Coronavirus activity remains on a steep rise in California, with COVID-19 infection and hospital numbers surging as the highly contagious BA.5 subvariant of omicron spreads across the country.

The state’s daily case rate has held relatively flat in recent weeks, reported Tuesday by the California Department of Public Health at 36.1 per 100,000 residents, an 11% decline from one week earlier.

But that is largely due to a continued drop in testing volume, with residents tending toward at-home rapid tests whose results usually go unreported to the state, as well as the July 4 holiday. Labs in California are now processing about 135,000 tests per day, according to the health department, compared to about 235,000 a month ago.

California’s test positivity rate has ascended to 16.1%, approaching the high point from the winter 2020 surge, which peaked at 17.1%. This January’s omicron surge topped out at 22.5%.

The health department reported statewide positivity at 1.4% to start April, 3.1% in early May, 7.3% in the first week of June and 14.9% to begin July.

The state surpassed 4,000 patients hospitalized with confirmed COVID-19 late last week, the first time above that mark since late February, after having dropped below 1,000 in late April.

The health department reported the latest tally at 4,277 in hospital beds with COVID-19, a 20% jump in the past week and California’s highest tally since Feb. 26. The total includes 453 COVID-positive patients in intensive care units, up 15% compared to last week.

The fatality rate is also ticking back up. State health officials reported a seven-day average of 21 virus deaths. That remains well below the original omicron surge’s peak of nearly 275 deaths per day, but is more than double the 10 daily deaths reported in early May and up from 17 at the start of June.

The U.S. Centers for Disease Control and Prevention as of last week classified 38 of California’s 58 counties in the “high” community level for COVID-19, including the four-county capital region of Sacramento, El Dorado, Placer and Yolo, due to high case rates and hospital numbers.

The CDC calls for masking in indoor public places in communities with high COVID-19 transmission. So far, during the current surge, Alameda County is the only California community to reinstate a local health order requiring indoor masking. It rescinded the order in late June.

Health officials in Los Angeles County have said the county will return to a mask mandate if it reaches the high community level. Los Angeles remained in “medium” as of Thursday’s weekly update by the CDC.

Positivity rates have improved to slightly below the state average across most of the capital region and Bay Area, with most of those counties ranging from about 13% to 15%. State data on Tuesday showed Sacramento County at 14.1% positivity.

New contagious variant detected in California

Yet another new and very contagious offshoot of omicron has been recently detected in California, this one known as BA.2.75.

The subvariant is being monitored by the World Health Organization and has been associated with a recent rapid increase in infections in India.

Two cases of BA.2.75 were detected in Bay Area wastewater in June, the San Francisco Chronicle reported.

WHO officials say BA.2.75, which descended from BA.2, appears to be more contagious than BA.5 and has additional mutations outside of its spike proteins.

Experts say it is too early to tell whether BA.2.75 will outcompete BA.4 and BA.5 to become dominant in the U.S. It is also unclear whether there is any difference in severity between BA.2.75 and previously dominant strains of omicron.

BA.5 continues to make up a majority of cases across the U.S. and the West Coast, according to a weekly update Tuesday from the CDC. The variant made up an estimated 65% of nationwide cases last week, up from 54% one week earlier. Its sister subvariant, BA.4, made up 16% of cases each week.

For the CDC region made up of California, Arizona, Hawaii, Nevada and island territories, BA.5 comprised 66% of cases and BA.4 made up 17% last week.