1. Department of Infectious, Parasitic & Immuno-mediated Diseases, Istituto Superiore di Sanità, Rome, Italy
2. Epidemiology and Preventive Medicine Unit, Central Tuscany Health Authority, Florence, Italy
3. Health Agency of Tuscany, Florence, Italy
4. National Center for Epidemiology, Surveillance and Health Promotion - Istituto Superiore di Sanità, Rome, Italy
5. Ministry of Health, Directorate-General of health prevention, Rome, Italy