He or she was fully vaccinated against COVID-19 and experienced only “mild symptoms that are improving,” officials with the Centers for Disease Control and Prevention said.
The patient, who was not named in the CDC’s announcement of the first U.S. case of the Omicron variant Dec. 1, is self-quarantining.
“All close contacts have been contacted and have tested negative,” officials said.
The announcement comes as no surprise to many as the Omicron variant, first identified in South Africa, has been reported in countries around the world in recent days. Hong Kong, the United Kingdom, and Germany each reported this variant, as have Italy and the Netherlands. Over the weekend, the first North American cases were identified in Canada.
Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases, announced over the weekend that this newest variant was likely already in the United States, telling ABC’s This Week its appearance here was “inevitable.”
Similar to previous variants, this new strain likely started circulating in the United States before scientists could do genetic tests to confirm its presence.
The World Health Organization named Omicron a “variant of concern” on Nov. 26, even though much remains unknown about how well it spreads, how severe it can be, and how it may resist vaccines. In the meantime, the United States enacted travel bans from multiple South African countries.
It remains to be seen if Omicron will follow the pattern of the Delta variant, which was first identified in the United States in May and became the dominant strain by July. It’s also possible it will follow the path taken by the Mu variant. Mu emerged in March and April to much concern, only to fizzle out by September because it was unable to compete with the Delta variant.
A version of this article first appeared on WebMD.com.