Two passengers from the United States who shared a room on board Celebrity Cruises’ Celebrity Millennium ship, which was billed as carrying “fully vaccinated crew and guests”, have tested positive for COVID-19, the cruise line said in a statement.

The tests came back positive during end-of-cruise testing, which is completed 72 hours before passengers return to the U.S., Celebrity Cruises spokesperson Jonathon Fishman told USA TODAY.

All adult passengers were required to show proof of vaccination in addition to a negative COVID-19 test within a 72-hour period before the ship departed from the Caribbean island of St. Maarten Saturday.

Children under the age of 12 are not yet eligible for COVID-19 vaccinations in the U.S., where the majority of passengers are from. Fishman noted there were fewer than 10 children on board and said no other vaccine exemptions had been granted.

There are more than 1,200 people on board the ship.

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