The United States has for the first time detected a case of the highly mutated Omicron coronavirus variant, which the World Health Organization has labeled a “variant of concern.” Top infectious disease scientist Dr. Anthony Fauci made the announcement at the White House Wednesday. 

Dr. Anthony Fauci: “We knew that it was just a matter of time before the first case of Omicron would be detected in the United States. … The individual was a traveler who returned from South Africa on November the 22nd and tested positive on November the 29th.”

The Omicron variant has now been detected in over two dozen countries. Its discovery in San Francisco prompted the White House to renew calls for Americans to get vaccinated if they haven’t already — and to get booster shots, if eligible.

Meanwhile, President Biden is reportedly planning to extend a mask mandate for travelers on airplanes, trains and buses and at airports and transit stations. The mandate was set to expire in mid-January but will now run through at least mid-March.