My mental model of this (and I'm not a medical expert) is that (a) for a given amount of spike protein, the immune response is similar, whether the protein originates from the vaccine or the actual virus, but (b) since the vaccine is lacking the actual health threatening properties of the virus, you can expose people to massive doses of it without incurring much risk.
It depends how different the response to the vaccine vs the virus is. e.g. the vaccine immune response is based on the spike, while the virus could trigger an immune response based on some detail on the virus, but not the spike
That was my thought as well. Natural immune response should have more vectors of attack since all of the virus proteins are available to make antibodies for.
As another comment mentioned though, the spike protein is unlikely to change much, and if it did, the virus would loose a major weapon in infecting people. So the vaccine is probably as effective as natural immunity in practice.
Consider the magnitude of the immune response. In someone with pre-existing immunity the virus may replicate relatively little before being killed. Compare this to getting the vaccine, where your body will be flooded with spike protein whether you have previous immunity or not.
One vaccine doesn't even trigger the same immune response in different people, so it is not entirely clear to me what you mean.
The basic principle of a vaccine is that it contains proteins that are the same as (or similar to) some of the protein building blocks of the actual virus. Your body learns an immune response to these proteins, which it can reactivate when it encounters the real thing.
Many potential vaccines target the same spike proteins on the outside of the virus. I guess you could say those produce "the same immune response" in that sense.
From my understanding, there are two main reasons.
1) The two spaced exposures. Repeated spaced exposures build a significantly stronger response.
2) Isolation of the spike protein. Just like ML might pick up on a correlated part of the image while learning to recognize things (many examples, no good links), your immune system may learn to react to different parts of the virus. The spike protein is the most unchanging part, and all the vaccine will teach your body to attack.
Mutations in spike proteins don’t completely change it’s shape so they render a percentage of antibodies infective vs that specific strain. A boosted immune response can therefore be less efficient but still useful.
To simplify, Vaccines provide long term protection because the immune system builds infrastructure to rapidly create antibodies after infection cutting days off of the immune response. That’s huge because the virus has less time to replicate in your body. Vaccines use multiple injections to increase how much infrastructure is built and the number of types of antibodies being produced. Also this infrastructure decays over time if you never see the strain again.
However, in the short term your body reacts like it’s infected actually flooding the body with the appropriate antibodies. This isn’t sustainable but can crush most infections before they go anywhere. Kind of a bonus turbo mode which can be really helpful if your say going to treat people infected with the disease.
A natural immune response will contain antibodies that will attack all parts of the virus, putting selection pressure towards changing the shell of the virus which can be done without compromising the functionality. By only providing the spike protein via a vaccine, you ensure that the selection pressure is against the key functionality of the virus. Changes to the spike sufficient to evade the antibodies would also reduce the effectiveness of the virus.
The vaccine produces spike
protein within your deltoid muscle cells, where it is rapidly degraded and presented to your immune system. It’s not running around in your bloodstream. Unlike the virus. Which means, incidentally, that if this is a concern of yours you should definitely prefer getting the vaccine to getting an infection.
The question asked by the article is sensible. The uncertainty explored is whether, having had an initial vaccination, future natural infection would produce a better defence against variants than booster shots that target the spike protein alone.
As a public health analysis, there is still a tradeoff between exposure of the population directly to the full spike protein vs in a more constrained vaccine. Especially if, as most governments and economic policies have decided that they are more or less going to forego the bulk of systematic non-medical social measures to protect public health.
And as the paper itself suggests - an even more focused approach to vaccines could be used.
> it means literally nothing for how another person's immune system will behave when they encounter it.
Vaccinations teach everyone's immune system to target the same part of the virus. Since everyone has immunity to the same spike protein, a change in that protein means something to all vaccinated people.
Not inherently. We don't know how it's replicating.
Furthermore, this isn't even an an/or situation: the actual virus in the vial of vaccine isn't going to be 100% uniform. You could have both virus material that can and can't replicate simultaneously. The extra immune response induced by the subset that can replicate might even make the immune response against the spike protein stronger, even if your theory is correct. Remember that vaccines usually have to use adjuvants to induce a stronger immune response than the active part itself does. An actual infection could do that quite effectively.
The point of a vaccine is to not get the actual virus, or at least to minimize its effects if infected.
When you are infected with anything, you do not always develop anti-bodies. If you do develop anti-bodies, they might not be effective at actually stopping you from being re-infected.
Everything about the virus can mutate, but the virus will always target the ACE2 binding site. The spike protein can mutate to bind to it differently, but it will always require a spike protein.
(Biology is Analog, not digital)
Thus targeting the spike protein is more efficient as it will be highly conserved.
There is a video series that does a nice job of breaking down how your immune response works:
https://youtu.be/lXfEK8G8CUI
The vaccine is more effective at developing anti-bodies for the spike protein as it is the only protein exposed during the process.
An analogy that has helped some of my family:
The virus is like a missile, and your immune system is a anti-missile system. Regardless of what the missile looks like, it has to have a warhead, and that warhead is what really defines what the entire thing does. So, if your defense systems targets the fuel of the missile, the enemy can change what fuel it runs on and evade your defense system. They can change the material it is made of, the shape of the overall device, change the propulsion and navigation systems…but the warhead can only have minor changes as it has because it it makes too many, it becomes ineffective and is no longer a threat.
Thus, if your defense system targets the warhead none of the other changes matter.
Oh, it is. I meant that that is also part of 'natural' immunization. The distinction between the 'natural' exposure and the vaccine is that the natural exposure targets a number of epitopes, which may or may not include effective neutralizing antibodies against the spike protein; the vaccine, on the other hand, only offers the spike as an antigen, so you know you're generating neutralizing ab.
Again, this seems counterintuitive to me. If infected, the immune system reacts to foreign bodies. If jabbed, the immune system reacts to foreign bodies. The intention of the shots are to stimulate the same system as a natural reaction, minus the threat of disease. If an individual wouldn’t have a strong response to infection, why would it be any different from a subset of proteins?
Is there academic research on this topic that existed prior to SARS-Cov-2?
Considering that the original virus has this protein as well, I think getting the illness still will be worse. And in vaccine they can control amount of proteins produced. And they can check a lot of things before even hitting human trials, so risk should be minimal.
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)
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