Cases surging in Bay Area, state

California is seeing a post-Thanksgiving surge in COVID-19 cases as the worrisome omicron variant spreads through the Bay Area, with Santa Clara County reporting its first case and warning that recent wastewater samples indicate there are plenty more on the way.

The rise in cases locally and around the state marks a reversal from hopeful signs heading into the holiday, when California’s virus transmission rate had finally started to level off and then subside. But delta, and now omicron, is not done with us yet — although federal officials released hopeful if sketchy data Dec. 10 indicating omicron so far has caused just one known hospitalization in the U.S. and no deaths.

Santa Clara County health officials said their first omicron case is an adult resident of the county who was fully vaccinated and recently returned from a trip to Florida. The person was just coming due for a booster and was planning to get one but felt ill Nov. 30. The person has mild symptoms and is in isolation, as are close contacts who have been notified to be tested.

“Ever since we first learned about omicron, we have been anticipating a detection here because our population is large and our population is diverse and our population is mobile,” said Santa Clara County Health Officer Dr. Sara Cody. “I anticipate that we will hear of many more omicron detections in the very near future.”

County health officials said wastewater surveillance for the first time also indicated the likely presence of omicron in an area of about 213,000 residents in the northern part of the county, where the infected person lives. It is one of four sewersheds the county monitors, from Palo Alto and Stanford to Los Altos, Los Altos Hills and Mountain View. The sample was taken Dec. 7.

Alexandria Boehm, a Stanford University civil engineering professor who is assisting the county with wastewater surveillance for the virus, said they were able to identify fragments of omicron’s genetic code and a specific mutation characteristic to that variant.

“We detected a very high number of these segments of omicron in the north county wastewater,” Boehm said.