The U.S. Centers for Disease Control and Prevention says 281 out of 3,050 passengers aboard Royal Caribbean's Explorer of the Seas have reported symptoms including vomiting and diarrhea. A total of 22 crew members have also gotten sick.
In a Sunday statement, Royal Caribbean International spokeswoman Janet Diaz said the 15-deck cruise ship has undergone extensive cleaning. CDC officials are expected to soon board the vessel.
She says the people who got sick have "responded well to over-the-counter medication."
Norovirus symptoms include vomiting and diarrhea, which is what the cruise ship passengers have reported. The virus is known for afflicting schools and cruise ships.