[1] Charite Univ Med Berlin, Humboldt Univ, Dept Pediat Pneumol & Immunol, D-13353 Berlin, Germany
[2] Univ London Imperial Coll Sci Technol & Med, Dept Pediat, London, England
[3] Royal Childrens Hosp, Murdoch Childrens Res Inst, Melbourne, Vic, Australia
[4] UCB Pharma SA, R&D, Clin Epidemiol & Outcomes Res, Braine Lalleud, Belgium