1. Institute of Social and Preventive Medicine University of Bern Bern Switzerland
2. Graduate School for Health Sciences University of Bern Bern Switzerland
3. Department of Intensive Care and Neonatology, Children's Research Center, University Children's Hospital Zurich University of Zurich Zurich Switzerland
4. The University Children's Hospital Basel Basel Switzerland
5. Division of Paediatric Respiratory Medicine and Allergology, Department of Paediatrics, Inselspital, Bern University Hospital University of Bern Bern Switzerland
6. Department of Respiratory Medicine, University Children's Hospital Zurich and Children's Research Center University of Zurich Zurich Switzerland