Regional Hospital San Camillo-Forlanini - Operative Unit of Pediatrics, Sapienza University of Rome - Department of Maternal, Infantile, and Urological Sciences, Regional Hospital San Camillo-Forlanini - Operative Unit of Pediatrics, National Institute of Health (Italy) - National Centre for Disease Prevention and Health Promotion, Regional Hospital San Camillo-Forlanini - Laboratory of Microbiology and Virology, L’altrastatistica srl - Consultancy & Training, Biostatistics Office, University of Rome I - NESMOS Department, Regional Hospital San Camillo-Forlanini - Laboratory of Microbiology and Virology, University of Rome I - NESMOS Department, Sapienza University of Rome - Department of Maternal, Infantile, and Urological Sciences and National Institute of Health (Italy)