CDC reports largest cruise ship illness outbreak of 2025 on Queen Mary 2

A gastrointestinal illness outbreak aboard the Queen Mary 2 has affected more than 200 passengers and crew, making it the largest cruise-related outbreak reported so far this year, according to data from the U.S. Centers for Disease Control and Prevention (CDC).

The Cunard Line cruise ship, currently on a month-long voyage from March 8 to April 6, reported the outbreak to the CDC’s Vessel Sanitation Program (VSP) on March 18.

At least 224 passengers out of 2,538 (8.8%) and 17 crew members out of 1,232 (1.4%) have reported symptoms consistent with norovirus. The predominant symptoms reported were diarrhea and vomiting.

In response, Cunard Line and the ship’s crew implemented enhanced cleaning and disinfection measures, isolated affected individuals, and collected stool specimens for testing. The CDC said VSP is remotely monitoring the outbreak and reviewing the ship’s response procedures.

Norovirus is a highly contagious virus known to cause acute gastroenteritis and is a frequent source of outbreaks aboard cruise ships.

Gastrointestinal illness outbreaks are not uncommon on cruise ships due to the close quarters and shared dining spaces. The CDC requires ships to report cases of acute gastroenteritis that meet its definition: three or more loose stools in a 24-hour period or vomiting accompanied by another symptom such as abdominal cramps or fever.

So far this year, the CDC has reported gastrointestinal illness outbreaks on 12 cruise ships, mostly linked to norovirus. The Queen Mary 2 outbreak is currently the most widespread of 2025 in terms of total affected passengers and crew.