1 Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland claudia.kuehni@ispm.unibe.ch.
2 Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland Paediatric Respiratory Medicine, Children's University Hospital of Bern, University of Bern, Bern, Switzerland.
3 Primary Ciliary Dyskinesia Centre, University Hospital Southampton NHS Foundation Trust, Southampton, UK NIHR Southampton Respiratory Biomedical Research Unit, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, UK.