First known U.S. case of Omicron variant identified in California

The first known U.S. case of the Omicron variant was detected in California, the Centers for Disease Control and Prevention confirmed Wednesday.

Driving the news: The confirmed case was detected in a traveler returning from South Africa who was fully vaccinated and has mild symptoms, according to the CDC.

• The person, who California Gov. Gavin Newsom (D) said is a resident of San Francisco and tested positive on Nov. 28, is self-quarantining. All close contacts have been notified and tested negative, according to the CDC.
• The individual had not yet received a booster shot, NIAID director Anthony Fauci also noted in a White House press briefing.

What they're saying: "The recent emergence of the Omicron variant ... further emphasizes the importance of vaccination, boosters and general prevention strategies," the CDC said in a statement.

• "We know what we need to do to protect people," Fauci said at the White House briefing following the CDC announcement. "Get vaccinated if you're not already vaccinated," he added. "If you’re eligible for boosting, get boosted right now.”
• White House COVID-19 response coordinator Jeff Zients said in a statement later Wednesday: "The President’s medical team continues to believe that existing vaccines will provide some level of protection against severe illness from Omicron, and individuals who have gotten boosters have even stronger protection."
• Newsom echoed the administration officials in a tweet, saying there’s "no reason to panic--but we should remain vigilant. That means get vaccinated. Get boosted. Wear a mask indoors."

The big picture: Since the variant was first identified by scientists in South Africa earlier last month, Omicron cases have been confirmed across Europe, Canada, Israel, Hong Kong and Australia, among other countries.

• The U.S. was one of several countries to impose travel restrictions on southern African nations in response.
• Dutch scientists confirmed Tuesday the variant had been circulating in the Netherlands before it was discovered in South Africa.

What to watch: President Biden is expected to discuss the administration's plan for fighting the virus through the winter on Thursday.

• "We're going to fight COVID this winter. Not with shutdowns or lockdowns, but with more widespread vaccinations, boosters, testing and more," Biden said earlier this week.

Go deeper: Omicron dashboard

Editor's note: This story has been updated with additional details throughout.