Dozens of people aboard a Royal Caribbean International cruise ship tested positive for the coronavirus after it set sail from Fort Lauderdale, Florida, on Saturday, according to the cruise line.

Fifty-five fully vaccinated passengers and crew members on the ship, the Odyssey of the Seas, tested positive, the cruise line said in a statement today, noting that the number represented 1.1% of those on board.

The ship, which was on an eight-night cruise, will not sail to Curacao and Aruba as planned and will remain at sea until it returns to Fort Lauderdale on Sunday, Royal Caribbean said.

“The decision was made together with the islands out of an abundance of caution due to the current trend of COVID-19 cases in the destinations’ communities as well as crew and guests testing positive on board,” the company said. All of the people on the ship who tested positive “are fully vaccinated and mildly symptomatic or asymptomatic,” the cruise line added.

The Odyssey of the Seas, one of Royal Caribbean’s newest ships, made its maiden voyage in July. It can carry more than 5,500 guests and more than 1,600 crew members.

The health episode was reported shortly after a similar one on another Royal Caribbean ship, the Symphony of the Seas. The cruise line said this week that 48 people on that ship tested positive for COVID-19 after it set sail from Miami on Dec. 11. The ship returned to port in Miami on Dec. 18 after a seven-night Caribbean cruise.

Those cases were identified because of contact tracing after a guest tested positive, the cruise line said, adding that 95% of the passengers aboard the Symphony of the Seas were fully vaccinated against COVID-19 and 98% of the people who tested positive were fully vaccinated.

Royal Caribbean requires travelers 12 and older to be fully vaccinated against COVID-19 and to test negative before boarding. Younger children who are not vaccinated must provide a negative PCR test result before sailing and test negative at the terminal before boarding.

The company said that all of its crew members were fully vaccinated against COVID-19 and were tested weekly.

At the beginning of the pandemic in 2020, outbreaks on cruise ships sickened people and upended the tourism industry.

Since the cruise industry restarted operations in the United States this June, efforts to keep the coronavirus at bay have been largely successful. Most companies require full vaccination for crew members and most passengers, and they put strict health and safety protocols in place.

But as the highly contagious omicron variant drives up coronavirus cases in much of the United States and Europe, and criticism of cruise lines has mounted over a lack of transparency in reporting positive cases to passengers and crew members, many lines have adjusted their rules for masking, testing and vaccines.

This article originally appeared in The New York Times.