First known U.S. Omicron case detected in California

“This is the first confirmed COVID-19 case caused by the Omicron variant in the United States.”

The first known U.S. Omicron case has been found in California, U.S. health officials announced on Wednesday.

That patient – who was fully vaccinated but did not have a booster shot – has mild symptoms, according to Dr. Anthony Fauci, the top U.S. infectious disease official, who briefed reporters at the White House.

“The individual was a traveler who returned from South Africa on November 22 and tested positive on November29th. The individual is quarantining, and all close contacts have been contacted and so far have all tested negative.”

For days, U.S. health officials have warned that the new variant – first detected in southern Africa and announced on Nov. 25 – was likely already in the United States as dozens of other countries also detected its presence.

Fauci said it could take two weeks or more to gain insight into how easily the variant spreads from person to person, how severe it is, and whether it can bypass the protections provided by vaccines.

“As you know and we’ve said this, that the profile, the molecular profile of the kind of mutations that you see, suggests that it might be more transmissible, and that it might elude some of the protection of vaccines, but we don't know that now... We have to be prepared that there's going to be a diminution in protection."

President Joe Biden on Wednesday repeated that the new variant is a cause for concern but not a cause for panic.

Biden said earlier in the week the country would not go back to lockdowns and promised to lay out his strategy on Thursday for combating the pandemic over the winter.