1. Department of Pediatric and Adolescent Medicine, Stavanger University Hospital, Stavanger, Norway;
2. Department of Clinical Science, University of Bergen, Bergen, Norway;
3. Department of Research, Section of Biostatistics, Stavanger University Hospital, Stavanger, Norway;
4. Department of Medical Microbiology, Hospital of Southern Norway Trust, Kristiansand, Norway;
5. Department of Pediatric and Adolescent Medicine, Hospital of Southern Norway Trust, Kristiansand, Norway;
6. Department of Pediatric and Adolescent Medicine, Haukeland University Hospital, Bergen, Norway