The COVID-19 omicron variant was discovered in a Minnesota resident who attended the Anime NYC 2021 conference at the Javits Center in November, marking the first reported instance of the variant in both New York City and New York state.

The CDC reported on Thursday that it was investigating a confirmed COVID-19 case caused by the omicron variant after a Minnesota resident returned to their home state and tested positive after attending the annual anime convention, which was held this year from Nov. 19-21. According to the CDC, the person, who has since recovered, began experiencing minor symptoms on November 22 and was tested on November 24.

Mayor Bill de Blasio said in a statement that the city is "aware of a case of the Omicron variety" that was discovered in Minnesota and has since been linked to the New York City anime convention. "We should presume there is community distribution of the variant in our city," he adds.

The mayor's statement acknowledged that the conference needed masks and that attendees had gotten at least one dose of the Pfizer, Moderna, or Johnson Johnson vaccine, as required by the city's Key2NYC vaccination mandate. On the matter, his office is collaborating with the state, the CDC, and the event organizers at the Javits Center, while the city's test and trace corps is contacting conference attendees. However, anyone who attended the event — "particularly anyone having symptoms" — was asked to get tested and take additional precautions, according to the statement.

The news comes just days after the city issued a new mask advisory on Monday, strongly pushing all citizens, regardless of immunization status, to wear masks in all public indoor settings. New York City health officials made the notification in anticipation of new omicron variant COVID-19 infections in the city.

The mayor noted at a press conference on Monday that the city's choice to not impose an indoor mask rule at this time was due to a wish to preserve the focus on vaccination while the omicron form spread.

The first known case of omicron in the United States, which the World Health Organization has classified as a "variant of concern," was reported on Wednesday after a vaccinated traveler returned to California from South Africa on Nov. 22 and developed mild symptoms before testing positive for COVID-19.