1. Hôpital Necker-Enfants Malades; Service de Pédiatrie; Paris France
2. Department of Pediatrics and Adolescent Medicine; American University of Beirut; Beirut Lebanon
3. Vaccine Research; Pfizer Ltd; Tadworth Berkshire UK
4. RHUH; Rafic Hariri University Hospital; Beirut Lebanon
5. University of Alabama at Birmingham; Birmingham; Alabama
6. Pediatric Cairo University Hospital (Abu Elreesh - Almoneera); Egypt
7. Hematology unit; Children Hospital; Ain Shams University; Cairo Egypt
8. Ospedale San Luigi Gonzaga; Orbassano; Torino University; Italy
9. Vanderbilt University Medical Center; Nashville Tennessee
10. Evelina Children's Hospital; St Thomas' Hospital; London UK
11. King's College Hospital; London UK
12. Vaccine Institute; St Georges; University of London; London UK
13. Royal London Hospital; London; UK
14. Children's Hospital at Montefiore; Bronx New York
15. King Faisal Specialist Hospital and Research Centre; Riyadh; Saudi Arabia
16. Unità Operativa di Epidemiologia Ospedale Bambino Gesù; Roma; Italy
17. Vaccines; Pfizer Inc; Collegeville Pennsylvania
18. Vaccine Research; Pfizer Inc; Pearl River New York