First US case of Omicron found in California

The Centers for Disease Control and Prevention say the omicron variant of the coronavirus in the U.S. has been found in a person in California.

From NBC News:

The CDC issued a statement that the California and San Francisco Departments of Public Health confirmed the case in a traveler who returned from South Africa on November 22. 

"The individual, who was fully vaccinated and had mild symptoms that are improving, is self-quarantining and has been since testing positive," the statement read.

The variant, which was first detected in southern Africa last week, has a high number of mutations that suggest it may spread just as or more easily than the delta variant, which currently accounts for 99.9 percent of Covid-19 cases in the U.S.