Coronavirus infections and hospitalizations are again climbing in the Bay Area as the region enters what public health officials say is the sixth wave of the COVID-19 pandemic.
San Francisco now has the second-highest rate of infection in California, with an average of 40 new daily cases per 100,000 residents, according to state data published Friday, behind nearby Santa Cruz County, which reported 43 per 100,000.
Both counties were reporting just 3 daily cases per 100,000 a month ago.
“I’m surprised it’s going up as much as it is,” said Dr. George Rutherford, an infectious disease expert with UCSF.
San Francisco, Santa Clara, Marin and San Mateo counties — as well as Santa Cruz — had all moved into the “moderate” level for community COVID presence as of Friday, as measured by the U.S. Centers for Disease Control and Prevention. The calculation is based on case rates and hospitalizations. At that level, the agency recommends that high-risk individuals again use face masks inside public spaces.
All nine Bay Area counties, plus those surrounding the Sacramento-San Joaquin River Delta and virtually the entire California coast, are also classified as having “high” virus community transmission rates, according to a separate CDC metric.
“There’s a lot of transmission happening,” Rutherford said. “Nobody is wearing masks. We’re not at that same level of avoidance we were earlier.”
He added that the highly contagious BA.2 omicron subvariant and its sublineages, such as BA.2.12.1, may be causing the current rise in cases, especially with waning immunity in both people who were vaccinated last year and those who were previously infected with the original omicron strain in the winter.
“I think the vaccines are working great on preventing hospitalizations and deaths,” Rutherford said. “But their ability to prevent transmission is not as good as it has been.”
Hospitalizations are starting to tick up, too. Across the Bay Area, there are now 322 people hospitalized with the virus, compared with 245 people a month ago. San Francisco reported 55 patients with COVID-19 on Friday. That number was 23 on April 6. COVID admissions to Bay Area intensive care units also climbed to 50 as of Thursday, compared with 29 a week earlier.
These figures remain well below those logged during earlier COVID waves when fewer people were vaccinated and new treatments, such as antiviral medications, weren’t yet available.
The city’s coronavirus test positive rate has edged up to 8.7%. That is more than double California’s overall rate of 3.9% and appears to be rising sharply.
“We’re going to continue to see increases in transmission,” Rutherford said. “We’ll see cases. We’ll also see some hospitalizations and deaths, but not as many as we saw in the past.”
The newly detected BA.4 and BA.5 subvariants, which have caused another surge in South Africa, are also clouding the future of the pandemic.
“Those could make things worse,” Rutherford said. “I expect there’s going to be a sawtooth pattern going forward.”
Health officials in Santa Cruz County this week urged residents to “protect Mom by wearing a mask and visiting in areas with good ventilation” for their Mother’s Day celebrations.
Dr. Cal Gordon, the Santa Cruz County deputy health officer, told television station KSBW that the county is seeing “sneaker waves” of new cases but was uncertain if that would lead to a surge.
Deaths, a lagging indicator of pandemic trends, remain low across California but are expected to trend up over the next month, according to CalCat projections from the California Department of Public Health.
For the first time since February, the CDC predicted that the number of newly reported COVID-19 deaths will likely increase over the next four weeks, with 1,600 to 4,600 new deaths nationwide likely reported in the week ending May 28.
Bay Area health officials are hoping increased treatment options and the widespread availability of the antiviral Paxlovid will help stem the tide of new virus-related deaths.
Pharmacies across Marin County received about 500 doses of Paxlovid last week, county health officer Dr. Matt Willis said in a briefing Wednesday.
“It happened with little fanfare, but it’s a key milestone in our pandemic response,” he said. “It basically means for the first time since the beginning of the pandemic we have enough medications in Marin to effectively treat everyone who should be treated for COVID-19.”
Willis said that while the county is highly vaccinated, the shots “aren’t 100%” and Paxlovid reduces severe outcomes by 90%.
“For the first time we can visualize a community with zero COVID deaths,” he said, noting that that would have been “unimaginable” last year and calling the treatments a game-changer.
But Willis cautioned that the treatments are recommended only for individuals at high risk for severe outcomes from COVID-19. Starting next week, Marin County will open three new “test-to-treat” sites in Novato, San Rafael and Mill Valley. In a single visit, patients can obtain COVID tests and prescriptions for Paxlovid, if needed.
While case counts do not carry the same weight as earlier in the pandemic, public health experts are concerned that more cases will lead to an increase in long COVID and other virus-related complications, including long-term cardiovascular and neurological issues that could burden health care systems for years to come.
“This is not something you want to get,” Rutherford said. “We know that long COVID can affect people who have even mild symptomatic disease. The way to avoid it is to not get it in the first place.”
Aidin Vaziri (he/him) is a San Francisco Chronicle staff writer. Email: avaziri@sfchronicle.com
