Infectious Disease Outbreaks

A highly contagious norovirus subvariant known as GII.17 has rapidly become the dominant strain in the U.S., driving sharp increases in 'winter vomiting bug' cases across multiple states as national test positivity climbed from 9.9% to 12.11% between Dec. 9 and Dec. 13, according to CDC and health-system data. California hotspots around Los Angeles and San Francisco, as well as states including Michigan, New Jersey, North Carolina, Texas, Oklahoma, Colorado, Alabama, Montana and Wyoming, are seeing notable spikes, raising concerns for vulnerable groups amid simultaneous surges of COVID and influenza.