by For most of the summer, COVID levels in California and the San Francisco Bay Area were high.
The test positivity rate reached 14.3%, an increase of more than 2 percentage points from the previous week, according to Friday’s update from the California Department of Public Health. That’s the highest positivity rate in a year.
After increasing for three months, the positivity rate is quickly approaching the record positivity rate for a summer surge — 16% in July 2022.
Although testing data is no longer available locally, Santa Clara County wastewater shows that the virus has been spreading at high levels for several weeks. All four sewer basins — Palo Alto, Sunnyvale, San Jose and Gilroy — have “high” concentrations.
In Contra Costa County, wastewater also has high concentrations of the virus, and the county’s public health department this week urged residents to wear masks in crowded indoor settings, “especially for those at high risk of severe illness if infected.”
“Face masks are an effective tool to reduce the spread of the virus,” Contra Costa County Health Officer Dr. Ori Tzvieli said in a statement. “This is one of those times. Our health care system is not seriously impacted by COVID right now, and our goal is to keep it that way.”
Dr. John Swartzberg, clinical professor emeritus of infectious diseases and vaccinology at UC Berkeley, calls Contra Costa Health’s recommendation “excellent advice.”
“There are still too many people hospitalized and too many people dying,” Swartzberg said, noting that the annual number of COVID deaths still exceeds the number of deaths during a normal flu season.
Contra Costa Health attributes the current prolonged surge to the FLiRT variants currently spreading in the western part of the country, which they call “particularly infectious.”
“We didn’t get a long reprieve after the winter surge,” Swartzberg said. He also attributes the virus’s stubborn advance this spring and summer to the current round of variants. “The Omicron subvariants continue to produce new subvariants that are more transmissible and more immune-evasive.”
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