Omicron is WHO's generic name for a group of several variants, of which includes the BA-5 and BA-4.6 types. Those two account for 95% of all new infections this past week.
Someone commented about waiting for the omicron variant to be included in the newest vaccine. Not sure what they meant about that? Perhaps they mis-spoke because this 3rd booster does specifically targets that.
Look here for up to date statistics on infection rates broken down by variant version.
CDC COVID Data Tracker