Four were reported in New York City and one in Suffolk County, Gov. Kathy Hochul said at a Thursday evening news conference.
Officials say two of the cases are in Queens and one is in Brooklyn. The exact location of the fourth case in New York City is unknown at this time, but Hochul says that person lives in the city and is a "suspected traveler case."
The case in Suffolk County is a 67-year-old woman who tested positive on Nov. 30, five days after returning from a trip to South Africa. Officials say she had at least one dose of a COVID-19 vaccine.
"[She] had symptoms, mild symptoms, of a headache and a cough. There is some vaccination history. We don't know if it's one vaccination, two or a booster shot. That information will be shared with the public as soon as we receive it, but there's at least one vaccination involved," Hochul said.
The vaccination statuses of the other four individuals are unknown at this time.
Officials say the individuals are "appropriately isolated at home."
"While this may be highly transmissible, at least from the early evidence, and more information is still forthcoming, we want people to know that the early cases... are not life-threatening. They seem to be minor cases and that is a source of good news for us right now," Hochul said.
"Our testing and trace team is out there immediately working with each individual who was affected to figure out who else they came in contact with," Mayor Bill de Blasio said.
A Minnesota resident who recently attended the Anime NYC convention at the Javits Center also tested positive for Omicron and experienced mild symptoms.
The three-day event drew 53,000 people to New York City. Organizers required attendees to have at least one dose of a COVID-19 vaccine, which aligns with city standards for indoor activities.
While some question if that policy will change to require full vaccination, Hochul says for now, "We're not changing our protocols."
WATCH: Gov. Kathy Hochul, Mayor Bill De Blasio Announce Omicron Cases Confirmed In New York --
Officials are urging everyone who attended Anime NYC to get tested, wear masks and take precautions like social distancing.
A spokesperson for the convention released the following statement --
"On December 2, we were notified that a visitor to Anime NYC tested positive for the new omicron variant of COVID-19. We have confirmed with New York's health officials that the event followed all guidance laid out by the city and state, including mask requirements and proof of vaccination for all individuals inside the Javits Center. According to the Minnesota Department of Health, the visitor developed mild symptoms on November 22, was tested on November 24, and their symptoms have since resolved. We are working actively with New York City health officials, who recommend anyone who attended Anime NYC get tested."
The spokesperson could not confirm how many days the individual attended the convention.
David Crownson was among the thousands at the convention.
"It was really crowded," he told CBS2's Cory James. "And there were people who were just kind of out there with no masks ... I'm getting tested just to alleviate the stress for myself."
Bill Lei, the owner of the book shop Anime Castle, was also in attendance.
"I have both of my vaccination shots, so did my staff, so hopefully that will, you know, mitigate the risk," he said.
"We do anticipate there will be more cases, but to the extent that they are mild, we'll address them. This is not cause for alarm. Again, it was foreseen ever since it was first reported out of South Africa," said Hochul.
"I want all New Yorkers to know that their state government, in collaboration with our local governments, our cities and our counties, are prepared for this," she added.
Hochul, de Blasio and New York City Health Commissioner Dr. Dave Chokshi continue to urge New Yorkers to get vaccinated.
"We have a massive vaccination apparatus and that is by far our best capacity to protect everyone against this variant or any other form of COVID," de Blasio said.
"Beyond that, masking and testing are important," said Chokshi. "There are common sense precautions that we have seen have worked over the past two years. Stay home if you're not feeling well, that includes mild symptoms... Hand washing, particularly important right now, as well."
"It starts on the foundation of vaccination. New York City is in a good place, but we have to drive even further," Chokshi added.
This news comes on the heels of de Blasio announcing the city is imposing a vaccine mandate on employees of private schools, including Catholic schools and yeshivas.
The country's first case of Omicron was confirmed in California on Wednesday.
Officials repeatedly warned that the new mutation would inevitably arrive in the Tri-State Area.
Though doctors are only to beginning to learn about the Omicron variant, they have said it could be highly transmissible. It reportedly first surfaced in Europe before being confirmed in South Africa.
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