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University of Florence - Immunology Unit, University of Florence - Immunology Unit, University of Genova - Department of Health Sciences, University of Padua - Department of Cardiac, Thoracic, Vascular Sciences and Public Health, A.O.U. City of Health and Science - S.C. Microbiology and virology laboratory, A.O.U. City of Health and Science - S.C. Microbiology and virology laboratory, - Department of Health Promotion, Maternal-Infantile, Internal and Specialized Medicine of Excellence “G. D'Alessandro, University of Padua - Department of Woman’s and Child’s Health, Regional epidemiology reference service for the surveillance, prevention and control of infectious diseases- Local Health Unit of Alessandria, University of Foggia - Department of Medical and Surgical Sciences, University of Florence - Immunology Unit, University of Genova - Department of Health Sciences, University of Foggia - Department of Medical and Surgical Sciences, University of Florence - Laboratory of Immunology and Molecular Microbiology, University of Foggia - Department of Medical and Surgical Sciences, University of Florence - Immunology Unit, Regional Directorate of Prevention, Food Safety, Veterinary, Public Health-Veneto Region, Padua University and Hospital - Women and Child Health Department, - Department of Health Promotion, Maternal-Infantile, Internal and Specialized Medicine of Excellence “G. D'Alessandro, Government of the United Kingdom - National Infection Service, University of Florence - Immunology Unit and Independent

Meyer Children’s University Hospital - Pediatric Unit, Meyer Children’s University Hospital - Pediatric Unit, San Jacopo Hospital, San Donato Hospital, Pisa University - Pisa University Hospital, Italian Federation of Pediatricians (FIMP) - Tuscany Regional Section, San Jacopo Hospital, Santo Stefano Hospital - Pediatric and Neonatology Unit, University of Siena - Pediatric Unit, Azienda Ospedaliero-Universitaria Careggi, University of Siena - Department of Molecular and Developmental Medicine, University of Florence - Department of Statistics, Computer Science, Applications, Pisa University - Pisa University Hospital, San Donato Hospital, Santa Maria Annunziata Hospital, University of Florence - Laboratory of Immunology and Molecular Microbiology, Italian Federation of Pediatricians (FIMP) - Tuscany Regional Section, Pisa University - Pisa University Hospital, University of Siena - Department of Molecular and Developmental Medicine, University of Florence - Immunology Unit, Santa Maria Annunziata Hospital, University of Siena - Pediatric Unit, Santa Maria Annunziata Hospital, University of Siena - Pediatric Unit, University of Siena - Pediatric Unit, Santo Stefano Hospital - Pediatric and Neonatology Unit, University of Florence - Immunology Unit and University of Florence - Paediatric and Liver Unit