A Norovirus and Rotavirus Co-Infection Outbreak Investigation in a Primary School — Pudong New Area, Shanghai Municipality, China, March 2025

What is already known about this topic?: Co-infection outbreaks involving norovirus and rotavirus in school settings highlight the essential role of stringent hygiene protocols and rapid, coordinated public health responses in mitigating acute gastroenteritis transmission. What is added by this report?: This outbreak revealed a norovirus-rotavirus co-infection outbreak in a primary school. The outbreak affected 14 cases within a single class (38.9% attack rate), all presenting with mild symptoms. Laboratory testing revealed co-infection in 1 anal swab sample and 4 environmental samples (both norovirus GI and rotavirus A positive). Importantly, family-based active case surveillance identified 1 asymptomatic norovirus GI carrier. What are the implications for public health practice?: It is worth noting that individuals with atypical symptoms and socially active individuals warrant heightened attention during outbreak investigations. Pathogen identification is critical, as different pathogens exhibit distinct transmission characteristics that inform control strategies. This outbreak provides valuable real-world evidence to guide future outbreak response protocols.