Not great news re: Omicron boosters. This is an animal study, so it's not necessarily how it'll play out in humans, but it found that an Omicron-specific booster actually produced fewer antibodies capable of neutralizing Omicron than just using another dose of the original vaccine (which we know has limited duration of protection against Omicron). There are probably 2 likely possibilities for why that's happening:
1) Omicron is so divergent from the other variants that a single dose isn't enough to generate a good response.
2) Our immune response is sort of locked in to the first exposure and will tend to favor that even in the face of other variants. That's known as "imprinting" or "original antigenic sin".
Unfortunately, if #2 is the case, it's also going to apply to infections (possibly even more so), which means that the immunity generated from infections that we're seeing right now might not be as robust as it was in prior waves.
https://www.biorxiv.org/content/10.1....479037v1?s=08