[1] Univ Udine, Acad Hosp Santa Maria Misericordia, Dept Med DMED, Div Paediat, Udine, Italy
[2] Inst Maternal & Child Hlth IRCCS Burlo Garofolo, WHO Collaborating Ctr Maternal & Child Hlth, Trieste, Italy
[3] IRCCS Meyer Childrens Univ Hosp, Dept Pediat Emergency Med, Florence, Italy
[4] Univ Padua, Dept Womens & Childrens Hlth, Padua, Italy
[5] Treviso Hosp, Dept Pediat, Treviso, Italy
[6] Univ Bari, Pediat Hosp Giovanni XXIII, Dept Pediat, Bari, Italy
[7] Childrens Hosp G Cristina, ARNAS Civ Cristina Benfratelli, Pediat Emergency Unit, Dept Pediat, Palermo, Italy
[8] Santa Maria Croci Hosp, Dept Pediat, Ravenna, Italy
[9] Cannizzaro Emergency Hosp, CA Pediat & Pediat Emergency Room Unit, Catania, Italy
[10] AO SS Antonio & Biagio & Cesare Arrigo, Children Hosp, Pediat & Pediat Emergency Unit, Alessandria, Italy
[11] Carlo Poma Hosp, Dept Pediat, Mantua, Italy
[12] Sapienza Univ Rome, Santa Maria Goretti Hosp, Dept Pediat, Latina, Italy
[13] WHO, Dept Maternal Newborn Child & Adolescent Hlth & Ag, Geneva, Switzerland
[14] Inst Maternal & Child Hlth IRCCS Burlo Garofolo, Dept Paediat, Trieste, Italy
[15] Univ Trieste, Trieste, Italy
[16] London Sch Hyg & Trop Med, Fac Epidemiol & Populat Hlth, Maternal Adolescent Reprod & Child Hlth Care Ctr, London, England