Yeah, an immune response specific to the Omicron variant would likely be more effective against Omicron for obvious reasons, but it's probably not possible to g

Yeah, an immune response specific to the Omicron variant would likely be more effective against Omicron for obvious reasons, but it's probably not possible to get one in people with immunity to older variants because their existing immunity gets in the way. This isn't too surprising - it's one of the things that seems to limit the effectiveness of the flu vaccine.