1. Department of Pediatric Respiratory Medicine and Allergy; Emma Children's Hospital; Academic Medical Centre; Amsterdam The Netherlands
2. Clinical and Experimental Sciences Academic Unit; Faculty of Medicine; University of Southampton; Southampton UK
3. NIHR Respiratory Biomedical Research Unit; University Hospital Southampton NHS Foundation Trust; Southampton UK
4. Institute of Social Medicine; Epidemiology and Health Economics; Charité University Medical Centre; Berlin Germany
5. Department of Paediatric Pneumology and Immunology; Charité University Medical Centre; Berlin Germany
6. German Agency for Quality in Medicine; Berlin Germany
7. Faculty of Medicine; Vilnius University; Vilnius Lithuania
8. Sofia Children's University Hospital; Madrid Spain
9. University Hospital La Paz; Madrid Spain
10. Department of Allergy; Second Paediatric Clinic; University of Athens; Athens Greece
11. Neonatal Division; Second Department of Obstetrics and Gynaecology; University of Athens; Athens Greece
12. Division of Allergy; Department of Pediatrics; Pediatric Hospital Bambino Gesù; Rome Italy
13. Department of Immunology; Landspitali-The National University Hospital of Iceland; Reykjavik Iceland
14. Children's Hospital; Landspitali-The National University Hospital of Iceland; Reykjavik Iceland
15. Department of Pediatrics, Preventive Cardiology and Immunology; Medical University of Łódź; Łódź Poland
16. Department of Pediatrics, Immunology and Nephrology; Department of Pediatrics, Clinical Immunology and Cardiology; Polish Mother's Health Centre Research Institute Łódź; Medical University of Łódź; Łódź Poland
17. Institute of Inflammation and Repair; Manchester Academic Health Science Centre; Manchester Institute of Biotechnology; University of Manchester; Manchester UK
18. Institute of Clinical Epidemiology and Biometry; University of Würzburg; Würzburg Germany