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christophersonne t1_j9u8xl5 wrote

There have been very few infections in Humans over the last 25 years (under 1000 confirmed last time I checked), and mostly they happen in places that a flu vaccine isn't widely available or used. So, we really have no idea in a real-world sense.

The problem with H5N1 that could cause serious problems is a mutation/variatnt that would allow for human-to-human transmission , which the current variant doesn't have - so a human-affecting pandemic of H5N1 would be a fundamentally different variant to the strain(s) we know of today.

The mutation needed to H2H transmission may or may not affect the protection afforded by a flu vaccine. Think about how different Covid has been, variant to variant, and with the various vaccines we have.
(tldr: more data required)

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Esc_ape_artist OP t1_j9ubn2v wrote

Good point. The potential H2H variant could render the current H5N1 vaccine useless.

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PirateNinjasReddit t1_j9xsy9e wrote

It's unlikely to render it useless. Most likely it would just be less effective. Like how COVID vaccines offer more or less protection from variant to variant, but never do they offer no protection at all.

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platoprime t1_j9y53wa wrote

How different does a virus need to be for a vaccine to be useless? Or does a vaccine protect against all viruses a tiny bit?

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Taboc741 t1_j9ykeyh wrote

Viruses on their outside are a collection of well fitting proteins. It turns out the shape of a protein is very important, it lets the protein do its "job". Or as much of a job as a physical shape can have. Think of a hammer, its shape makes it very good and driving nails but not very good at smoothing concrete. These viral protein shapes allow the virus to attach to human cells, open the cell wall and "inject" the malicious genetic code to the cell. Antibodies attach to those protein shapes and can rip apart the virus, make it easy for immune cells to find and destroy, and/or prevent the virus from attaching to human cells.

Each mutation in a virus alters the proteins and their shapes a little. Too much mutation and none of the parts fit and it is no longer self replicating. So asking how different does it need to be is a very difficult question to answer. A little bit and the various shaped antibodies the body produces will still bind to some of the virus's protein shapes, a little more and it might stop attaching to human cells (though it might attach to a different animal cell and thus you've found a variant that is ready to hop species), and too much more and now you've either killed the virus or it's something new entirely.

Tldr: these mutations affect the very being of the virus, too many and it stops being the virus it is.

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annaheim t1_j9vjs18 wrote

Is H2H transmission mutation similar to all diseases? Like, if it's composes of the same component. Can fungus evolve to have this mutation?

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Dr_Vesuvius t1_j9xme1z wrote

No, not at all. Human-to-human transmission is not a biological component, like a human leg, but a biological process, like movement. There are many different things that go into human-to-human transmission, but it comes down to getting into the body, reproducing, and getting out again. There are many different ways to achieve those things. The flu is spread very differently to HIV, which is spread very differently to malaria, which is very different to Legionnaire’s Disease.

Edit: although to clarify, Legionnaire’s Disease isn’t usually spread human-to-human, and malaria is debatable. Cholera would be been a better example of a waterborne disease that enters through the digestive tract.

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Botryllus t1_j9xd7fx wrote

Could they get a head start on a vaccine by looking at a conserved protein in virus so that they're ready if it jumps?

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