Planning A Cruise? Here’s How To Dodge The Most Common Germs At Sea

FRIDAY, Nov. 13, 2026 (HealthDay News) — Norovirus is still the top cause of cruise ship outbreaks, but flu, COVID-19 and other germs are claiming a bigger share, a new review finds.

Researchers at Peking University in China pooled data from 107 studies covering 619 outbreaks on 236 ships between 1969 and 2026. The findings were published Nov. 9 in eClinicalMedicine.

Cruise ships are crowded, partly enclosed spaces where people from around the world “live and dine in close proximity,” the authors wrote. Shared facilities and a steady turnover of passengers make it easy for germs to spread.

Norovirus was responsible for 57.8% of the outbreaks, reports CIDRAP News. This highly contagious stomach bug has been the most common culprit since the mid-1990s.

Overall, nearly 7 in 10 outbreaks involved stomach or intestinal illness. Other germs included a type of E. coli  bacteria (5% of outbreaks); the virus that causes COVID (3.4%); and the flu (3.1%). In about 17% of outbreaks, the cause was never confirmed.

Who got sick depended on the germ. During a typical norovirus outbreak, 6.5% of passengers fell ill, compared with 1.5% of crew members.

COVID-19 flipped that pattern, infecting 26.4% of crew versus 5.1% of passengers. The researchers noted those estimates were less precise. Flu affected both groups at similar rates.

Deaths were uncommon, with one exception. Legionella bacteria killed about 11% of those infected.

The researchers think expedition cruises, with more trips ashore, may help explain why the mix of germs is changing. 

Earlier this year, an Andes hantavirus outbreak on an expedition ship sickened 13 people and killed three. The passengers were likely exposed during bird-watching outings in South America through contact with infected rodents.

Researchers called for standard outbreak reporting and better tracking, including testing a ship’s wastewater for early signs of illness.

The U.S. Centers for Disease Control and Prevention (CDC) notes that outbreaks may seem more common at sea partly because they’re spotted faster. Crew members must report symptoms right away, and ships are required to report certain illnesses.

To stay healthy on board, the CDC recommends that cruisers:

• Tell the ship’s medical center if they’re sick.

• Wash their hands often, rather than relying on hand sanitizer.

• Drink plenty of water and get enough rest.

• Leave the area if someone nearby vomits or has diarrhea.

If the medical center asks a sick passenger to stay in their cabin, they should follow that advice, the agency says. Isolating helps protect young children, older adults and people with weakened immune systems.

Parents shouldn’t assume a vomiting child is just seasick, the CDC adds. And anyone who gets sick after a cruise should see a doctor and mention the recent trip.

More information

Visit the U.S. Centers for Disease Control and Prevention for more information about staying healthy on a cruise.

SOURCES: CIDRAP News, Nov. 9, 2026; U.S. Centers for Disease Control and Prevention, Sept. 2, 2026