Norovirus Upsets Spring Break for Cruisers

The U.S. Centers for Disease Control and Prevention (CDC) recently confirmed more than 300 people became ill on a Galveston, Texas, based cruise ship last week.

On March 7, 2023, the CDC's Investigation Update regarding vomiting and diarrhea on the Princess Cruises' Ruby Princess voyage #RU305P determined:

• passengers who reported being ill during the voyage: 284 of 2881 (9.9%),
• crew reporting being ill: 34 of 1159 (2.9%).

According to Houston Public Media, Briana Latter, a spokesperson for Princess Cruises, wrote in an emailed statement that there were cases of "mild gastrointestinal illness" on board the ship.

She did not answer a question to determine whether passengers or crew members were hospitalized after disembarking – a detail not addressed in an online report released by the CDC.

"The cause likely is the common but contagious virus called norovirus," Latter added.

The Ruby Princess was disinfected before another set of passengers and crew members embarked on another cruise shortly after the infected group arrived on Galveston Island on March 5, 2023.

While the Ruby Princess remained at sea, the CDC said Princess Cruises increased cleaning and disinfection procedures, notified all guests about the outbreak, and collected stool samples from those infected so the samples could be sent to a CDC lab for testing.

Latter said Princess Cruises' sanitization program, developed in coordination with the CDC, includes disinfecting high-touch surfaces like railings, door handles, and elevator buttons; encouraging passengers to use their in-cabin restrooms along with washing their hands and using hand sanitizer; and isolating ill passengers in their cabins until they no longer are contagious.

"At the first sign of an increase in the numbers of passengers reporting to the medical center with gastrointestinal illness, we immediately initiated additional enhanced sanitization procedures to interrupt the person-to-person spread of this virus," Latter commented.

The CDC posts current norovirus outbreaks and alerts at this link.

Noroviruses are very contagious RNA viruses. They are the most common viral pathogens causing epidemic and endemic acute gastroenteritis.

Previously, the U.S. Food and Drug Administration (FDA) reported an unrelated food-based norovirus outbreak in late February 2023.

The FDA announced it was working with local officials and Canadian public health authorities on a norovirus outbreak linked to raw oysters from British Columbia, Canada. 

While norovirus vaccines are in demand, the FDA and the European Medicines Agency have not approved a vaccine candidate as of March 9, 2023.

A leading candidate in development is HilleVax, Inc. HIL-214 virus-like particle-based bivalent vaccine, being tested to prevent moderate-to-severe acute gastroenteritis caused by norovirus.

HIL-214 has been studied in nine clinical trials and generated safety data from more than 4,500 subjects.