1. Department of Clinical Virology, School of Medicine, University of Crete, Heraklion 71003, Greece
2. Division of Asthma, Allergy and Lung Biology, King's College London, London SE5 9RS, UK
3. 1st Department of Paediatrics, ‘Aghia Sophia’ Children's Hospital, Athens Medical School, National and Kapodistrian University of Athens, Athens 115 27, Greece