Global Health Rotavirus was the leading cause of diarrhea requiring hospitalization among young children in 28 low- and middle-income countries despite the introduction of rotavirus vaccine, according to a study published in BMJ Global Health. Overall, the leading causes of diarrhea requiring hospitalization were rotavirus - which accounted for a third of cases - followed by I Shigella i , norovirus, and adenovirus types 40 and 41.