Santa Clara County health officials on Friday reported detecting the county’s first case of the Omicron variant, which has been widely anticipated by health officials since the variant first made its way to the United States earlier this month.

The variant was detected in a resident who had recently returned from domestic travel, and while fully vaccinated, had not yet received the Pfizer-BioNTech COVID-19 vaccine booster. The individual is currently in isolation. 

“The main message now is the importance of boosters — two initial shots are not enough,” said Dr. Marty Fenstersheib, the county’s vaccine officer. “Boosters have been shown to offer a great deal of additional protection from serious COVID-19 infection.”

Santa Clara County’s test positivity rate currently sits at 1.7% to the broader state’s 2.7%, a level that it’s hovered at since mid-September. During last winter’s surge, the county’s test positivity rate sat at around 9%.

79.4% of county residents in all age groups have been fully vaccinated, while 90.8% of residents ages 12 and up and 84.5% of residents ages 5 and up have done the same. All adults — and, as of Thursday, 16- to 17-year olds too — are eligible for the booster shot. Santa Clara County residents can schedule an appointment at sccfreevax.org.