Epidemiology and Factors Related to Clinical Severity of Acute Gastroenteritis in Hospitalized Children after the Introduction of Rotavirus Vaccination.

We aimed to investigate epidemiology and host- and pathogen-related factors associated with clinical severity of acute gastroenteritis (AGE) in children after rotavirus vaccination introduction. Factors assessed included age, co-infection with more than 2 viruses, and virus-toxigenic Clostridium difficile co-detection. Fecal samples and clinical information, including modified Vesikari scores, were collected from hospitalized children with AGE. The presence of enteric viruses and bacteria, including toxigenic C. difficile, was detected by polymerase chain reaction (PCR). Among the 415 children included, virus was detected in stool of 282 (68.0%) children. Co-infection with more than 2 viruses and toxigenic C. difficile were found in 24 (8.5%) and 26 (9.2%) children with viral AGE, respectively. Norovirus (n = 130) infection, including norovirus-associated co-infection, was the most frequent infection, especially in children aged < 24 months (P < 0.001). In the severity-related analysis, age < 24 months was associated with greater diarrheal severity (P < 0.001) and modified Vesikari score (P = 0.001), after adjustment for other severity-related factors including rotavirus status. Although the age at infection with rotavirus was higher than that for other viruses (P = 0.001), rotavirus detection was the most significant risk factor for all severity parameters, including modified Vesikari score (P < 0.001). Viral co-infection and toxigenic C. difficile co-detection were not associated with any severity-related parameter. This information will be helpful in the management of childhood AGE in this era of rotavirus vaccination and availability of molecular diagnostic tests, which often lead to the simultaneous detection of multiple pathogens.