(CNN) — Two guests aboard the first major sea cruise hosting Americans since the pandemic halted the industry have tested positive for coronavirus in required end-of-cruise testing, the cruise line said Thursday.
The two guests, who shared a stateroom on the seven-day Celebrity Millennium cruise from St. Maarten, are asymptomatic, in isolation and being monitored by a medical team, Celebrity Cruise Lines said in a news release.
The retest results for close contacts of the two passengers have come back negative, Royal Caribbean Group said Friday. Royal Caribbean is the parent company of Celebrity Cruises.
When the ship returns to St. Maarten on Saturday, Celebrity will provide private transportation home for the two passengers, according to Royal Caribbean Group.
The ship set sail Saturday "with fully vaccinated crew and guests and following comprehensive protocols that align with our destination partners and exceed CDC guidelines to protect the health and safety of our guests," the release said.
Fully vaccinated people are more than 90% protected against infection, with partially vaccinated people 81% less likely to become infected than those who haven't had been inoculated, according to the ongoing study of essential workers who got Pfizer/BioNTech's or Moderna's vaccine.
Those in the study who got breakthrough infections after one or two doses had 40% less virus in their bodies and were 58% less likely to have fever. They spent two fewer days in bed than unvaccinated Covid-19 patients.
Guests had to show negative Covid-19 tests
All guests aboard the Celebrity Millennium cruise — with port stops in Barbados, Aruba and Curacao — were required to show vaccination proof and a negative Covid-19 test within 72 hours of departing St. Maarten on Saturday, the release said.
About 500 passengers were on board, with more than 95% fully vaccinated. Children who could not yet receive vaccinations were required to show negative Covid-19 tests.
Details of the two Covid-positive passengers' vaccinations were not immediately known.
"This situation demonstrates that our rigorous health and safety protocols work to protect our crew, guests and the communities we visit," the news release said.
The Royal Caribbean Group, the parent company of Celebrity Cruise Lines, said Monday that returning to Barbados "for the first time in over a year is truly special."
"Every measured step was taken to ensure that we protect the health and safety of our guests, crew and the residents of this treasured destination and we are thankful," its Twitter post said.
CNN's Maggie Fox contributed to this report.