Viral co-infections in pediatric acute gastroenteritis: epidemiology of rotavirus, norovirus, adenovirus, and astrovirus in Tehran, Iran (2021–2022)

Acute gastroenteritis (AGE) is a prevalent gastrointestinal illness and a leading cause of morbidity and mortality among children younger than 5 years of age. Viral pathogens, group A rotavirus (RVA), norovirus (NoV), adenovirus (AdV), and astrovirus (AstV), account for over 70% of AGE cases in this age group. Co-infections with multiple enteric viruses are frequently observed in developing regions with Limited healthcare infrastructure and may contribute to increased pathogenicity, reduced vaccine efficacy, and viral evolution. This study aimed to investigate the prevalence and clinical features of RVA, NoV, AdV, and AstV infections, including patterns of viral co-infection, among children under 5 years of age with AGE in Tehran, Iran. From January 2021 to January 2022, 200 stool specimens were collected from children under 5 hospitalized with AGE at children’s hospitals in Tehran. They were tested for RV, AdV, and AstV using RT-PCR, and for NoV, via real-time PCR. The overall prevalence rate for RV, NoV, AdV, and AstV was 24%, 22%, 14%, and 0.5%, respectively. In total, 72% of the samples tested positive for at least one enteric virus, and co-infections were detected in 11.5% of them. The most common co-infection among this population was RV-AdV (25.6%), and RV was the most frequently co-detected virus with NoV, AdV, and AstV. Our findings highlight that RV was the most frequently detected virus, followed by NoV, AdV, and AstV. The notable rate of co-infections underscores the need for multiplex diagnostics and may inform vaccination strategies to better prevent severe pediatric gastroenteritis.