Key Points

Monitoring of reports of nosocomial COVID-19 cases, e-SIN, France, from March 1, 2020, to June 17, 2022

• 76.5% of reports received since the start of the epidemic corresponded to clusters of cases (CG).

• 10: the median number of cases per outbreak.

• 34% of healthcare workers were involved in HCUs throughout the epidemic, a figure that has been gradually declining since Wave 5 (November 2021).

• The source of nosocomial CCs is predominantly a patient (57%).

• The two most frequently cited hypotheses to explain transmission are the failure to identify a case upon admission (45%) and breaches in the application of infection control measures (41%), particularly during patient care and when receiving families and visitors.