[1] Inselspital Bern, Dept Pediat, Div Resp Med, Bern, Switzerland
[2] Univ Bern, Bern, Switzerland
[3] Aristotle Univ Thessaloniki, Hippokration Hosp, Pediat Dept 3, Thessaloniki, Greece
[4] Univ Childrens Hosp Basel, UKBB, Dept Pediat Pulmonol, Basel, Switzerland
[5] CHU Vaudois, Resp Unit, Dept Pediat, Lausanne, Switzerland
[6] Univ Lausanne, Lausanne, Switzerland
[7] Univ Childrens Hosp Zurich, Dept Pediat Pulmonol, Zurich, Switzerland