Institution: | 1. Copenhagen Prospective Studies on Asthma in Childhood, Health Sciences, University of Copenhagen, Naestved Hospital, Naestved, Denmark.; 2. Copenhagen Prospective Studies on Asthma in Childhood, Health Sciences, University of Copenhagen, Copenhagen University Hospital, Gentofte, Copenhagen, Denmark.; 3. Department of Microbiological Surveillance and Research, Statens Serum Institut, Copenhagen, Denmark.; UCL Institute of Child Health, University College London, United Kingdom, |