90-Second Read: Stomach Bugs, Not Hantavirus, Are the Bigger Threat on Cruises

While cruises are in a global spotlight after a rare Hantavirus outbreak killed three people on an ocean liner since April, mild gastrointestinal illnesses are far more common on ships. The Vessel Sanitation Program tracks the number of gastrointestinal outbreaks that cruise ships report every year, defined as situations when more than 3% of people on board have some kind of stomach illness. Passengers and crew from the MV Hondius are returning home throughout the world after the deadly outbreak of the Andes strain of Hantavirus spread on the ship last month. The data tracks ships with 13 or more passengers with foreign itineraries that dock at one or more US ports.

They subsequently declined but the number of such outbreaks has risen since the pandemic period and last year reached 23, the highest number since 2007, according to CDC data. Most cruises halted voyages during the height of the COVID-19 pandemic, but since then the industry has been booming. Cruise ships operate under strict mandatory reporting that makes outbreaks more visible and illness rates on-board remain below hospitality settings on land, the association said in a statement. The ship did not dock at a US port but has caught the attention of Americans as well as travelers globally.

They have risen for the last four years to the highest since 2007, according to data from the Centers for Disease Control and Prevention's Vessel Sanitation Program. Health concerns in the past haven't dented demand, and this year advance bookings at Carnival Corp. Dense socializing spaces, as well as shared food and water systems, can accelerate the spread of diseases, while limited medical equipment and staffing make curbing infections harder, he said. The average cruise-goer also is older and may be more likely to pick up infections, said Karan, who recommends wearing a mask on ships where respiratory illness is found and washing your hands.

Global cruise passenger volume reached a record 37 million in 2025, with demand expected to persist into 2026, according to the Cruise Lines International Association. There's an initial hesitation on booking until consumers are able to distill the magnitude of the impact of that outbreak.