inclusion criteria: * medical doctor, nurse ,respiratory therapist or nurse assistant who work in the emergency room, general covid ward or intensive care unit * age : between 18-70 years * rt-pcr and serology tests for sars-cov-2 negative at baseline evaluation * direct care of patients in the emergency room, general covid wards or intensive care unit * informed consent signed

inclusion criteria: * medical doctor, nurse ,respiratory therapist or nurse assistant who work in the emergency room, general covid ward or intensive care unit * age : between 18-70 years * rt-pcr and serology tests for sars-cov-2 negative at baseline evaluation * direct care of patients in the emergency room, general covid wards or intensive care unit * informed consent signed

inclusion criteria: - medical doctor, nurse ,respiratory therapist or nurse assistant who work in the emergency room, general covid ward or intensive care unit - age : between 18-70 years - rt-pcr and serology tests for sars-cov-2 negative at baseline evaluation - direct care of patients in the emergency room, general covid wards or intensive care unit - informed consent signed

inclusion criteria: - medical doctor, nurse ,respiratory therapist or nurse assistant who work in the emergency room, general covid ward or intensive care unit - age : between 18-70 years - rt-pcr and serology tests for sars-cov-2 negative at baseline evaluation - direct care of patients in the emergency room, general covid wards or intensive care unit - informed consent signed