The evolving epidemiology of acute gastroenteritis in hospitalized children in Italy.

Few data are available on the prevalence and features of acute gastroenteritis (AGE) in hospitalized children in Italy, where specific rotavirus vaccines were introduced into the national vaccination plan in 2017. To evaluate vaccination effects on AGE epidemiology, we analysed data from children aged ≤ 18 years admitted for AGE at the University Hospital of Pisa in 2019, comparing them with those recorded in 2012. Demographical, clinical, diagnostic, and treatment data were collected reviewing medical records and were therefore compared. In 2019 and 2012, 86 (median age 2.5 years [IQR 1.4-5.9]) and 85 children (median age 2.3 years [IQR 1.3-5.1]) were respectively admitted with AGE. The most common symptoms were diarrhoea and vomiting; decreased skin turgor was more frequent in 2019 (54% and 34% respectively, p = 0.01). Viral infections were more common than bacterial ones; in 2019, a decrease in rotavirus infections (67% and 22%, p = 0.003) and an increase in adenovirus infections (50% and 10%, p = 0.002) and in the number of patients with negative stool testing (58% and 39%, p = 0.04) were found.Conclusions: Viral infections are the leading cause of AGE in hospitalized children in Italy. The introduction of rotavirus vaccines did not reduce the number of hospitalizations per year. Adenovirus and other non-routinely screened viruses may be undergoing a selection process making them common causative agents for AGE. What is Known: • Rotavirus is the leading cause of acute severe gastroenteritis in children worldwide, especially < 5 years of age. • The introduction of specific vaccines may be changing its epidemiology. • Few data are available on acute gastroenteritis in hospitalized children in Italy. What is New: • Viral infections are the leading cause of acute gastroenteritis in hospitalized children in Italy. • Specific vaccines are reducing rotavirus infections, but adenovirus and other non-routinely screened viruses may be undergoing a selection process making them common causative agents for gastroenteritis.