Cases of omicron subvariant detected in Pitkin County
Major U.S. surge in cases not expected, federal health officials say
The rapidly spreading BA.2 omicron subvariant was detected in both people and wastewater last month in Pitkin County, an official said Thursday.
The subvariant, which is more transmissible than omicron, was declared the dominant COVID-19 strain in the United States earlier this week by the Centers for Disease Control and Prevention, though federal health officials have said they don’t expect a major U.S. surge in cases.
“It’s hard to know if it’s the dominant strain in Pitkin County (yet),” said Josh Vance, county epidemiologist. “Right now, it appears from the data that it’s about half and half (with the original omicron strain).”
Four people who tested positive for COVID-19 between March 3 and March 10 in Pitkin County later were found to be infected with the BA.2 strain when the samples were analyzed by the Colorado state public health department lab, Vance said.
A wastewater sample taken from the Aspen area March 17 also tested positive for BA.2. However, a subsequent wastewater sample taken March 24 contained such low levels of COVID-19, the lab was unable to assess if BA.2 was present, Vance said.
On Tuesday, the CDC estimated that nearly 55% of new U.S. COVID-19 cases the week before were positive for BA.2, with the main concentration coming in the Northeast. While the subvariant — which is distinguished by eight different mutations from omicron — is more contagious, it hasn’t been found to cause more serious cases of the disease.
Pitkin County averaged about two-and-a-half new COVID-19 cases a day for the seven-day period that ended Monday, according to Vance and the county’s online COVID-19 dashboard. That translated into an incidence rate of between about 90 and 95 per 100,000 people, he said.
“I know two-and-a-half doesn’t sound like a lot,” Vance said. “But we still have the third-highest (incidence) level in the state. We still have significant levels of the virus in the community.”
That third-highest rate, however, may be somewhat misleading in that Pitkin County also has one of the highest testing rates in the state.
“If testing was equal among all counties, we probably wouldn’t fall at the top,” he said.
Aspen Valley Hospital received two COVID-19 patients in need of hospitalization in the past two weeks, one on March 15 and one on March 24, Vance said. He did not yet know if either patient had the BA.2 subvariant.
As of Thursday, AVH had no COVID-19 patients, said Jennifer Slaughter, hospital spokeswoman.
The CDC said Tuesday that immunocompromised people and residents over the age of 50 who received a booster at least four months ago were eligible for another booster shot of the mRNA vaccines. Vance said Thursday that appointments remain available in the county for those boosters, and that Pitkin County Public Health encourages those in the affected groups to get the second booster shot.