1. Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
2. Department of Internal Medicine, Respiratory Unit and Adult Cystic Fibrosis Center, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
3. Department of Health Sciences, University of Florence, Florence, Italy
4. Department of Internal Medicine and Medical Specialties, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
5. Department of Internal Medicine and Medical Specialties, University of Genoa, Genoa, Italy
6. Department of Medical Sciences, University of Ferrara, Ferrara, Italy
7. Vaccines Medical Department, GSK, Verona, Italy
8. Respiratory Unit, Department of Health of Sciences, ASST Santi Paolo e Carlo, University of Milan, Milan, Italy