New COVID subvariant XBB. 1.55 is accelerating

The XBB.1.5 COVID-19 subvariant — a new version of the omicron variant — is sweeping through the United States right now amid a chaotic travel season and the early days of winter, reports Axios. Cases tied to the new variant nearly doubled to 40% of confirmed U.S. cases for the week ending Dec. 31, up from 20% for the week ending Dec. 31, according to estimates from the Centers for Disease Control and Prevention.