More than 100 passengers and 23 crew members on the Ruby Princess cruise ship were infected with norovirus during a 20-day voyage from San Francisco to Canada and Alaska, according to the U.S. Centers for Disease Control and Prevention (CDC). The outbreak, reported on June 28, affected 102 passengers (3.4%) and 23 crew members (2%) of the ship's total 3,032 passengers and 1,144 crew members. Symptoms included vomiting, diarrhea, and stomach pain, typical of norovirus, which is highly contagious and spreads through contaminated surfaces, food, or direct contact.
Princess Cruises implemented enhanced sanitation protocols and isolated infected individuals to contain the outbreak. The ship docked in San Francisco on July 2 and underwent deep cleaning before its next voyage. The CDC’s Vessel Sanitation Program (VSP) monitored the response and reviewed sanitation procedures.
Norovirus outbreaks are common on cruise ships due to close quarters and shared spaces. The CDC has reported seven illness outbreaks on cruise ships in 2026, including three norovirus cases. The virus can persist for up to two weeks after symptoms subside, increasing transmission risks.
Passengers and crew who fell ill were isolated, and the cruise line collected stool samples for testing. Princess Cruises stated that cases have since decreased and remain low after implementing stricter hygiene measures.
The Ruby Princess departed June 12 and returned July 2, with the outbreak first detected on June 28. The CDC emphasized that norovirus is not life-threatening for most people but can be dangerous for young children, the elderly, and those with weakened immune systems.