COVID is spiking again in California. What experts say about new variants, mask requirements

After a brief dip in mid-December, California’s coronavirus transmission rates appear to be climbing once again as 2022 comes to an end, with a key metric reaching its highest point in more than four months, state health data show.

The California Department of Public Health in a weekly update Thursday reported the statewide case rate for COVID-19 at 16.9 per 100,000.

Though that is a 12% drop compared to one week earlier, testing volume also dropped significantly, likely due to the winter holidays.

As a result, California’s test positivity rate spiked to 11.9%, up from 10.5% one week earlier for the state’s highest percentage recorded since Aug. 10.

Hospitalizations with COVID-19, which tend to lag behind case increases by about two weeks, increased minimally in the past week. CDPH reported 4,561 virus-positive patients in California hospital beds as of Thursday’s update, up 1% from one week earlier.

Health officials continue to warn that virus spread is likely to increase in the coming weeks, following travel and gatherings to celebrate Christmas and other winter holidays.

At the global level, experts are concerned by a major surge underway in China. U.S. health officials on Wednesday announced that travelers flying to the U.S. from China will be required to show a negative COVID-19 test starting Jan. 5.

Masks could return to some Sacramento schools

Sacramento City Unified School District officials said students and staff will return to an indoor mask requirement upon return from winter break Jan. 9 — but only if Sacramento County is classified by the U.S. Centers for Disease Control and Prevention in the “high” community level for COVID-19 danger in the preceding weekly update, posted Jan. 5.

The county entered the high community level last week, placed in that designation for the first time since late July.

Federal health officials advise masking up in public indoor settings in counties with a high community level for COVID-19, which is a classification the CDC calculates based on local case and hospitalization rates.

The CDC updates community level assignments weekly, on Thursday afternoons. Twenty-two of California’s 58 counties were in the high community level as of last week’s update, including Alameda, Fresno, Merced, Orange, San Francisco and Ventura.

Sacramento neighbors El Dorado, Placer and Yolo counties remained in the “medium” community level last week due to lower case rates.

XBB variant increasing in U.S.

The U.S. Centers for Disease Control and Prevention, in a weekly update last Friday, reported the XBB subvariant of omicron as making up 18% of cases nationwide, up from 11% the preceding week and 7% two weeks earlier.

The acceleration comes just weeks after two sister variants, BQ.1 and BQ.1.1, became the dominant strain circulating nationwide. Those two variants still made up the majority of U.S. cases, combining for 63% in last week’s update from the CDC. They overtook BA.5, which fueled the summer COVID-19 wave, in early November.

XBB has gained an early foothold in New England, where CDC data showed the variant accounting for 53% of new cases last week.

In the CDC’s West Coast region, which includes California, XBB comprised only 8.8% of recent cases, up from 6.7% the preceding week.

As with other omicron subvariants of concern, health officials say XBB appears to be better at evading immune protection than previously dominant variants.

Sacramento-area numbers by county

Sacramento County’s latest case rate is 15.1 per 100,000 residents, state health officials said in Thursday’s update, down 7% decrease from one week earlier.

Hospitals in Sacramento County were treating 220 patients Wednesday, state data updated Thursday showed, down from 243 one week earlier. The intensive care unit total decreased to 23 from 34.

Placer County’s latest case rate is 13 per 100,000 residents, an 18% increase from one week earlier.

Hospitals in Placer County were treating 109 virus patients Wednesday, up from 100 one week earlier. The ICU total increased to seven from six.

Yolo County’s latest case rate is 9.9 per 100,000 residents, a 15% decrease from one week earlier.

Hospitals in Yolo County were treating nine virus patients Wednesday, up from five a week earlier. The ICU total remained at zero.

El Dorado County’s latest case rate is 11.5 per 100,000 residents, a 4% increase from one week earlier.

Hospitals in El Dorado County were treating four virus patients Wednesday, down from 11 a week earlier. The ICU total decreased to one from two.

Sutter County’s latest case rate is 11.5 per 100,000 residents, down 14% from last week, and Yuba County’s is 14.2 per 100,000, up 5%, state health officials reported Thursday.

The only hospital in Yuba County, which serves the Yuba-Sutter bicounty area, was treating 15 virus patients Wednesday, up from 11 a week earlier. The ICU total increased to one from zero.