University of Murcia - Paediatric Allergy and Pulmonology Units, University of KwaZulu-Natal - Department of Paediatrics and Child Health, Peking University - Peking University Third Hospital, University of Auckland - Paediatric Department, University of New South Wales (UNSW), EpiLab, Sudan, University of Auckland, University of Auckland - Paediatric Department, University of Auckland, London School of Hygiene & Tropical Medicine, University of London, University of Murcia, University of Murcia, University of KwaZulu-Natal and University of Murcia