1. Institute of Social and Preventive Medicine University of Bern Bern Switzerland
2. Graduate School for Cellular and Biomedical Sciences University of Bern Bern Switzerland
3. Division of Paediatric Respiratory Medicine and Allergology, Department of Paediatrics Inselspital, Bern University Hospital, University of Bern Bern Switzerland
4. Department of Respiratory Medicine University Children's Hospital Zurich and Childhood Research center, University of Zurich Zurich Switzerland
5. University Children's Hospital Basel (UKBB) Basel Switzerland
6. PEDNET, Paediatric Clinical Trial Unit Children's University Hospital of Bern, University of Bern Bern Switzerland