1 Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland.
2 Paediatric Respiratory Medicine, Children's University Hospital of Bern, University of Bern, Bern, Switzerland.
3 Paediatric Dept of Allergy and Lung Diseases, Oslo University Hospital, Oslo, Norway.
4 Division of Pediatric Pulmonology, Allergology, and Endocrinology, Dept of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.
5 School of Clinical and Experimental Sciences, University of Southampton Faculty of Medicine, Southampton, UK.
6 Respiratory Physiology Laboratory, Medical School, University of Cyprus, Nicosia, Cyprus.
7 Dept of General Pediatrics, University Hospital Münster, Münster, Germany.
8 Primary Ciliary Dyskinesia Centre, NIHR Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton, UK.
9 Dept of Pediatric Pulmonology, Immunology and Critical Care Medicine, Charité-Universitätsmedizin, Berlin, Germany.