Preventing an influenza outbreak in an acute care requires a multimodal intervention, taking into account the actors involved (influenza virus, staff, patients, visitors), and the stage of the epidemic. Different means are used for this purpose : immunization, use of alcohol-based hand rub, identification of influenza cases, wearing of medical masks, social distance, and antiviral treatment. In addition, an epidemiological surveillance of influenza cases, in the general population and within the health facilities, must be associated.