1 Department of Health Sciences, School of Medical and Pharmaceutical Sciences, Postgraduate School in Occupational Medicine, University of Genoa and Medical Surveillance Unit for Health Care Workers, Occupational Medicine Unit, IRCCS San Martino Hospital, Largo R. Benzi 10, 16132 Genoa, Italy.
2 NIHR Wellcome Trust Clinical Research Facility, University of Southampton, C Level, West Wing, Mailpoint 218, UK ; University Hospital Southampton NHS Foundation Trust, Tremona Road, Southampton SO16 6YD, UK.
3 Pneumology Department, Clinic Institute of Thorax, Hospital Clinic of Barcelona, Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), University of Barcelona, Ciber de Enfermedades Respiratorias (CIBERES), Villarroel 170, 08036 Barcelona, Spain.