Officials with the Colorado Department of Public Health and Environment (CDPHE) on Thursday announced they had detected the state’s first case of the omicron variant of COVID-19. 

What You Need To Know

  • Officials with the Colorado Department of Public Health and Environment (CDPHE) identified the state's first case of the omicron variant of COVID-19 on Thursday

  • It was the third case of the omicron strain detected so far in the U.S.; the first case was reported in California, the second in Minnesota and more were announced in New York late Thursday

  • The Colorado case was identified in a fully-vaccinated adult woman who returned to her home southeast of Denver after traveling to several countries in Southern Africa

  • The woman was experiencing mild symptoms and quarantining at home; all close contacts had so far tested negative for COVID-19

The case was identified in a fully-vaccinated woman who lives southeast of Denver, after she returned stateside from traveling to several countries in Southern Africa for tourism. Officials said she was eligible for a booster but had not yet received her third shot. 

She returned from her travels late last week, and she tested positive for COVID-19 several days after. 

The patient was experiencing mild symptoms and quarantining at home. All close contacts had so far tested negative for COVID-19.

“This case consistently followed public health recommendations, including the use of a mask during travel,” Dr. Rachel Herlihy, Colorado State epidemiologist, said during an afternoon press conference. “We are certainly grateful to her and to all Coloradans that continue to follow public health recommendations, including mask use.”

Herlihy added that officials have “no reason to believe” that masks are less effective against the omicron variant than other strains of COVID-19 at this point. 

It was the third case of the omicron strain detected in the U.S. Hours later, New York City detected at least five cases of omicron -- earlier Thursday, officials from the Minnesota Department of Health reported an individual tested positive following travel to New York City. 

New York City mayor Bill de Blasio had said New Yorkers "should assume there is community spread of the variant in our city."

Officials in California on Wednesday said they discovered the first known omicron infection in the U.S. That person had recently traveled to South Africa, where the variant was first sequenced. 

Colorado’s Gov. Jared Polis, a Democrat, said Thursday it “wasn’t a matter of if, it was a matter of when” the omicron variant would be identified in the state. 

“We have travelers that returned from Southern Africa. We don't yet have substantial community transmission of the virus,” Polis said, adding that all Coloradans should get vaccinated or get a booster shot if they are eligible. 

Health experts do not yet know much about the nature of the omicron variant, other than that it has more mutations than previous strains. Scientists are awaiting more data to know whether the variant might be more transmissible or cause more severe illness than previously-identified variants of COVID-19.

This story was updated to include quotes from Colorado state officials; it was also updated to include new cases of the omicron variant that were detected in New York.