Sonoma County keeping COVID-19 variants in check
In the battle for dominance between coronavirus variants, Sonoma County and the entire state of California apparently have come upon good fortune, after more than a year with plenty of pandemic pain.
The county certainly isn’t guaranteed this positive phase will continue, so infectious disease experts say it’s imperative to keep aggressively vaccinating the local population.
Here’s what’s been occurring: The dominant COVID-19 strain in Sonoma County and around the state is a homegrown West Coast variant mutation that is for now “out-competing” other more contagious and deadlier variants, playing crucial interference that could be preventing these other strains from taking hold, said Dr. John Swartzberg, a UC Berkeley infectious disease expert.
And this tamer variant does not appear to be causing another surge of virus infections, according to Swartzberg and other medical experts.
In other parts of the United States, coronavirus strains like the South African, Brazilian and U.K. variants have taken hold and triggered a spring surge of new COVID-19 cases. But in California, that’s not the case. At least not yet.
In short, California has gotten lucky, said Dr. George Rutherford, an infectious disease epidemiologist at UC San Francisco.
“We did not engineer this. It just happened,” Rutherford said. “Whether it was our wonderful weather or our great population or whatever, I don’t know. But for whatever reason (the West Coast variant) appears to have a selective advantage — for now. This could change.“
A future examination of the molecular biology of variants eventually will yield the reasons why some strains became dominant in some parts of the country over others.
“For right now, the observation is that we’re seeing more cases of the West Coast variant and fewer cases of the U.K. variant than in the rest of the country, and buy a lot,“ Rutherford said.
The West Coast or California variant appears to have contributed to a sort of pandemic pause, opening a window of opportunity, Swartzberg said. It’s a chance to get more people vaccinated and continue to keep transmission low to prevent a more deadly homegrown mutation from popping up, he said.
“We need to take advantage of this pause that we’re experiencing,” Swartzberg said. “Every human being who is not immune and gets infected is a viral factory ... so now is the time to get on top of this, while we can.”
Virus hospitalization low
The pandemic outlook continues to improve in Sonoma County since the winter surge. The county is in the orange stage of the state’s community reopening plan, the second least restrictive part characterized by a moderate rate of virus transmission.
According to the state’s most recent assessment of local COVID-19 metrics, the county is seeing 3.9 new daily virus cases per 100,000 people. Test positivity, the share of COVID-19 tests that turn up positive, is only 1.6% and that rate in the county’s most disadvantaged communities is 1.9%
Local health officials say the ongoing vaccination effort, with 38% of eligible adults now fully inoculated and 19% partially vaccinated, is helping keep the virus in check. Officials point to the vaccination rates in area skilled nursing and assisted living centers as a prime example of the success of the three vaccines on the market nationwide.
About 95% of all residents and 85% of staff in senior care homes in the county have been fully vaccinated. As a result, there have been no new COVID-19 infections among senior care home residents since March 5 and no deaths at those properties since Feb. 16.
What’s more, coronavirus hospitalization rates for people 65 and older went into a free fall about six weeks after the local vaccination effort started in late December. Throughout the pandemic that began in March 2020, virus-related hospitalization rates for seniors have been sharply higher than they’ve been for residents younger than 65.
During the winter surge, hospitalization levels for county residents 65 and older were between 4 and 5 individuals per 100,000 local residents, compared to between 1 and 2 per 100,000 people younger than 65. Now, the rates for both groups are about the same, at well below 1 per 100,000.
In California, the so-called West Coast variant — which is actually made up of two closely related strains B.1.427 and B.1.429 — appears to be prevailing sevenfold over the next most prolific strain, the U.K. variant. State health officials have genetically sequenced 13,490 cases of West Coast variants statewide, compared to 1,937 cases of the U.K. variant, according to the latest California public health data on COVID-19 variant cases.