The first case was detected in California, the agency said Wednesday. The individual recently returned from South Africa, where the variant has been found in many new cases.
COVID-19 cases with the Omicron variant have now been found in multiple states, according to media reports.
The first confirmed case of the Omicron variant was found in California, the U.S. Centers for Disease Control and Prevention said Wednesday.
Five cases have been confirmed in New York City, the Associated Press reported Friday.
On Friday, a case was confirmed in Philadelphia, Pa., according to the city's health department. Cases have also been found in Minnesota Colorado, and Hawaii, the Associated Press reported. The Minnesota resident had recently been in New York City for an anime convention, according to the AP and other media reports.
Five cases have been confirmed in New York City, the Associated Press reported Friday.
The individual has recently returned from travel to South Africa, where the Omicron variant has been found in many new cases of the coronavirus. The individual has experienced mild symptoms and has been self-quarantining, the CDC said.
The individual, who was not identified, was fully vaccinated.
The Omicron variant of COVID-19 has emerged as a new threat in the pandemic because it appears to be transmitted very easily, health officials said. The World Health Organization classified it as a variant of concern Nov. 26. The U.S. followed with a similar designation on Nov. 30.
More than two dozen countries have confirmed the Omicron variant, according to The New York Times. South African researchers first identified the variant in late November.
Federal health officials have urged Americans to get vaccinated if they haven't already done so. Those who have been vaccinated should get booster shots as soon as possible, officials said.
The Delta variant remains the most dominant coronavirus strain in the U.S., the CDC said.
The WHO said it's not yet clear if the Omicron variant is more transmissible than other forms of the coronavirus, though the agency said new cases are rising in areas where the Omicron variant has been found. The WHO said there's no information yet to confirm if symptoms associated with the Omicron variant are different or more severe than other variants.
Researchers are working to understand the effectiveness of current vaccines against Omicron.
Earlier this week, Biden told Americans the Omicron variant is "a cause for concern, not a cause for panic."
The Biden administration is looking at stricter COVID-19 testing requirements for those traveling to the United States, The Washington Post reported.
To date, there have been more than 48 million coronavirus cases reported in the United States and more than 780,000 deaths have been tied to COVID-19.
This story has been updated from an earlier version.