Celebrity Millennium, which is part of Celebrity Cruises owned by the Royal Caribbean Group, was the first cruise ship to sail out of North America since the coronavirus pandemic began in 2020, Celebrity Cruises said in a news release. "Today two guests sharing a stateroom onboard Celebrity Millennium tested positive for Covid-19 while conducting the required end of cruise testing," the cruise line company said. "The individuals are asymptomatic and currently in isolation and being monitored by our medical team." All guests were required to show a negative Covid-19 test and proof of vaccination 72 hours before its departure on Saturday, the company said.