Colorado health officials on Thursday reported that the third confirmed U.S. case of the COVID-19 omicron variant has been detected in their state.
The Colorado Department of Public Health and Environment (CDPHE) said in a statement that it has confirmed the first omicron case in Colorado.
“The case was identified in an adult female resident of Arapahoe County who had recently traveled to Southern Africa for tourism,” the CDPHE said. “She is experiencing minor symptoms and is isolated and recuperating at home. She had been fully vaccinated and was eligible for the booster vaccine but had not received it yet.”
Omicron cases have also previously been confirmed in California and Minnesota.
Colorado State Epidemiologist Rachel Herlihy said in a press conference on Thursday that the infected resident had followed public health guidelines when traveling, such as wearing a mask.
According to Herlihy, whole genome sequencing of the the woman’s test was completed Thursday morning. Close contacts of the resident have so far tested negative.
Herlihy told reporters that the infected Colorado resident travelled through numerous countries in Africa and returned to Colorado late last week. At the time of her return, she was not symptomatic.
The Colorado health official noted that mild cases of omicron have been reported anecdotally, but pointed out that these cases appear to have been clustered in younger people who are less likely to develop severe illness due to COVID-19.
The Centers for Disease Control and Prevention (CDC) on Wednesday confirmed the first U.S. case of the omicron variant in California. Like the Colorado woman, the San Francisco resident who tested positive was fully vaccinated and had recently travelled to southern Africa.
In Minnesota, a fully vaccinated adult man was confirmed to have tested positive for the omicron variant on Thursday. The Minnesota man’s mild symptoms had resolved by the time he got tested for COVID-19.
Though no cases of omicron have been confirmed in New York, New York City Mayor Bill de Blasio (D) said on Thursday that people should assume the variant is already present in the city.
“We are aware of a case of the Omicron variant identified in Minnesota that is associated with travel to a conference in New York City, and we should assume there is community spread of the variant in our city,” he said.
Since omicron’s emergence, health experts have stated that it is still unclear how well the strain evades immunity offered by currently available COVID-19 vaccines. Numerous vaccine developers have hypothesized that oral COVID-19 treatments and booster shots should be effective against the variant.
Officials and health experts have said it will take a few weeks of testing before the omicron variant is better understood.
In response to the omicron variant’s spread, the Biden administration has implemented a travel ban on eight African countries where the strain is believed to be prevalent. This measure has been blasted by health officials as being ineffective, though administration officials have argued it will buy time for the U.S. to better prepare for omicron.
Updated at 4:08 p.m.