[F30]

It's a matter of antibody levels. Antibody binding is worse for Omicron, so you need more of them. Booster shots provide you with such increased antibody levels.

Are they still gonna be high enough after a few months? Good question. Afaict, nobody knows yet.

(And this of course leaves aside the whole matter of T-cell immunity still providing protection against severe disease.)

[roenxi]

It looks like there might be more factors at play here than that. Natural immunity does a lot better than being only vaccinated, which suggests there is some sort of issues related to quality as well as quantity of antibodies.

[orra]

> And this of course leaves aside the whole matter of T-cell immunity still providing protection against severe disease.

Quite. But it’s hard to quantify so we don’t bother.