1. School of Economics and Management, Cattaneo University-LIUC, Castellanza, Italy
2. Centre for Health Economics, University of York, York, UK
3. Institute of Public Health, Section of Hygiene, Catholic University of the Sacred Heart, Rome, Italy
4. Department of Health Sciences, University of Florence, Florence, Italy
5. Department of Health Sciences, University of Genoa, Genoa, Italy
6. Inter-University Centre for Research on Influenza and Other Transmitted Diseases (CIRI-IT), Genoa, Italy