By CBSLA Staff

LOS ANGELES (CBSLA) — The first U.S. case of the Omicron variant of COVID-19 has been detected in California.

Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases and the Chief Medical Advisor to the President, delivers an update on the Omicron COVID-19 variant at the White House on Dec. 1, 2021, in Washington, D.C. (Getty Images)

The Centers for Disease Control and Prevention, along with the California Department of Public Health, confirmed Wednesday that the case was detected in a traveler who returned from South Africa on Nov. 22.

The variant was detected using genomic sequencing by researchers at the University of California, San Francisco.

According to the CDC, the person was fully vaccinated and has had mild symptoms so far. All the patient’s close contacts have tested negative so far.

“This is not a surprise. For those of you that have been following this, we knew that Omicron was going to be here, we thought it was already here, we just hadn’t detected it yet,” San Francisco Health Director Dr. Grant Colfax said in a news briefing Wednesday. “So this is cause for concern, but its also certainly not a cause for us to panic.”

California Gov. Gavin Newsom reacted to the news on Twitter.

“CA’s large-scale testing and early detection systems have found the Omicron COVID-19 variant in California,” he wrote. “We should assume that it’s in other states as well. There’s no reason to panic–but we should remain vigilant. That means get vaccinated. Get boosted. Wear a mask indoors.”

State and Los Angeles County leaders have said they do not plan to issue new lockdowns as a means of preventing Omicron from spreading. UCLA epidemiologist Dr. Anne Rimoin told CBSLA Wednesday the most important thing is surveillance.

“We’re going to have to look for it,” Rimoin said. “All of the sequencing that we’re doing now that is ramping up—I have a feeling we’re going to have a lot more information soon.”

The Omicron variant was first reported in South Africa last week. Although not much is known about its transmissibility or severity, there is concern because it has a high number of mutations.

This has prompted the World Health Organization to designate it a “variant of concern.”

“The Omicron variant is the most divergent variant that has been detected in significant numbers during the pandemic so far which raises serious concerns that it may be associated with significant reduction in vaccine effectiveness and increased risk for reinfections,” European health officials said Friday, according to CBS News.

The White House has banned international travelers from eight countries in Southern Africa, including South Africa, Botswana, Zimbabwe, Namibia, Lesotho, Eswatini, Mozambique and Malawi. The ban does not apply to U.S. citizens or permanent residents.