Yolo County is now seeing a post-Thanksgiving increase in its COVID-19 case and test positivity rates, though hospitalizations remain low.
The county’s case rate was about seven per 100,000 residents on Thanksgiving day but has since risen to 8.4 and is expected to rise further in the coming days.
Health Officer Dr. Aimee Sisson called the increase in cases unsurprising given the Thanksgiving holiday and its associated travel and gatherings.
“The timing of this increase is nearly two weeks after the Thanksgiving holiday, which is what we’ve seen with previous increases in COVID-19 case rates after major holidays,” Sisson told the Yolo County Board of Supervisors on Tuesday.
She added that “the recent increase is small and could be chocked up to day-to-day variability.
However, she said, the expectation is that cases will continue to increase for the next several days, “in fact, making it a trend.”
The county does remain in the orange tier of the Centers for Disease Control and Prevention’s color-coded community transmission chart, where red marks the highest transmission category with more than 100 cases per 100,000 residents in the past seven days and orange indicates 50 to 99 cases.
As of Tuesday, Yolo County’s rate was 59.
The county’s test positivity rate is also rising, “from 0.7 percent to 0.9 percent over one day, representing a relative increase of nearly 30 percent,” Sisson said.
Hospitalizations — and deaths — are lagging indicators, coming weeks after a rise in cases, “so we have not yet seen an increase in hospitalizations in Yolo County,” Sisson said.
In fact, hospitalizations have declined from eight COVID-19 patients in the county’s two hospitals on Nov. 22 to five as of Tuesday, none of whom are in intensive care.
Sisson apologized Tuesday to anyone who got caught up in a MyTurn vaccine scheduling snafu over the weekend.
A number of county residents reported they showed up for a clinic in Woodland that they’d registered for on MyTurn only to find there was no clinic.
“Our team has been experiencing several challenges with the state’s MyTurn registration system recently,” Sisson said. “Glitches in MyTurn resulted in the inadvertent creation of clinics that were not visible to staff but were visible to members of the public who signed up for appointments, only to show up to find no clinic.”
Sisson said she believes the problem on MyTurn — one that other counties experienced as well — as been resolved and everyone who signed up for a “phantom clinic,” as she described them, has been contacted to reschedule.
The UC Davis Genome Center has yet to report a local case of the Omicron variant but continues to sequence every positive sample received via Healthy Davis Together, Healthy Yolo Together and campus testing.
Sisson said Tuesday that she expects much more will be known about Omicron in the coming weeks, “but right now we simply don’t know much.”
Yet to be determined are how infectious Omicron is, how effective vaccines and existing treatments are against it and whether Omicron causes more severe disease.
What is known comes from South Africa’s findings, Sisson noted.
“South Africa is experiencing rapid… growth in cases during its current wave, with cases rising faster than in all three previous waves, including the Delta wave.
“This rapid spread suggests a virus that is either more contagious or is escaping immune responses or both.”
Sisson said that cases of Omicron in South Africa are occurring among people previously infected with the virus that causes COVID-19 and “these reinfections suggest that Omicron can evade immunity from prior infection.”
The Omicron wave in South Africa is also resulting in higher hospitalizations for younger South Africans, especially children under the age of five, Sisson said.
“It’s not known how any of these findings from South African will translate to the United States, where vaccination rates are higher and the population is older,” she said. “Only time will tell.”
Until then, “we should focus our efforts on fighting the variant that is already here — Delta — and preparing for the variant that is coming — Omicron.