Sorry but what's the source that mRNA boosters work against Omicron ? I thought it's more like the vaccines neutralize threat from the original 2-3 variants and

Sorry but what's the source that mRNA boosters work against Omicron ? I thought it's more like the vaccines neutralize threat from the original 2-3 variants and Omicron isn't deadly in and of itself. Also maybe this is China specific paranoia since neighbouring India doesn't care much and they seem to be doing fine wrt Omicron.