#17,203
Although XBB.1.5 didn't even appear on last week's CDC Nowcast, we've been following a related Omicron variant - XBB - for about a month. Last week it had shot up to about 18% of the known cases (from 7.2% two weeks ago) - although mostly in the Northeastern United States - but this week we learn that most of those cases were actually XBB.1.5, and it is growing at an impressive rate.
Revised estimates (see below) indicate that XBB.1.5 has grown over 30-fold in the past month, going from 1.3% to over 40% of cases in the United States. The parental XBB variant is now estimated to account for about 3.6% of cases.
Right now, the only variant showing consistent growth is XBB.1.5. The briefly dominant tag-team of BQ.1/BQ.1.1 appear to have peaked in early December with about a 63% share of the nation's cases.
While data on this XBB.1.5 is limited, we have seen risk analyses suggesting that it may be the most transmissible, and immune evasive, variant we've seen to date. The rapid (some would say spectacular) rise of XBB.1.5 in such a short time would seem to validate those concerns.
What we don't know is whether XBB.1.5 produces more severe illness than earlier Omicron variants. Hospitalization rates do seem to be rising in regions hardest hit by XBB, but it will take time to sort out the data, and the relative impacts of COVID vs. Influenza vs. RSV.
How long XBB.1.5 will reign, and how bad it will be, remain open questions. For now we know that wearing a face mask can reduce your risks of contracting the virus, and the new bivalent COVID booster shot is believed to be more protective against severe illness (but not necessarily infection) than the older shot.
While pundits, politicians, and the media keep saying that we are nearing the end of this pandemic, the virus apparently hasn't gotten the memo.
And so we begin our 4th year of COVID with a new dominant strain sweeping the nation.
