Dec 2 (Reuters) - New York has confirmed five cases of the Omicron coronavirus variant, its governor said on Thursday, bringing to five the number of U.S. states having detected the variant, with 10 reported infections nationwide. California, Colorado and Minnesota have found cases of the coronavirus variant among patients who were fully vaccinated and developed mild symptoms, while Hawaii reported a case with an unvaccinated person, who had moderate symptoms.New York Governor Kathy Hochul told a news conference one of the state"s the cases involved a 67-year-old Long Island woman with mild symptoms of a headache and cough who had recently returned from South Africa. The woman tested negative upon return on Nov. 25 but tested positive for the coronavirus on Tuesday, and her results were sent to a lab for further examination. She had "some vaccination history" but it wasn"t yet clear if she had received one or two doses or a booster shot, Hochul said. The other four people were New York City residents but further information was not yet available, the governor said. No cause for alarm," Hochul said. "We don"t have more information at this time but we suspect there will be more cases emerging, and the best thing everyone can do is to realize we are not defenseless against this variant at all, that vaccines, we know, are going to ensure there is less severe symptoms." The Minnesota patient is the first known U.S. case of community transmission of the Omicron variant, found in a fully vaccinated man who had recently traveled to New York City and attended a conference. Hawaii on Thursday also confirmed a case of community spread. The infected person, who had no history of travel, had previously had COVID-19, the Department of Health said. To combat the spread of Omicron, President Joe Biden on Thursday announced new testing requirements for international travelers and promised in the coming weeks that Americans would have access to free, rapid at-home COVID-19 testing. Colorado health officials on Thursday said a woman with the Omicron variant had recently returned from a trip to southern Africa. California on Wednesday reported the first U.S. case of the variant in a fully vaccinated traveler who had been in South Africa. Los Angeles County on Thursday confirmed California"s second case of the variant. After determining the Minnesota case had a New York connection - the man attended an anime convention at New York City"s Javits Center from Nov. 19 to 21 - health officials immediately activated the "Test and Trace Corps" to contact conference attendees in an effort to contain the spread, said Mayor Bill de Blasio. “We are aware of a case of the Omicron variant identified in Minnesota that is associated with travel to a conference in New York City, and we should assume there is community spread of the variant in our city," the mayor said in a statement. "MANY MORE CASES TO COME" Dr. Leana Wen, a public health professor at George Washington University and former Baltimore health commissioner, said it was only a matter of time before more Omicron cases are detected in the United States. The Minnesota case "means that there is spread in the United States. There will be many more cases to come," Wen said on Twitter. Scientists are investigating Omicron, which has been labeled as a variant of concern by the World Health Organization, to see if it is more transmissible than the Delta variant that is now prevalent and if it causes more severe disease. They are also studying how well current vaccines work against it. Minnesota Governor Tim Walz said the news of the case in the state was "concerning, but it is not a surprise," adding that "We know that this virus is highly infectious and moves quickly throughout the world." Walz urged residents to get vaccinated and wear masks indoors. The best response to the new variant is the same as it"s been throughout the pandemic: get a COVID-19 shot, he said. About 60% of the total U.S. population, or 196 million people, have been fully vaccinated, one of the lowest rates among wealthy nations. More than 786,000 people have died from COVID-19 in the United States, including 37,000 in November alone.