A warning sign about COVID-19 restrictions at the Lafayette Reservoir in Lafayette, Calif., on May 7, 2021, part of East Bay Municipal Utility District's (EBMUD) water system, serving approximately 1.4 million people in a 332-square-mile area of Contra Costa and Alameda counties in California. (Samantha Laurey/Bay City News)

COVID-19 cases and hospitalizations are still declining in Contra Costa County, health officials told the county Board of Supervisors on Tuesday, though new strain BA.2 is appearing in greater quantities in county wastewater samples.

“The BA.2 is a subvariant of omicron and we’re still learning about it but, there’s some research suggesting that it’s more contagious than the original omicron that we had here, which was called BA.1,” county health officer Dr. Ori Tzvieli told the board.

“Right now, COVID-19 transmission is down in our county, and we just came out of a surge, but we have some evidence that BA.2 is becoming more prevalent in our county,” Tzvieli said. “Every week it’s a higher percentage of the cases and we are concerned that this may lead to an increase in cases and hospitalizations in the coming weeks, so we are keeping a close eye on it. It’s very hard to predict what will happen.

“But recent wastewater sampling suggests this subvariant is accounting for about half the cases in our county, so far. And we’re also doing whole genome sequencing to monitor the situation,” Tzvieli said.

Deputy director of health Randy Sawyer told the board hospitalizations and new cases have continued to fall the past two weeks, but said “the declines have definitely slowed and are starting to flatten out.”

The average number of new cases per day over the past week is down to 73, which is 13.4 percent lower than the previous week. The number of people hospitalized with COVID-19 in Contra Costa is at 35, down 24.4 percent from one week ago.

Tzvieli said nearly 81 percent of all county residents are fully vaccinated, but “we have some room for improvement on the booster; only 50.4 percent of those 12 and over have received a booster dose.”

“If you’re eligible for a booster, we strongly recommend getting one; it’s the best way to protect yourself, to protect your community,” he said.

Tzeveli also said that though state and county mask mandates have been lifted, masking “is still strongly recommended in public indoor spaces, particularly for those who are elderly or immune-comprised or high risk.”