1. Sach′s Children and Youth Hospital South General Hospital Stockholm Sweden
2. Department of Medicine Clinical Epidemiology Unit Karolinska Institutet Stockholm Sweden
3. Department of Otorhinolaryngology Karolinska University Hospital Stockholm Sweden
4. Department of Clinical Science, Intervention and Technology (CLINTEC) Division of Ear, Nose‐ and Throat Diseases Karolinska Institutet Stockholm Sweden
5. Department of Radiology Karolinska University Hospital Stockholm Sweden
6. Astrid Lindgren Children′s Hospital Karolinska University Hospital Stockholm Sweden
7. Public Health Agency of Sweden Solna Sweden
8. Department of Public Health Sciences Division of Global Health Karolinska Institutet Stockholm Sweden