The cruise industry is experiencing not only incredible growth, with projections of 37.1 million passengers expected to set sail by 2025, but also facing troubling statistics as the year wraps up. According to new data released by the U.S. Centers for Disease Control and Prevention (CDC), 2024 marked the worst year for gastrointestinal outbreaks on cruise ships since the agency began tracking such incidents over ten years ago, largely due to the highly contagious norovirus.
Reports indicate there were 16 outbreaks related to stomach illnesses aboard cruise ships last year, with the CDC stating this affected more than 1,894 passengers and 245 crew members. December alone saw five separate outbreaks, with 781 passengers and 109 crew members taken ill, mainly from diarrhea and vomiting. Norovirus was cited as the leading cause of 14 of these outbreaks, aligning with the virus’ known propensity to thrive where people congregate closely, as is the case on many vessels.
“This is a virus can infect you with very few viral particles,” said Dr. William Schaffner, infectious disease expert and professor at Vanderbilt University Medical Centre. "It can persist for days or even a week on environmental surfaces, which means if you put your fingers on contaminated surfaces, you can pick up viral particles and initiate an infection." Its spread isn’t limited to ships, as norovirus is notorious for outbreaks among people crowded together, such as at camps, dormitories, and even hotels.
Historically, norovirus cases tend to peak between November and April, but experts have reported this season seems particularly severe. The number of outbreaks aboard cruise ships reflects wider patterns seen across the U.S., as norovirus illnesses continue to increase nationwide. Prior to 2024, the total number of outbreaks aboard cruise ships was remarkably low, with the CDC previously attributing the significant drop during the COVID-19 pandemic. Restrictions on travel meant there were fewer opportunities for outbreaks as the industry temporarily shut down.
The CDC declared it was difficult to say whether the increases seen over the past two years would mark the beginning of new trends or simply represent fluctuations as normalcy returns. “While 2023 and 2024 both had higher numbers of cruise ship outbreaks than years prior to the pandemic, we do not yet know if this represent(s) a new trend,” the spokesperson remarked.
Before 2020, the rates of gastrointestinal illnesses on cruise ships had decreased significantly between 2006 and 2019, averaging about 12 outbreaks annually. The uptick during 2023 and 2024 compared to pre-pandemic years raised alarms about the conditions aboard some cruise ships.
To combat the spread of the virus, cruise lines have implemented various measures. Health authorities encourage passengers who feel ill to report their symptoms immediately to limit the potential for contagion. “For anyone showing symptoms of norovirus, prompt reporting is key,” urged the CDC. Passengers are also advised to maintain stringent hygiene practices, particularly after using facilities and before meals, with hand-washing recommended over hand sanitizers for maximum effectiveness against norovirus.
The Cruise Lines International Association (CLIA) has emphasized to travelers, “incidents of illness onboard cruise ships are extremely rare,” pointing out the extensive measures taken to control outbreaks, such as quarantine protocols for symptomatic crew and passengers and enhanced cleaning practices. Nevertheless, experts like Dr. Schaffner caution against complacency, noting the innate challenges presented by the sheer contagiousness of norovirus. "It is likely to go beyond all those barriers and interventions put in place by cruise companies," he added, emphasizing the unpredictable nature of this winter season's virus trends.
For those thinking about embarking on a cruise, experts recommend taking precautions seriously. Dr. Schaffner advised, "number one, if you're feeling at all ill, stay home, rebook for a later cruise. Number two, pay attention to all hygienic instructions you are provided on the cruise ship. And particularly pay attention to hand hygiene; soap and water is actually more effective than using sanitary hand wipes or lotions, as norovirus is not as affected by the alcohol present in those products."
With the holiday season upon us and cruise bookings on the rise, the conversation around public health and safety onboard continues to gain traction as health officials double down on preventive strategies to manage and contain norovirus outbreaks. For the cruise industry, addressing these public health challenges will be key as it charts its course for the future.