(CNN) Peter McGinn was starting to feel exhausted.
It was his last day in New York. He had an exciting four days meeting in person for the first time with friends he made online during the pandemic. They explored the bustling streets of New York City together and saw anime exhibits at the Anime NYC convention.
"During my time there, I was walking everywhere in New York City. So, I personally just thought that I was just exhausted from doing a lot of walking, not a lot of sleep, eating pretty poorly," McGinn said. "I thought that was all just catching up to me."
McGinn didn't think twice about his fatigue until he returned home to Minnesota on November 22. Later that day he received a group text from someone he spent time with in New York. They texted to the group that they had Covid-19.
McGinn took a rapid at-home test the next day. He tested positive.
"I had such mild symptoms." McGinn said. "If it wasn't for somebody in my party alerting me that they tested positive, I honestly would have thought I had a cold."
McGinn's Covid-19 diagnosis was confirmed with a PCR test and lab results revealed that he was infected with the newly identified Omicron coronavirus variant.
He now wants to be a "resource" for the public and public health, and emphasizes that if he wasn't fully vaccinated with the Johnson & Johnson coronavirus vaccine and boosted with a Moderna booster dose that he could have had a more severe illness.
"The main reason why I wanted to speak out and be a resource was because of the unknown of the new variant," McGinn said. "I've been working with the Minnesota Department of Health in terms of contact tracing with the contacts I was with in New York City."
Among the 30 people that McGinn said he spent time with in New York, 15 total -- including him -- tested positive for Covid-19, and they all had mild symptoms except for one who McGinn said "had a bad day" but did not require hospitalization.
Only one person, other than McGinn, has been confirmed to be infected with the Omicron variant, but McGinn said that when he spoke with health officials they told him it's overwhelmingly likely that everyone who tested positive probably was infected with Omicron.
The US Centers for Disease Control and Prevention has contacted more than 35,000 people so far who attended a recent anime convention in New York.
The agency is encouraging these anime enthusiasts to get tested for Covid-19.
The CDC has joined investigations into the possible spread of the Omicron coronavirus variant at the Anime NYC 2021 convention held last month, assisting with contact tracing among the tens of thousands of convention attendees, CDC Director Dr. Rochelle Walensky said during a virtual White House briefing Tuesday. The convention took place at the Javits Center from November 18-22.
These contact tracing efforts -- arguably the largest in the nation to involve Omicron -- could hold clues to just how easily and quickly this variant may spread.
"Of the reported 53,000 people who attended that conference, more than 35,000 and counting have been contacted to encourage testing for all attendees," Walensky said. "Data from this investigation will likely provide some of the earliest looks in this country on the transmissibility of the variant."
The Minnesota Department of Health announced last week that it had identified the nation's second Covid-19 case caused by Omicron in a resident who recently traveled to New York City and attended the Anime NYC 2021 convention from November 19-21. The United States' first case, also announced last week, was identified in California and health officials expect to find more cases of the variant as genetic sequencing continues around the country.
"Most recently, CDC is assisting both the Minnesota and New York City Health Departments with the investigation among attendees at a recent Anime New York City Convention and has now contacted all 50 states, Puerto Rico and Washington, DC, and 27 other countries with residents who attended to inform them of this ongoing investigation," Walensky said Tuesday.
Last week, following the identification of the Omicron variant in the Minnesota man who traveled to New York City and attended the anime convention, NYC Mayor Bill de Blasio encouraged attendees to get tested for Covid-19 as quickly as possible.
"We should assume there is community spread of the variant in our city," de Blasio said in a statement at the time. He added that the conference required masks and vaccination.
McGinn said that he felt safe at the conference -- and about 99.9% of people he saw kept their masks on -- but he added that the convention only required people to complete at least one dose of a Covid-19 vaccine. The convention's website notes, "You can attend immediately after your first dose."
McGinn, who said he would attend the convention again, said that next time he hopes the event requires attendees to be fully vaccinated, meaning they must be two weeks from having completed two doses of either the Pfizer or Moderna vaccines or one dose of the Johnson & Johnson vaccine.
The organizers behind the Anime NYC convention wrote in a statement last week that they are "actively working with officials from the New York City Department of Health."
The organizers noted that all convention attendees should receive emails or phone calls from either their local health departments or the NYC Test and Trace Corps, which conducts testing and contact tracing, with further information.