1. Medical University, Department of Pulmonary Diseases, Hospital for Lung Disease "St. Sofia" - Children's Clinic, Sofia, Bulgaria.
2. Department of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, Australia.
3. Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, Sydney, Australia.
4. State University of New York, Upstate Medical University, Syracuse (NY) USA.
5. Barts Health NHS Trust, Royal London Hospital, Division of Infection, London, United Kingdom.
6. Blizard Institute, Barts and the London School of Medicine and Dentistry, Centre for Primary Care and Public Health, London, United Kingdom.
7. Servizio di Epidemiologia Clinica delle Malattie Respiratorie, Istituti Clinici Scientifici Maugeri - IRCCS - Tradate, Italia.
8. University College of London, Institute for Global Health, London, United Kingdom.
a. http://orcid.org/0000-0002-3347-2798; b. http://orcid.org/0000-0001-8321-9814; c. http://orcid.org/0000-0002-1603-4630;
d. http://orcid.org/0000-0003-3404-2690; e. http://orcid.org/0000-0001-8117-0607; f. http://orcid.org/0000-0001-9424-6551;
g. http://orcid.org/0000-0002-2597-574X; h. http://orcid.org/0000-0002-8887-8795