Introduction: The SARS-Cov-2 outbreak in France and the concomitant massive increase in the number of cases requiring hospital management create a major risk of COVID-19 infection for hospital staff. In addition to nosocomial transmission, the health care workers (HCWs), defined as persons serving in health care settings who have the potential for direct or indirect exposure to patients or infectious materials, are also exposed to community transmission. Whether HCWs acquire infection at work or in the community is important to adapt protection measures. A few studies investigated COVID-19 infection among medical and nursing personnel. However, none have analyzed all categories of hospital staff. As of April 9, 2020, a total of 9,282 US HCWs with confirmed COVID-19 had been reported to CDC (US), however description of occupational activities was not available. Therefore, limited information is available about COVID-19 infection among HCWs. Thus, the objectives of the sdudy are to estimate the incidence of symptomatic SARS-CoV-2 infection in HCWs in five university hospitals (including geriatric hospitals) of the great Paris area and to estimate both nosocomial and community risk factors. Method: A prospective and retrospective cohort study that includes all hospital staff (including medical and nursing personnel, health care managers, laboratory, radiology, reception staffs, stretcher-bearers, etc.) working in different departments of five university hospitals (acute medical centers and geriatric hospitals) in the great Paris area (9 000 HCWs). Incidence of symptomatic SARS-CoV-2 infection will be estimated with its 95%CI. Individual and contextual risk factors will be analyzed using multilevel multivariate logistic regression modelling to account for clustering and confounding. Conclusion This study should make it possible to better characterize SARS-Cov-2 contamination of HCWs and to estimate the share of nosocomial transmission.