1. Department of Preventive Medicine, Workers Health Protection and Promotion Unit, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, ITALY
2. Department of Clinical Science and Community Health DISCCO, University of Milan, Milano, ITALY
3. Department of Clinical Chemistry and Microbiology, Bacteriology and Virology Units
4. Ospedale Maggiore Policlinico, Milan, ITALY
5. Pediatric Intermediate Care Unit, Fondazione IRCCS Ospedale Cà Granda-Ospedale Maggiore, Milano, ITALY