From the *Northfield Health Centre, Birmingham, United Kingdom; †Universita di Genova Istituto di Igiene e Medicina Preventiva Dipartimento di Scienze della Salute, Genova, Italy; ‡Universitätsklinikum Berlin Charité Pneumologie und Immunologie, Berlin, Germany; §Jorvi Hospital, Espoo, Finland; ¶Shaare Zedek Medical Center, Jerusalem, affiliated to the Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel; ∥General Hospital of Arta Paediatric department, Arta, Greece; #Stavanger University Hospital, Stavanger, Norway; **Hospital Severo Ochoa de Leganes Servicio de Pediatria, Leganes, Spain; ††Private practice, Brussels, Belgium; ‡‡Centro Hospitalar de V.N. de Gaia Consulta externa de Alergologia Pediatrica, Vila Nova de Gaia, Portugal; §§University Children's Hospital, Basel, Switzerland; ¶¶Wyeth Vaccines Research, Louvain-la-Neuve, Belgium; ##Wyeth Vaccines Research, Pearl River, NY.