The ship is now docked in Marseille, France, and French health authorities have boarded to conduct health checks. Americans on board have been told that a chartered plane will take them to Atlanta. Various government agencies are involved in figuring out what to do with them next, and some U.S. states may allow them to isolate at home, as some people who sailed on the Grand Princess did, the Centers for Disease Control and Prevention said.

When cruise lines decided to suspend U.S. sailings last week 40 ships carrying tens of thousands of passengers were in the middle of their voyages. On at least three of them, passengers got Covid-19 while cruise ship companies, port officials, governments and international health organizations scrambled to determine whose rules applied. Thousands of people were at sea, sometimes confined to tiny cabins, but also enjoying the bar, serving themselves from the buffet and enjoying festivities while more people contracted the disease and the ship captains tried to figure out what to do.

The Braemar, a ship operated by Fred. Olsen Cruise Lines, was denied entry by four countries when a guest, four crew members and two passengers who had been on the ship tested positive. Cuba opened its port to them, and about 700 mostly British passengers took chartered flights home to England on Wednesday. Also Wednesday, nearly 100 passengers who had been in quarantine — with six infected passengers aboard the Silver Explorer cruise off the coast of Chile — were flown out of that country on charter flights, according to Chilean officials.

Meanwhile, passengers aboard the Silver Shadow were close to completing a week in quarantine in the port of Recife in northern Brazil over coronavirus fears that are so far unfounded. Both the Silver Explorer and Silver Shadow are operated by Silversea Cruises, which is owned by Royal Caribbean.

The Costa Luminosa, a 965-foot-long ship built in 2009, is owned by the Crociere Group, Italy’s biggest tour operator. Headquartered in Genoa, the company has 27 ships in service that offer trips from the Mediterranean to South America.