Updated at 2:56 p.m., Dec. 2, 2021.
Dec. 2, 2021 -- A second U.S. case of COVID-19 caused by the Omicron variant has been picked up by genetic testing in Minnesota.
The man, from the Minneapolis area, fell ill on Nov. 22 after attending the Anime NYC 2021 conference at the Javits Center in New York City a few days before. He was tested on on Nov. 24.
His case was officially confirmed just hours ago, said Jan Malcolm, commissioner of the Minnesota Department of Health, which has one of the strongest COVID-19 testing programs in the U.S. and caught his case.
Minnesota health officials said the man was fully vaccinated and had received a booster in November. He had no recent history of international travel.
So far, one of his close contacts, a person living in Minnesota, has tested positive for COVID-19 using a rapid antigen test. It is not yet known if that person is also infected with the Omicron variant or how severe that person’s symptoms may be.
Disease detectives are focusing on the Anime NYC 2021 convention as the most likely place the man was infected, given the timing of his symptoms, which started the day after the conference ended. The conference, which was held at the Javits Convention Center on Nov. 19-21, attracted 53,000 attendees, according to organizers.
In a statement published on Thursday, New York City Mayor Bill de Blasio said residents should assume there is community spread of the Omicron variant in the city.
He said the city was cooperating with state health investigators and the CDC as well as contact tracers to contact conference attendees.
“Anyone who attended the Anime NYC conference, especially anyone experiencing symptoms, should get tested immediately and take additional precautions, including social distancing,” de Blasio said.
The conference required attendees to get at least one dose of a vaccine and wear a mask. In a statement posted on the event’s website, organizers said people could attend immediately after vaccination. And people could remove their masks to eat and drink and when speaking on panels.
Many photos of conference events posted on Twitter showed people with their masks pulled down, at least for photos. There was little social distancing, though conference organizers said the ventilation system in the Javits Center had been upgraded for safety.
The Minnesota man’s symptoms have cleared up, according to a news release on the case from the Minnesota Department of Health.
He was advised to isolate from others, but it’s unclear if he had contact with anyone else before learning he was infected.
“I just want to reinforce again: Now is especially the time for everyone 5 and older to get vaccinated, and for everyone 18 and older to get their booster when they're due,” Malcolm said.
She said everyone who has symptoms or has been exposed needs to get tested and “to take appropriate action with the results of those tests.”
She also emphasized the importance of wearing well-fitting masks in indoor public settings and in some outdoor settings. “That is all of us, vaccinated or unvaccinated,” she said.
Minnesota officials said they had a small number of samples that had been caught in first-round screens and flagged because they had telltale s-gene target dropouts, which can sometimes be a sign of the Omicron variant. They said they were still waiting for final genetic sequencing results on those samples.
The first case of COVID-19 caused by Omicron was detected Wednesday in California. That case was in a traveler who had recently returned from South Africa.
“We’re going to see more and more domestic cases. This isn’t a surprise,” says Michael Osterholm, PhD, who directs the University of Minnesota’s Center for Infectious Disease Research and Policy. “What it really points out is why we have to get as many people vaccinated as possible and get booster doses all up to date.”