Sure, but your normal immune response applies the same selective pressures and allows order of magnitude more replication prior to that giving the virus orders of magnitude more chances to come up with a mutation to circumvent them. Even without preventing infection entirely vaccination still seems drastically better than the alternative.
It seems like it may be the opposite of what you're saying, though. Vaccinated are just as likely to be infected, but are infected for a shorter time and do tend to get less sick. Natural immunity from a previous infection still reigns supreme, though.
I don't think that's true. Vaccination is still beneficial to infection.
Selection pressure exists, but they will exist whether or not the immune pressure comes from vaccination or infection, so it's preferable to protect first.
Not really, because they can still mount a strong response from the infection. The immune system is a lot more than just antibodies.
Even a weak response to the vaccine can activate bound antibody responses during challenge, which means the immune system is activated much faster and even though there is still infection it is much shorter, leaving less of a chance for the virus to mutate.
well I'd assume that one can also get more immunity thru more vaccine shots and it's a much less risky strategy (aka no virus that can self-replicate) than intentionally exposing oneself to the virus.
Infection itself seems to reduce the risk reliably too. I suspect at a similar rate & more durably, especially considering that the vaccine only generates an immune response based on a single sub-unit of a protein. Versus infections where every protein is presented to the immune system.
I suspect the human body responding to that complete antigen is doing something much more complex & effective than an admittedly genius human invention. Perhaps we'd be wise to consider that even our best efforts are often (in ways we don't even understand) inferior to millions of years of evolution.
Vaccination means you don't need to limit exposure so much, which reduces selection for casual transmissibility. It also means the existing un-mutated virus has far less of an opportunity to "experiment" and mutate further.
The basic argument is that if you are vaccinated, and then contract the virus, the immune system will only produce antibodies for the spike protein in the vaccine, and it will not “learn” how to attack other parts of the virus.
If a new variant has a spike protein different enough, then you will not be in a better situation than an individual with no vaccine and no previous contact with the virus.
In contrast, someone with natural immunity would have the ability to produce a wider range of antibodies that target many different parts of the virus, therefore many more variants would be vulnerable to at least some of the antibodies.
(Caveat: the immune system actually is more complex than that)
There's very little functional difference between being immune to a virus because of previous infection and being immune to a virus because of vaccination. The latter basically co-opts the body's response to the former to generate a lasting adaptive defense.
The original virus and the mutation compete for survival in a host body with a partially effective vaccination.
If you generate only a subset of the typical complement of antibodies that a vaccinated individual does, and are less protected and become infected as a result... then any virus variants that emerge within your body that escape any of your antibodies will have a fitness advantage. In turn, that virus will have an advantage spreading to other vaccinated individuals, too.
It is a low probability event in each individual, but if you generate enough individuals like this and infect them all, it's sure to happen eventually. We can't really estimate what the probability of this happening is, but it's certainly less likely if the efficacy is high and there's less disease circulating.
No, infection is not more protective than vaccination. Vaccination is much more consistent than infection - not least because the vaccine is not packaged with immune suppressing elements.
Selective responses against the vaccine are only selected for if those pressures persist during replication. It's not enough to have that pressure at the very beginning, it needs to persist all the way. This isn't really the case for a vaccine.
In other words, by the time the virus is replicating inside of you, it doesn't really have much pressure to evolve to evade those other facets of vaccine immunity, because doing so would probably hurt it.
The UK variant isn't better at evading the immune system from what we know. It's simply more infectious in general.
Vaccination would not help because it works exactly the same way.
Vaccination certainly helps for the initial response, so people don't get as sick. But after that natural immunity is superior to vaccination.
But it's not true what you say, a mutated virus can still elicit a partial response. So if people are constantly exposed to the new virus they will never get seriously sick.
So here’s my logic but sounds a bit different than yours…
While vaccinated people can be infected, the rate of infection is significantly reduced and therefore fewer opportunities for the virus to mutate.
But if the primary originator of variants are immunocompromised people then this wouldn’t be such a benefit.
Fundamentally, very viral replication has a similar probability of a mutation happening and so therefore (it seems to me) that immunocompromised people are only more likely to generate new variants bc their infections last so much longer. Is this correct?
Sort of. The thing is, while there are already variants out there that impact immune response, it's not like a single mutation is a vaccine escape. It's more like the vaccines go from 95% efficacy to 75% efficacy.
Now, I'm no biologist but I would imagine DNA viruses are easier to vaccinate primarily because they have lower mutation rates than RNA viruses. However, even within RNA viruses, there's differences in mutation rates. Influenza mutates so fast (and is allowed to replicate out-of-control most of the time) to the point that vaccine escape happens within a year or so - that's why you need a new flu shot every year. As far as I'm aware, COVID-19 mutates slower than the flu, so vaccine escape will take longer.
Out of the three COVID-19 vaccines out there, two of them use an mRNA vaccine platform. This isn't because you need to match mRNA viruses with mRNA vaccines, but because it's just an extremely versatile platform to work with. In fact, for Moderna, stopping a worldwide pandemic was just a side project. Their actual goal was to produce custom cancer vaccines tailored to an individual patient's tumors. You can do this because the vaccine is just some genetic material and some nanoparticles to get it into cells. Your body itself makes the actual antigens that your immune system then fights.
So what will ultimately happen in the event of a vaccine escape is that Moderna and Pfizer will tweak their vaccines a little and the FDA will fast-track a new roll-out of the modified shot after Stage 1 testing. They already do this for flu vaccines - it's the only reason why we can even vaccinate against the flu in the first place. And as far as I'm aware, Moderna and Pfizer are both already trialling booster shots. Not so much because they expect a vaccine escape, but because they expect immunity to wane regardless of how fast the virus mutates.
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