By Annika Inampudi and Ignacio Gonzalez May 17, 2026 (Bloomberg) – Stomach illnesses on cruise ships have recently reached the highest levels in nearly 20 years, showing how easily viruses can spread on these c...
By Annika Inampudi and Ignacio Gonzalez
May 17, 2026 (Bloomberg) – Stomach illnesses on cruise ships have recently reached the highest levels in nearly 20 years, showing how easily viruses can spread on these contained trips as more people are taking to the seas.
While cruise ships are under scrutiny due to a rare hantavirus outbreak that has killed three people on an ocean liner since April, gastrointestinal issues are much more common. These illnesses have been on the rise for the past four years, reaching the highest point since 2007, according to data from the Centers for Disease Control and Prevention (CDC) Vessel Sanitation Program. This program monitors ships with at least 13 passengers on international routes that stop at one or more U.S. ports.
The Vessel Sanitation Program records the number of stomach outbreaks that cruise ships report annually. An outbreak is defined as a situation where over 3% of passengers have some form of stomach illness.
A new variant of the norovirus in 2006 caused a significant rise in outbreaks on cruise ships. While the numbers dropped afterward, the outbreaks have climbed since the pandemic, reaching 23 last year, the highest since 2007, according to CDC data.
CDC officials noted that a new strain was linked to outbreaks on land last year. From January to mid-May 2025, there were 17 stomach flu outbreaks reported on cruise ships, but this year that number has dropped to four during the same period.
Hantavirus Shock
Passengers and crew from the MV Hondius are returning home from around the world after a deadly outbreak of the Andes strain of hantavirus occurred on the ship last month. Although the ship did not dock at a U.S. port, it has drawn attention from Americans and travelers worldwide, recalling memories of a cruise ship quarantined off the coast of Japan during the Covid-19 pandemic in 2020.
Most cruise lines suspended operations during the peak of the Covid-19 pandemic, but the industry is now thriving again. According to the Cruise Lines International Association, global cruise passenger numbers reached a record 37 million in 2025, and demand is expected to continue into 2026.
Health concerns have not diminished demand; according to analyst Jaime Katz from Morningstar Inc., advance bookings at Carnival Corp. and Royal Caribbean Cruises Ltd. are stable.
“There’s some hesitation in making bookings until consumers understand the full impact of the outbreak,” she said.
Carnival and Royal Caribbean did not respond to requests for comments. Norwegian Cruise Line Holdings Ltd. directed inquiries to the Cruise Lines International Association.
Cruise ships are required to report outbreaks, which makes them more visible, and illness rates on these ships remain lower compared to land-based hospitality settings, according to the association's statement.
“If you're going on a cruise, understand that the risk is higher,” said Abraar Karan, a Stanford University infectious diseases instructor. He explained that close human interactions and shared food and water systems can speed up the transmission of diseases, and limited medical resources make it harder to control outbreaks.
Additionally, since the typical cruise passenger is older, they may be more susceptible to infections, Karan noted, recommending that travelers wear masks when respiratory illnesses are present onboard and practice good hand hygiene.
“Cruises are a lot of fun,” he concluded. “But that's just part of the trade-off.”