Efficacy of Ultraviolet Germicidal Irradiation Devices to Reduce Respiratory Infections in Nursing Homes: Cluster Randomized Crossover Trial

Center Inclusion criteria: Elderly Nursing homes (ENH): * Having a system for monitoring cases of upper and lower respiratory infections among their residents. * Agreeing to take part in the study * Undertaking to comply with the protocol * Accepting the installation of UVGI devices * Undertaking to provide all residents or their legal guardians/curators with an individual information leaflet. Center Exclusion criteria: ENH: * Not wishing to be equipped with UVGI devices in all rooms considered necessary to be equipped by the investigators * Having planned a major change to the structure (extension, renovation, closure, requalification, etc.) during the course of the study, which could affect the study population and/or UVGI air treatment devices. Individual Inclusion criteria: All residents present in one of the participating ENH at the start of each of the two study periods, or arriving in one of the participating ENH during one of the two periods, will be eligible Individual Exclusion criteria : Residents of the ENH included in the study who have expressed (personally or through a relative or legal representative) the wish that their personal data not be used for the study will not be included in the study.