A dangerous new Covid variant from China is surging in California, health officials warn.
The California Department of Public Health warned this week the highly contagious NB.1.8.1 strain has been detected in the state, making it the sixth US state to be exposed.
The variant has also been detected in international travelers arriving in Washington state, Virginia, Hawaii, Rhode Island and New York City since March.
Health officials said the variant was first detected in March and has been on the rise since May 1.
Since April, NB.1.8.1 has increased from two percent of Covid cases in California to 19 percent, according to health department data.
Lab tests suggest NB.1.8.1, which was first detected in January in China, is more infectious than currently circulating strains, which means it could lead to a spike in infections and hospital admissions.
World Health Organization data also suggests it makes up more than half the variants currently circulating.
The warning comes as some physicians in California have called for the return of mask mandates to emulate countries like Hong Kong.