More than 100 passengers and 23 crew members have fallen ill during a suspected norovirus outbreak aboard the Ruby Princess cruise ship, according to the US Centers for Disease Control and Prevention (CDC).
The vessel departed San Francisco on 12 June for a cruise to Alaska and Canada before returning to California on 2 July.
The CDC said the outbreak was reported more than two weeks into the voyage after the number of illnesses exceeded the agency’s outbreak threshold.
The Ruby Princess was carrying 3,032 passengers and 1,144 crew members and was docked in San Francisco on Thursday for cleaning and disinfection.
According to the CDC, norovirus is a highly contagious virus that commonly causes vomiting and diarrhoea. It spreads through contaminated food, surfaces or close contact with infected people.
The affected passengers and crew have been isolated while enhanced cleaning measures are carried out on board.
The CDC said this is the third reported outbreak affecting a Princess Cruises ship this year.
Overall, seven norovirus outbreaks have been reported on cruise ships during 2026, highlighting the challenges of controlling highly contagious illnesses in shared environments.
