Cruise operator Royal Caribbean said on Thursday two guests onboard its Celebrity Millennium ship have tested positive for COVID-19, but are asymptomatic and currently in isolation.
The guests, who were sharing a room, are being monitored by the company's medical team, the cruise operator said, adding that it was conducting contact tracing, expediting testing for all close contacts of the individuals.
Celebrity Millennium was one of the first cruises in North America to restart sailing last week, after more than a year.
Royal Caribbean started sailing in June after meeting the Centers for Disease Control and Prevention's comprehensive guidelines that included a fully vaccinated crew and everyone over 16 presenting proof of vaccination against COVID-19.
Cruise operators are among the last to return to their pre-pandemic operations as the CDC laid out strict guidance earlier this year for the cruise industry for resuming trips, after some ships became hotbeds for the virus last year.