1 million people worldwide since early 2020. 1 Age is one of the main risk factors for death 2 from coronavirus disease-2019 (COVID-19). 2 In France, a third of COVID-19 deaths occurred 3 in long-term accommodation establishments for dependent elderly people (nursing homes). 3 4 Uncertainties persist on the relative importance of modes of transmission of SARS-CoV-2, 5 but it is widely accepted that it is transmitted by respiratory droplets and by hands 6 (especially through contact with contaminated surfaces). 4 The relative contribution of 7 airborne versus surface transmission of COVID-19 remains unclear. Several antimicrobial 8 surfaces have been studied and used around the world to prevent human-to-human 9 transmission of SARS-CoV-2. Copper is a metallic element well known for its antimicrobial 10 properties and in vitro studies have shown that coronaviruses do not survive for a long time 11 on it. 5, 6 12 13 A nursing home in France is divided into 2 distinct identical and symmetrical wings. In 2014, 14 one of them was equipped with elements (door handles, handrails and grab bars) covered 15 with a copper alloy, known to be antimicrobial. This structure, with its two identical wings, 16 but different by the copper equipment, enables to evaluate the epidemic spread in each 17 wing, and to assess the preventive effectiveness of copper. 18 We therefore carried out a quasi-experimental study within this nursing home, to study the In terms of prevention, even if transmission through hands must be combated by regular 43 hand washing, its relative weight is likely to be less than that of transmission by respiratory 44 droplets. 