CDC tracking rise of new XBB.1.5 COVID variant, already more than 40% of U.S. cases

The Centers for Disease Control and Prevention said Friday it is tracking a new variant of concern dubbed XBB.1.5. According to new figures published Friday, it estimates XBB.1.5 makes up 40.5% of new infections across the country. 

XBB.1.5's ascent is overtaking other Omicron variant cousins BQ.1 and BQ.1.1, which had dominated a wave of infections over the fall. Scientists believe its recent growth could be driven by key mutations on top of what was already one of the more immune evasive strains of Omicron to date.

"We're projecting that it's going to be the dominant variant in the Northeast region of the country and that it's going to increase in all regions of the country," said Dr. Barbara Mahon, director of the CDC's proposed Coronavirus and Other Respiratory Viruses Division, in an interview with CBS News.