[1] Univ Med Ctr Utrecht, Julius Ctr Hlth Sci & Primary Care, NL-3508 GA Utrecht, Netherlands
[2] Univ Med Ctr Utrecht, Wilhelmina Childrens Hosp, Dept Pediat, NL-3508 GA Utrecht, Netherlands
[3] Univ Med Ctr Utrecht, Wilhelmina Childrens Hosp, Dept Otolaryngol, NL-3508 GA Utrecht, Netherlands
[4] Univ Oxford, Inst Hlth Sci, Dept Primary Hlth Care, Oxford, England
[5] Univ Southampton, Dept Primary Med Care, Community Clin Sci Div, Southampton, Hants, England
[6] Aldermoor Hlth Ctr, Southampton, Hants, England
[7] Univ Texas Galveston, Med Branch, Dept Pediat, Ottawa, ON, Canada
[8] Childrens Hosp Eastern Ontario, Div Infect Dis, Dept Pediat, Ottawa, ON K1H 8L1, Canada