Real-Time Investigation of a Large Nosocomial Influenza A Outbreak Informed by Genomic Epidemiology.

Background: Nosocomial respiratory virus outbreaks represent serious public health challenges. Rapid and precise identification of cases and tracing of transmission chains is critical to end outbreaks and to inform prevention measures.

Methods: We combined conventional surveillance with influenza A virus (IAV) genome sequencing to identify and contain a large IAV outbreak in a metropolitan healthcare system.