Group 1 - The CDC confirmed a recent outbreak of norovirus on Royal Caribbean's "Serenade of the Seas," with 94 out of 1,874 passengers and 4 out of 883 crew members showing symptoms as of October 1 [1] - The cruise ship departed from San Diego on September 19 and reported the outbreak on September 28 after the number of cases exceeded 2% of the total onboard population [1] - Royal Caribbean emphasized enhanced cleaning and disinfection procedures, stating that the health and safety of passengers and crew are their top priority [1] Group 2 - The outbreak on "Serenade of the Seas" is one of several gastrointestinal disease incidents reported this year, with over 140 cases on "Navigator of the Seas" in July and over 90 cases on "Radiance of the Seas" in February [2] - The CDC has recorded 19 similar incidents in 2024, with 14 attributed to norovirus [3]