News XBB.1.5, a more contagious variant, now accounts for over 40% of COVID cases January 4, 2023Karen Weintraub, USA TODAYComments Off on XBB.1.5, a more contagious variant, now accounts for over 40% of COVID cases XBB.1.5 makes up more than 40% of cases, the CDC says. While it's more contagious, experts say it seems not to be more dangerous than earlier ones.