Thank you for commenting. Gift of Fire really raised a good point - that the variants seem to evolve based on natural immunity because an XBB infection would confer XBB immunity, at least for a few months. So, either XBB stays the same and infects the person months later or evolves to evade XBB-specific immunity.

That said, there's still one concern with immune imprinting - it not only mounts outdated antibodies but may also interfere with the generation of updated antibodies. So, I think the interplay between virus evolution and immunity (from both vaccination and infection) is more complicated than it seems.