[1] Rigshosp, Dept Otorhinolaryngol Head & Neck Surg & Audiol, DK-2100 Copenhagen, Denmark
[2] Rigshosp, Dept Clin Microbiol, DK-2100 Copenhagen, Denmark
[3] Univ Copenhagen, Inst Microbiol & Immunol, DK-1168 Copenhagen, Denmark
[4] Rigshosp, Copenhagen CF Ctr, DK-2100 Copenhagen, Denmark
[5] Rigshosp, Dept Paediat & Adolescent Med, Paediat Pulm Serv, DK-2100 Copenhagen, Denmark
[6] Univ Liverpool, Dept Publ Hlth & Policy, Liverpool L69 3BX, Merseyside, England
[7] Univ Erlangen Nurnberg, Dept Med Informat Biometry & Epidemiol, Erlangen, Germany