COVID variant NB.1.8.1 hits U.S. What to know about symptoms, new booster vaccine restrictions

Cases of the new COVID-19 variant NB.1.8.1, linked to a large surge in China, have been detected in multiple locations across the United States, according to the Centers for Disease Control and Prevention.

"CDC is aware of reported cases of COVID-19 NB.1.8.1 in China and is in regular contact with international partners," a CDC spokesperson said in a statement last week.

The spokesperson said that, so far, too few U.S. sequences have been reported of NB.1.8.1 to be included in the agency's variant estimates dashboard.