More than 120 passengers and crew members aboard a Princess Cruises ship contracted norovirus during a 20-day voyage, federal health officials confirmed Thursday after the vessel docked in San Francisco.

102 Passengers and 23 Crew Members Infected

The Ruby Princess was on a round trip journey from San Francisco to Canada and Alaska when the outbreak took hold, the US Centers for Disease Control and Prevention said. Of the ship’s 3,032 passengers and 1,144 crew members, 102 passengers and 23 crew were stricken by the highly contagious stomach virus. The ship set sail on June 12, and the Ruby Princess norovirus outbreak was reported to the CDC on Saturday. Officials noted that not all infected individuals were sick simultaneously or at the time the ship departed or arrived at port.

What Is Norovirus and How Does It Spread

Norovirus is one of the most contagious viruses known, spreading readily through contaminated food, water, and surfaces — conditions that make crowded environments like cruise ships particularly vulnerable. Symptoms include sudden-onset vomiting, diarrhea, and stomach cramps that typically last up to three days. While the illness is brief and self-limiting for most healthy adults, it can be dangerous for people with underlying health conditions, young children, and adults aged 65 and older.

Most outbreaks occur when infected individuals spread the virus directly to others through shared food, utensils, or close contact. Contaminated surfaces are also a common transmission route.

Ship to Be Thoroughly Cleaned Before Next Voyage

Princess Cruises said in a statement that the ship’s crew responded promptly and implemented enhanced sanitation protocols throughout the vessel once the outbreak was identified. The company said the Ruby Princess would be thoroughly cleaned and disinfected before departing on its next voyage later Thursday.

Seven Cruise Ship Outbreaks So Far in 2026

The Ruby Princess incident is the seventh illness outbreak reported on cruise ships within the CDC’s jurisdiction so far this year, with norovirus responsible for the majority of cases. The CDC recommends frequent and thorough handwashing — using soap and water for at least 20 seconds — as the most effective measure against norovirus, particularly after using the bathroom and before eating or drinking. The agency cautions that hand sanitizer alone is not reliably effective against the virus.

Author: Staff Writer | Edited for WTFwire.com | SOURCE: NBC News