Cruise Ships Face Worst Year for Stomach Bugs in Over a Decade, CDC Data Reveals
The cruise industry continues to grow rapidly, with approximately 37.1 million passengers expected to set sail in 2025, according to Cruise Lines International Association (CLIA). However, alongside this growth, another troubling statistic has emerged. Data from the U.S. Centers for Disease Control and Prevention (CDC) reveals that 2024 has seen the worst year for gastrointestinal outbreaks on cruise ships in over a decade.
Norovirus Outbreaks at Sea
The majority of gastrointestinal outbreaks on cruise ships in 2024 have been linked to norovirus, a highly contagious stomach bug. In December alone, five ships, including those from Cunard Line, Holland America, and Princess Cruises, reported widespread illness, with hundreds of passengers affected. The CDC considers an outbreak when 3% or more of a ship’s passengers and crew exhibit gastrointestinal symptoms.
Norovirus has long been associated with cruise ships due to the confined nature of these vessels, which makes it easier for the virus to spread. Dr. William Schaffner, an infectious disease expert at Vanderbilt University, notes that norovirus is “known obviously as the cruise ship virus.” The virus can spread quickly in close quarters, and even a small amount of the virus can cause illness. It also lingers on surfaces, making it easy for passengers to contract the virus if they touch contaminated areas.
A More Severe Season
Norovirus tends to peak during the winter months, but this season has been particularly severe, both on land and at sea. Dr. Schaffner attributes the high number of outbreaks in December 2024 to this more intense seasonal occurrence.
Despite this, the cruise industry maintains that gastrointestinal incidents on board are extremely rare. The Cruise Lines International Association emphasized in a statement that these outbreaks are reported more quickly on cruise ships than on land, thanks to strict reporting protocols. On average, the CDC records 19-21 million cases of norovirus in the U.S. annually.
Other Causes of Outbreaks
While norovirus dominated the 2024 outbreaks, other causes of gastrointestinal illness have been reported as well. In September 2024, a salmonella outbreak was reported on Royal Caribbean’s Radiance of the Seas. Additionally, an E. coli outbreak occurred on Silversea Cruises’ Silver Nova earlier in the year, and the cause of another outbreak on Royal Caribbean’s Allure of the Seas remains unknown.
Rising Outbreak Numbers
In total, the CDC recorded 16 gastrointestinal outbreaks on cruise ships in 2024, the highest number in over a decade. By comparison, there were 14 outbreaks in 2023. However, a CDC spokesperson cautioned that while recent years have seen higher numbers of outbreaks than in the years before the pandemic, it is still unclear whether this represents a new trend. The period between 2020 and 2022 saw fewer outbreaks, largely due to the cruise industry’s shutdown during the COVID-19 pandemic.
Guidelines for Staying Healthy Onboard
The CDC advises passengers to report any symptoms of stomach illness immediately and follow medical staff recommendations to help prevent further spread. Hand hygiene is also crucial, and passengers are encouraged to wash their hands thoroughly after using the toilet and before eating or drinking. While cruise ships take extensive measures to control outbreaks—such as quarantining ill passengers and increasing cleaning protocols—the highly infectious nature of norovirus means that these measures are not always fully effective.
Dr. Schaffner adds that despite the best efforts of cruise lines, norovirus is so contagious that it is likely to spread beyond these preventive measures. He suggests that travelers who feel ill should stay home and rebook their cruise, and be particularly vigilant about hand hygiene, using soap and water instead of hand sanitizers, which are less effective against norovirus.
Looking Ahead
Experts remain uncertain about whether the surge in norovirus cases will continue into 2025. Dr. Schaffner notes that predicting the future of norovirus outbreaks is difficult, and it’s best to “wait and see.” In the meantime, passengers should prioritize hygiene and health while aboard, ensuring they follow all safety guidelines provided by the cruise line.
