1. Heim Pal National Paediatric Institute, Budapest, Hungary
2. Department of Preventive Medicine, Poznan University of Medical Sciences, Poznan, Poland
3. Department of Paediatrics, University Hospital Centre, Zagreb, Croatia
4. Department of Paediatrics, Riga Stradins University, Riga, Latvia
5. Clinic of Children’s Diseases, Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
6. Vilnius University Hospital Santaros Klinikos, Vilnius, Lithuania
7. Department of Infectious Diseases, University Medical Centre Ljubljana, Ljubljana, Slovenia
8. Hospital for Infectious Diseases, Medical University of Sofia, Sofia, Bulgaria
9. Clinic of Infectious Diseases and Dermatovenerology, Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
10. Mother and Child Care Department, University of Medicine and Pharmacy ‘Iuliu Hațieganu’, Cluj-Napoca, Romania
11. Faculty of Public Health, Slovak Medical University, Bratislava, Slovakia
12. Jessenius Faculty of Medicine in Martin, Comenius University, Bratislava, Slovakia
13. University Hospital for Infectious Diseases, University of Zagreb, School of Medicine, Zagreb, Croatia
14. Global Medical Affairs, MSD Polska Sp. z. o.o., Warsaw, Poland
15. Center for Observational and Real-World Evidence (CORE), Merck & Co., Inc., Kenilworth, NJ, USA