We do know. It's called Original Antigenic Sin, programming the body to fight the original kind of spike from the original wuhan strain. The spike is what mutates so fast and makes coronaviruses hard to vaccinate against. The nucleocapsid virus would have been a better target and I'll let s/conspiracy guess why the S was used instead of the N for the jabs.

There's also a tendency for the body to not mount a defense against different parts of a virus until the first response has failed. In this case, your body sees a spike from a sars-cov-2 variant and says "oh I know this one" and mounts a response to the original strain. But you're not infected with that, so the current strain runs wild until the rest of the immune response is mounted and you finally beat it back. Then your body says "great job self. We'll remember that, next time we see this spike" except it doesn't remember much of anything except the original S protein if you got the jabs. So there's strong potential for all subsequent infections to inflict severe disease, which we are starting to see reports is happening...but the current variants are pretty mild for everyone jabbed or not, so the difference isn't severe.

The predictions from the "accidentally right all the time" kook fringe is there may come a variant that the jabbed population will suffer horribly from because of OAS and the unjabbed will be in much better shape if they get ill from it.

All this, by the way, was predicted over a year ago by people who were deplatformed for spreading disinformation at the same time mainstream press outlets were being paid by the government to promote the jabs.