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Comment by bavell | Hacker News Reader

> I don’t think that your model of how vaccines work really makes sense.

I believe OP is referencing "Original antigenic sin" [0].

"This leaves the immune system "trapped" by the first response it has made to each antigen, and unable to mount potentially more effective responses during subsequent infections."

[0] https://en.m.wikipedia.org/wiki/Original_antigenic_sin

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If this was true vaccines would be ineffective against Delta and other mutated variants, but it turns out the vast, vast majority of cases that are severe or result in death are among the unvaccinated.

This is just bad science and isn't supported by real-world outcomes.

Also adaptation of antibodies evidently works, as cross-vaccination schemes improve response rates. E.g. 2 doses Moderna, then 1 dose BionTech and vice versa, is better than 3 doses of the same for either one.

https://twitter.com/Karl_Lauterbach/status/14516437827855564...

Doesn’t make sense. If the infection continues the immune system will generate new antibodies and responses. After all it’s a new thing not seen before.

The linked article both describes the mechanism and has plenty of recent references observing and studying the effect whether or not you think it makes sense.

The general mechanism is that recognition of the antigen by memory B cells produces a response that also inhibits (non-memory) B cells from reacting to the antigen. So when the antigen has drifted enough that memory B cells still recognize it, but the antibodies are less effective then at that point B cells are actively inhibited by the memory B cells so new and retargeted antibodies are not produced.

So, down the line, you might be more susceptible to a similar mutation. (Based on no hard evidence for this particular virus).

(Social media reports aren’t exactly reliable and everything seems to indicate that your chances of serious complications are worse without a vaccine).

Right now, there’s a deadly virus going around and there might not be a “later” for me if I don’t get the vaccine. I think I’ll take my chances with the vaccine. It seems like a no brainer to me.

There is hard evidence. I’m on mobile and can’t look well now, but I encourage you to look!

Eventually you clear the infection in most cases. How do you think that happens?

It happens the same way. This is just talking about rates. When naive B cells see that existing antibodies are already present on the virus they take that as a signal that memory B cells already exist and the search for new antibodies is called off. So there's a balance between the quantity of virus, how quickly the virus replicates, quantity of antibodies, how well the antibodies bind to the virus, and how many bound antibodies are needed on a virus to suppress the naive B cell response. Basically, if binding becomes less efficient you'd expect the viral load to have to get higher before naive B cells get significantly involved. And in fact the infection may just be cleared without involving naive B cells, but just take a bit longer. It seems unlikely that would be worse than not being vaccinated, but I'm sure the devils are in the details of all these factors.

> When naive B cells see that existing antibodies are already present

I don't think this is how this works.

They "see" antibodies sticking to a target, as successful antibodies are presented for replication and refinement. This implies a functional response. If the vaccine antibodies wouldn't work on a new strain, the B cells wouldn't recognize them as suitable candidates.

I thought about this a bit more… there’s no reason this wouldn’t apply to a secondary infection with a different strain of covid is there? I don’t see what’s special about the vaccine that would make this effect noticeably worse than simply being infected twice.

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