How Not To Get Sick on a Cruise

Here’s the Best Way to Protect Yourself From a Norovirus Outbreak

This 3D graphical representation of norovirus particles is based on electron microscopic imagery of actual virus particles. Credit: CDC/Jessica A. Allen

(Rachael Rettner, Live Science) It’s a vacation nightmare: You board a cruise ship for a weeklong getaway, only to have an outbreak of norovirus, or a “stomach bug,” take the ship by storm.

But aside from barricading yourself in your cabin, what’s the best way to protect yourself if you find yourself in the midst of a norovirus outbreak?

In a new study, researchers employed some fairly complicated math to find a pretty simple answer to that question: Wash your hands.

“When your mother told you to always wash your hands before coming to the dinner table… she was right,” study lead author Sherry Towers, a professor at Arizona State University said.

Norovirus is a highly contagious stomach virus that causes diarrhea and vomiting. It can spread from person to person — for example, by shaking hands, or caring for someone who is sick — or by eating contaminated food or touching contaminated surfaces.

Norovirus is well-known for causing outbreaks in settings where people share close quarters, such as at conventions, at the Olympics, and yes, on cruise ships. In 2017, the Centers for Disease Control and Prevention documented nine norovirus outbreaks on cruise ships that sickened hundreds of people.

Viral math

To better understand these outbreaks and how to prevent them, the researchers created a mathematical model of a norovirus outbreak using data from a cruise ship outbreak in 2002 that sickened more than 400 passengers and crew on two consecutive cruises.

First, the researchers calculated the “reproduction number,” or the average number of people infected by a single sick person in a susceptible population.

They found that, for this outbreak, the reproduction number was 7.2. That’s fairly high; for comparison, the reproduction number for seasonal flu is about 1.3, according to a 2014 review study. Read the full story on LiveScience.