Test results, case totals and wastewater analysis all show that San Diego County, like much of the country, is experiencing an increase in coronavirus activity. But experts say the trend looks like the typical summer uptick that has occurred, to one extent or another, since COVID-19 arrived in 2020.
In its latest respiratory report released Thursday, the county shows that 8 percent of lab-performed COVID-19 tests came back positive in the first week of June, a number that is about double what it was in May. And the amount of coronavirus material detected at the Point Loma sewage plant has also increased, from an estimate of about 1.9 million copies of viral genetic code in late May to 3.9 million in early June.
But those moves come nowhere near hitting highs set during the COVID-19 pandemic and, thus far, hospitals report that they are taking the increase in stride.
Dr. Craig Uejo, chief quality officer at Scripps Health, said this week that while the organization’s five hospitals do have more patients with COVID-19 admitted, the increase has been a blip.
“We were running in the low single digits for quite a few weeks there since the winter ended, and we’re up to about 16 now,” Uejo said. “So, it’s a slight increase but those numbers would have to be much, much higher to scare us.”
As hospitals are no longer required to report daily COVID-19 patient totals to public health departments, it is not clear whether Scripps’ experience is the case at other providers, though officials with Sharp HealthCare and UC San Diego Health said this week that their admission totals have been essentially flat.
“We have seen an uptick in COVID cases in the community, but hospitalizations have remained low — even lower than this time last year,” said Dr. Chris Longhurst, chief medical officer at UC San Diego Health.
According to the county’s monthly COVID-19 tracking report, the region averaged 58 confirmed COVID-19 cases per day in the first full week of June compared to 25 per day in the first full week of May. That average case volume, noted Dr. Wilma Wooten, the county’s public health officer, is actually slightly lower than it was during the same week — June 2 through June 8, last year. Indeed, county records that track cases by date of symptom onset, show that the county average was 63 cases per day during the same week last year.
“For the past four years we’ve had summer surges of COVID-19 and, while we will have a surge this year, it may not be as high as last year just as last year was not as high as the prior summer’s surge,” Wooten said.
Virologists say a new coronavirus subvariant dubbed PK.3 is driving the current increase in activity due to a fresh set of mutations to its spike protein, the structure on the virus’s surface that controls its ability to enter human cells.
Computational biologist Karthik Gangavarapu, an expert who works with immunologist Kristian Andersen at San Diego’s Scripps Research, noted that just like the subvariants that have caused surges in previous summers, PK.3 is a stepwise evolution of the original Omicron strain that caused the pandemic’s biggest surge in cases in late 2021 and early 2022.
“I think this is what we would expect from a new variant, two mutations primarily in the spike region that are sort of conferring this variant to evade immunity better than the previously, but this is not a dramatic shift,” he said.
This fall’s booster shot, which is still being formulated, he said, is likely to confer significant protection even if the type of virus circulating in the fall is not a perfect match to the genetic fingerprints used to make the vaccine.
The protective antibodies that vaccines cause a person’s immune system to produce, he noted, are not binary. Those that are a close but not perfect match still help.
