SINGAPORE (AP) — An elderly passenger on board a Royal Caribbean “cruise to nowhere” has been diagnosed with the coronavirus, prompting the vessel to return early to Singapore.

Annie Chang at Singapore’s Tourism Board said the 83-year-old guest aboard the Quantum of the Seas tested positive for COVID-19 after reporting to the ship’s medical center with diarrhea. All those in close contact with the man have been isolated and tested negative for the virus.

Chang said Wednesday that guests can only leave after contact tracing is completed and everyone on board is tested.

Singapore recently began a “safe cruising” pilot program allowing cruise ships to make round trips to Singapore with no port of call in between and heightened safety measures including pre-boarding testing for passengers.