San Francisco now has the third-highest coronavirus transmission rate in California, with a daily average case rate of about 104 per 100,000 residents.
The county recorded a seven-day average of 896 cases per day on Dec. 30, the most recent available data. That is more than double the previous peak of 388 cases, a seven-day average recorded on Jan. 12 last year.
At least one Bay Area county, Napa, is out of available intensive care beds as the virus once again tightens its hold on the region.
San Francisco’s transmission rate ranks in California behind only Los Angeles County, with 118 cases per 100,000 residents — the highest reported there since the start of the pandemic — and Mono County with 109 per 100,000. Across California, the seven-day average is 75 cases per 100,000, and in the Bay Area, it is 63 cases.
San Francisco officials said infections among staff members are starting to affect city departments. The Municipal Transportation Agency said Monday in a memo obtained by The Chronicle that it is implementing COVID protocols at its offices on South Van Ness Avenue after an outbreak involving several staff members.
COVID-19 hospitalizations in the Bay Area also hit their highest number since mid-September over the weekend.
Data analyzed by The Chronicle shows 746 Bay Area hospital patients testing positive with the coronavirus as of Sunday — a figure not seen since the tail end of the summer delta surge. Of those patients, 149 were in intensive care unit beds — a 50% jump since Christmas.
That is already putting stress on some hospital systems in the region. Napa County has no ICU beds currently available, said Leah Greenbaum, the county’s emergency services coordinator.
“The current surge is driving more patients to the health care system, and it is also impacting staff,” she said. “When staff become infected with COVID-19 they cannot come into work and care for patients, which can cause significant strain on the health care system.”
The number of hospitalizations in the Bay Area, a lagging indicator of pandemic trends, has risen sharply since mid-November with the spread of the omicron variant and the persistence of the delta variant, and it shows no sign of abating.
Bay Area health officials expect the number to continue to surge as people return to work and school after traveling and gathering over the winter break, with students at most Bay Area schools returning from holiday on Monday.
“The combination of the omicron variant being highly transmissible and holiday gatherings are contributing to the increase in the number of COVID-19 cases in Solano County, in California, and across the nation,” said Jayleen Richards, public health administrator for Solano County.
Home kits to test for coronavirus infection are ready to be handed out by Alameda County health officials to families at Canyon Middle School in Castro Valley ahead of students’ return from winter break.
Brontë Wittpenn/The Chronicle
By comparison to San Francisco’s reported daily average of 104 new cases per 100,000 residents, Marin County reported about 80 cases per 100,000 people as of Dec. 30, with San Mateo County at about 68, Napa at 66, Sonoma at 59, Contra Costa at 58, Santa Clara at 57, Alameda at 55 and Solano at 43.
“We are seeing a rapid increase in cases in Napa County,” said Greenbaum. “We have exceeded the peak of the delta surge, and we have nearly as many cases as we did during the winter surge last year.”
Schools in Napa County will not reopen for another week, she added, “but we know many residents resumed more traditional holiday gathering and travel plans this year.”
The good news within the escalating figures is that the number of hospitalizations remains well below what it was a year ago, with a peak of 2,210 on Jan. 10, when vaccines were still just emerging. Some health officials warned however that a continuing upward trend may stress medical facilities.
“We are seeing substantial increases in the numbers of adults in hospitals with COVID-19. But with high levels of virus circulating locally, at least some of these people are likely hospitalized for other reasons and had COVID-19 diagnosed on routine screening,” said Neetu Balram, public information manager for Alameda County.
People stand in line to shop at Ver Brugge Meat-Fish Poultry along College Avenue in Oakland, masked up as the highly transmissable omicron variant of the coronavirus takes hold in the Bay Area.
Jessica Christian/The Chronicle
“Intensive care unit COVID-19 hospitalizations are also rising locally, and this may put our hospitals under stress in the coming weeks.”
About 25% of the Bay Area’s intensive care unit beds remain available, according to state data.
“We still have capacity in our hospitals, but continue to monitor the situation,” the Santa Clara County health department said.
Nationwide, there were 103,329 patients hospitalized with COVID-19 as of Monday, according to data from the U.S. Department of Health and Human Services. About 20% — 18,557 — are in intensive care unit beds, among hospitals reporting to the agency. The number is fast approaching the benchmark of 104,000 hospitalizations reported in September at the peak of the delta COVID surge.
As Bay Area students flooded back into schools Monday, the Food and Drug Administration approved Pfizer booster shots against the coronavirus for children as young as 12, to enhance protection in the face of the omicron variant’s ability to evade vaccines. The Centers for Disease Control and Prevention expects to rule on the recommendation later this week.
The FDA said everyone 12 and older eligible for a Pfizer booster can get one as early as five months after their last dose. Boosters already are recommended for everyone 16 and older.
Children tend to suffer less serious illness from COVID-19 than adults, but child hospitalizations are rising during the omicron wave — most of them unvaccinated.
“Hopefully, this will be not just a call for people to go get their booster shot,” but for the tens of millions of unvaccinated Americans to rethink that choice, said FDA vaccine chief Dr. Peter Marks. “It’s not too late to start to get vaccinated.”
San Francisco Chronicle reporters Erin Allday and Mallory Moench contributed to this story.
Aidin Vaziri is a San Francisco Chronicle staff writer. Email: avaziri@sfchronicle.com