NEW YORK — When a person tested positive for omicron after attending an anime convention in New York City late last year, health officials raced to determine if the indoor gathering was a superspreader event.

It wasn’t, the U.S. Centers for Disease Control and Prevention concluded Thursday. Widespread masking, vaccinations and good air flow at the Javits Center prevented the highly contagious omicron variant from spreading widely.

Investigators found 119 infections from about 53,000 people who attended the event over three days in November.

A Minnesota man at the Anime NYC convention became one of the first Americans diagnosed with omicron. Omicron spreads more easily than earlier versions of the coronavirus and drove a national surge over the winter.

While omicron cases were found in the man’s small social circle, other cases turned out to be from the older delta variant, the CDC said.

“This large event did not lead to widespread transmission” of omicron, the investigators wrote in one of the two studies published by the CDC.

The Minnesota man was fully vaccinated and had gotten a booster. While in New York, he stayed in a vacation rental with three other attendees and was in close contact with about 30 people during a five-day visit.

Sixteen of the man’s close contacts got infected. All were vaccinated and no one was hospitalized or died, investigators said.