1. Hygiene Unit, San Martino Polyclinic Hospital-IRCCS for Oncology and Neurosciences, Genoa, Italy
2. Department of Health Sciences (DISSAL), University of Genoa, Genoa, Italy
3. Interuniversity Research Center on Influenza and Other Transmissible Infections (CIRI-IT), Genoa, Italy
4. CSL Seqirus, Global Clinical Safety & Pharmacovigilance, Melbourne, Australia