1. Respiratory Care Department, Gregorio Marañón General University Hospital, 28007 Madrid, Spain
2. Department of Public Health and Maternal & Child Health, Faculty of Medicine, Complutense University of Madrid, 28040 Madrid, Spain
3. Madrilenian Health Service, Ministry of Health, 28046 Madrid, Spain
4. Department of Immunology, Laboratory of Neurobiology of Hearing (UCM 910915), Ophthalmology and Otorhinolaryngology, Faculty of Medicine, Complutense University of Madrid, 28040 Madrid, Spain
5. Epi-PHAAN Research Group, School of Medicine, Universidad de Malaga, 29071 Malaga, Spain