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.