Omicron comprises more than 90% of new COVID-19 infections in Colorado

By: - December 29, 2021 3:35 pm

A Centers for Disease Control and Prevention scientist was prepares to test a patient’s sample for SARS-CoV-2. (CDC)

The omicron variant of COVID-19 comprises at least 91% of new infections in Colorado, Gov. Jared Polis said at a virtual news conference Wednesday. That estimate, based on laboratory analysis, is up from 1% just two weeks ago — showing how quickly the variant is spreading in the state.

“If you get COVID, there’s a very high chance that it’s omicron variant right now,” Polis said.

Against the backdrop of a rapid increase in infections across the U.S., the Centers for Disease Control and Prevention released new guidelines on quarantine and isolation, which the Colorado Department of Public Health and Environment adopted Monday. The guidelines call for a five-day isolation period, down from 10 days, for people who test positive for COVID-19 but don’t have symptoms.

Dr. Eric France, the state’s chief medical officer, said the new federal guidelines make sense because of the shorter incubation time for the omicron variant as compared with earlier variants of COVID-19.

If you’d been exposed to the alpha variant at a Christmas party, France said, symptoms would occur six to seven days later, around New Year’s Eve. For the delta variant, the symptoms would show up about four days after exposure. But with omicron, the incubation period is as short as one to three days.

“If I was exposed to omicron on Christmas Day, I likely would have had my symptoms on Tuesday,” France said.

An average of 4,140 new cases of COVID-19 were reported each day in Colorado from Dec. 21 through Dec. 27, according to data from CDPHE. That’s more than double the previous week’s daily average of 1,931 new cases. Approximately 14% of tests are coming back positive — a sharp increase in the positivity rate that suggests many cases are going undetected.

Polis, a Democrat, touted Colorado’s 150 free community testing sites across the state, many of which also offer vaccines. A few of those sites include:


Colorado Springs:


Fort Collins:

  • Timberline Church, 2908 S. Timberline Road; Monday through Friday; 8 a.m. to 6 p.m.


Colorado also offers free, rapid, at-home COVID-19 tests to people who request them online.

Editor’s note: This story was updated at 9:45 a.m. Dec. 30, 2021, with updated case data from CDPHE.

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Faith Miller
Faith Miller

Reporter Faith Miller covers the Colorado Legislature, immigration and other stories for Colorado Newsline.