CONTRA COSTA COUNTY (CBS SF) – Health officials in Contra Costa County confirmed their first cases of the omicron variant of COVID-19, while urging residents to receive booster shots and to be cautious heading into the holidays.

According to Contra Costa Health Services, three cases of the variant were found through genomic sequencing. The variant was detected during tests of county wastewater earlier this month.

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“We knew it was just a matter of time before the omicron variant appeared in Contra Costa County,” health officer Dr. Chris Farnitano said in a statement on Monday.

Two of the cases in the county were in people who were fully vaccinated but without a booster shot, while the third case was in an unvaccinated person. Officials said none of the omicron patients have been hospitalized so far.

Contra Costa health officials said omicron has likely been circulating in the community for several weeks. The rapidly spreading variant, first discovered a month ago, has been found in other Bay Area counties since start of December, with health officials expecting “many more cases” in the weeks to come.

While the omicron variant is spreading, health officials stressed that most COVID-19 cases in the county so far remain the delta variant.

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Health officials said the seven-day average of new COVID-19 cases in Contra Costa County has increased about 5% in the past two weeks. Hospitalizations from the virus have been stable so far in December.

Farnitano again urged residents to get their COVID-19 vaccine booster. As of Monday, only about a third of eligible county residents have received their third dose.

“With today’s news and the holidays just around the corner, that message is even more important. People who get the booster are far less likely to get gravely ill or be hospitalized. That’s our wish for this holiday season,” the health officer said.

While officials said the vaccinated do not need to cancel holiday plans, officials urged residents to take precautions, including staying home and testing if they develop symptoms, to test before and after travel or attending gatherings, and to wear masks in indoor public spaces.

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Information about COVID-19 vaccines and testing can be found by visiting the Contra Costa Health Services website or by calling 833-829-2626.