Nevada County has identified its first case of the BA.2 variant, after a COVID-19 specimen from the week of Feb. 22 was sequenced, county Deputy Public Health Officer Dr. Glennah Trochet said Wednesday.

The BA.2 strain, a descendant of the Omicron variant, was gaining prevalence as of late February and causing more than a third of new Omicron cases worldwide at the time, the Associated Press reported.

In an email Wednesday, Trochet wrote that 25 specimens collected at Nevada County’s OptumServe testing sites are selected at random each week to be “run for whole-genome sequencing” for the purpose of tracking variants.

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Of the 25 specimens sequenced from the week of Feb. 22, one was the BA.2 variant, while the other 24 were BA.1.

Officials have previously said that there is some delay between a variant’s arrival in the area and its detection, given the amount of time needed for sequencing.

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“The fact that BA.2 was detected tells us that the variant is circulating here as it has been in the region for some time, and we know that this variant is slowly increasing in California,” said Trochet.

County Public Health Officer Dr. Sherilynn Cooke said last Wednesday that BA.2 had not been identified in the county at that point, but that it had been in neighboring counties and was “something we’re keeping our eye on.”

She said last week that that BA.2 was more transmissible than the original Omicron variant, and that it was unknown at that point to what extent having contracted the original Omicron variant would provide protection against BA.2.

“It definitely is more contagious than BA.1, Omicron Type 1, but it doesn’t seem to cause more severe disease,” she said of the new variant. “But, again, just as Omicron didn’t cause more severe disease than Delta, but it was so much more infectious that it spread everywhere … that is the concern about the BA.2 variant.”

CONTINUED DECREASE

As of Thursday, according to state data tracking COVID-19, Nevada County had an average daily case rate, per 100,000 residents, of 8.1 cases.

This average is approximately half the rate the county had as of last Wednesday — 17.1.

At the time, county Director of Health and Human Services Ryan Gruver had described that case rate as “still at nearly double what would have put us in the purple tier under the state’s Blueprint for a Safer Economy,” although significantly improved from the Omicron surge’s late January peak.

Dipping under 10 this week, the county has returned to a case rate which would not have qualified it for the most restrictive tier. It had not been in this single-digit range since summer 2021, prior to the surge fueled by the Delta variant.

The county also, as of Thursday, had a test positivity rate of 3.6%, down from a rate of 6.4% as of last Wednesday — and over 25% during the surge’s peak in January.

According to the Centers for Disease Control and Prevention’s tracking of community levels of COVID-19, Nevada County was at a “medium” level as of Thursday.

The agency’s recommendations at this level are to “stay up to date with COVID-19 vaccines,” get tested if experiencing symptoms, and that those who are at high risk for severe illness consult with a health care provider about masking and other precautions.

Victoria Penate is a staff writer with The Union, a sister publication of the Sierra Sun. She can be reached at vpenate@theunion.com