1. Pediatric Infectious Disease Unit, Department of Health Science, Anna Meyer Children‘s University Hospital, University of Florence, Florence, Italy
2. Department of Health Sciences, University of Florence, Florence, Italy
3. Pediatric Clinic, IRCCS Policlinico “S. Matteo” Foundation, University of Pavia, Pavia, Italy
4. Neonatal intensive care unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
5. Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy