1. Unit of Clinical Epidemiology, Assistance Publique-Hôpitaux de Paris, CHU Robert Debré, Université Paris Diderot, Sorbonne Paris-Cité, INSERM U1123 and CIC-EC 1426, Paris, France
2. Pediatric Pneumology and Allergic Diseases Unit, Assistance Publique-Hôpitaux de Paris, CHU Robert Debré, Université Paris Diderot, Sorbonne Paris-Cité, Paris, France
3. Pediatric Migraine and Neurovascular Diseases Unit, Assistance Publique-Hôpitaux de Paris, CHU Robert Debré, Université Paris Diderot, Sorbonne Paris-Cité, INSERM U1141, Paris, France
4. Department of Pediatrics, Luigi Sacco Hospital, Università degli Studi di Milano, Milan, Italy
5. Department of Pediatrics, Azienda ospedaliero-universitaria Santa Maria della Misericordia di Udine, Italy
6. Basildon University Hospital, Essex, UK
7. Department of Pediatric Emergency Care,Assistance Publique-Hôpitaux de Paris, CHU Robert Debré, Université Paris Diderot, Sorbonne Paris-Cité, Paris, France