unpleasant thought about boosters, variants, and lasting antibody immunity

What happens when you get a booster shot? Same thing as usual: B cells responsive to those antigens multiply, and diversify, randomly mutating in case they get a better fit.

So even if all your shots are against original covid, and you then get hit by Delta or even Omicron, some of those mutated B cells and antibodies may be responsive to the variant, and then your immune system will shift over and learn.

But what happens if you never do get infected? Antibody levels drop, and B cells get selected for specificity against the antigen your body actually knows about.

Which isn't Delta, or Omicron. If you've never seen Omicron spike protein, you literally have no reason to keep around B cells specific to it.

Which suggests the boosters really do have a temporary effect against variants, working just by restoring a diverse population of covid-ish antibodies, some of which might include the variants. But without exposure, you'll never keep B cells for those variants.

Which would mean Fauci is wrong about not needing omicron boosters. Sure, get a booster now, to benefit from that higher and more diverse level of antibodies, but in the long term you need an omicron vaccine to hope to prevent infection.

Or, if you live dangerously and don't think they'll make new vaccine types, get a booster and then go expose yourself while you're at peak resistance, so you body can learn from direct exposure.

I would love to be wrong, but this is where my lay knowledge of immunology takes me.