in question had been infected about a year ago initially (before the British strain was found) and with the…

>...with the British strain now being the main one in Sweden Off topic, but at this stage I find this geographical naming of strains being much more confusing than useful.

https://www.nature.com/articles/d41586-021-01483-0

> Coronavirus variants get Greek names — but will scientists use them? From Alpha to Omega, the labelling system aims to avoid confusion and stigmatization.

Re: Evaluating necessity of Covid-19 vaccination in previously infected individuals

#255

Post by barney54 »

cbsmith wrote: post #200
phkahler wrote: post #101

Earlier quoted context omitted.

>> So this study doesn't have enough statistical power to say how vaccines compare to previous infection. Could be better, could be up to 3 times worse within a high confidence interval. Could be. But it would be great if they'd just say having had a confirmed case is equivalent to getting the vaccine because several studies have now shown that to be roughly the case. It's also conventional medical wisdom although it…

Unfortunately, we have reason to believe that over time, the immune defenses from COVID-19 infection seem to decline, particularly in older folks. It'd be great if we had some definitive data on secondary infection rates, but until a lot more people get infected, we just won't have it.

What is the evidence that “we have reason to believe that over time, immune defenses from COVID-19 infection seems to decline”?

Re: Evaluating necessity of Covid-19 vaccination in previously infected individuals

#256

Post by leoedin »

f6v wrote: post #229
daenz wrote: post #128

Why is it that so many people seem to be biased against evidence that our immune systems do a pretty good job? It's as if they want the vaccine to be the only thing that helps stop COVID.

> It's as if they want the vaccine to be the only thing that helps stop COVID Our immune system didn't evolve to cope with living in incredibly tight spaces surrounded by millions of people. Our immune system also isn't good at dealing with infections as we age: it's simply unnatural to survive past 70. We need to keep vaccinating, to create a collective immunity that protects the vulnerable.

Vaccinating is literally training the immune system to look for a specific protein and treat it as a threat.

When your immune system learns how to fight off a virus, it does it by creating antibodies for a specific protein - treating that protein as a threat.

They're effectively the same thing. The only thing the vaccine does differently is it doesn't exponentially reproduce in your cells.

So anyone who survived Covid by definition has an immune system which can recognise the virus and attack it. Otherwise they wouldn't have survived.

Re: Evaluating necessity of Covid-19 vaccination in previously infected individuals

#257

Post by rolph »

f6v wrote: post #247
rolph wrote: post #25

the problem with live covid as the antigenic character is of course the mortality, and the morbidity risk. there is also the instability of the spike protien in its natural form. when spike is cloven at it cleavage site it changes conformation, thus there are two faces available to the immune system; the default state, the cloven prefusion state. This makes a Naturally aquired immunity biased toward opsonizing antbod…

> the vaccine version of spike has been stabilized so as to remain in the default state resulting in a bias toward neutralizing antibodies. I'm not strong in molecular immunology. Does that also hold for the mRNA vaccines? Or only those that ship the spike protein itself?

yes this is the case for the vaccines, and any synthetic protien based vaccine that is to come. there is a manner of inserting a couple of extra amino acids at a crucial location that will prevent the change of state when cleavage is activated. This leaves it "open" to binding at points required for cellular entry.

this took the better part of 12 years to understand the virus to the point that we knew how to stabilize tthe spike.

Re: Evaluating necessity of Covid-19 vaccination in previously infected individuals

#258

Post by lorenzhs »

nradov wrote: post #188
jquery wrote: post #167

Earlier quoted context omitted.

Antibody test is not proof of prior infection.

What do you mean by that? The false positive rate is extremely low. It's as close to proof as we're going to get.

What they might have meant is that many countries accept a positive PCR from >= 4 weeks ago as proof of prior infection (and therefore, presumed immunity), but not an antibody test. I'm not familiar with the error rates of the latter, but for the purposes of travel a positive antibody test is rather useless.

Where I live, you need to meet one of three conditions for things like indoor dining:

- proof of a full course of vaccination (2 weeks after the final shot)

- proof of prior infection - antibody test not accepted, only positive PCR between 1 and 6 months ago

- proof of an antigen test (rapid test) that's at most 24h old

Re: Evaluating necessity of Covid-19 vaccination in previously infected individuals

#259

Post by Pyramus »

Izkata wrote: post #191
phkahler wrote: post #103

Earlier quoted context omitted.

>> They also mentioned 0 infections in fully vaccinated which is odd as other countries are seeing a number of infections in their vaccinated front line workers. No, they had infections in the vaccinated. They had 0 infections in the previously infected, although another poster pointed out that the vaccinated (but never infected) group is much larger than the unvaccinated but previously exposed. Frankly since the vac…

Immunity from infection does more than the spike protein, so it ought to be more robust against variants, even if one does show up that changes the spike protein enough to escape vaccines.

My understanding is that it's not clear at all with respect to variants, hence this study.

The spike protein has been picked for the reason that it's unlikely to change.

Re: Evaluating necessity of Covid-19 vaccination in previously infected individuals

#260

Post by Reason077 »

whizzter wrote: post #241
qrybam wrote: post #235

Earlier quoted context omitted.

That’s interesting. Maybe the duration of the trial was too short or sample size too small, because I know two people personally who were re-infected pre vaccination.

Maybe too short, but also Covid-19 isn't really just one disease anymore, but rather a family of strains. Just yesterday the news had an article about how a national level soccer player for Sweden who had been infected previously in the past managed to get infected again and infect parts of the team. The player in question had been infected about a year ago initially (before the British strain was found) and with the…

> "I don't think it's a far fetch to say that re-infections of a different strain is actually quite likely once a certain amount of time has passed."

Based on my own personal experience (see my other post in this thread), I agree.

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