Wastewater samples suggest BA.2 variant accounts for half of county cases

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.

County health officer Dr. Ori Tzvieli told the board:

“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.” 

Tzvieli said:

“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. … 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.”

Tzvieli said:

“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.” 

Deputy Health Services Director Randy Sawyer told the board hospitalizations and new cases have continued to fall the past two weeks, but said:

“[T]he 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 he added:

“[W]e have some room for improvement on the booster; only 50.4 percent of those 12 and over have received a booster dose.”

He said:

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

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.”