1. Paediatric Infectious and Tropical Diseases Department, Hospital Universitario La Paz, Hospital La Paz Institute for Health Research (IdiPAZ Foundation), 28046 Madrid, Spain
2. Department of Neonatology, Hospital Universitario La Paz, Hospital La Paz Institute for Health Research (IdiPAZ Foundation), 28046 Madrid, Spain
3. Respiratory Viruses and Influenza Unit, National Centre of Microbiology, 28222 Madrid, Spain
4. Centro de Investigación Biomédica en Red en Epidemiología y Salud Pública (CIBERESP), Instituto de Salud Carlos III, 28222 Madrid, Spain
5. Centro de Investigación Biomédica en Red en Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28222 Madrid, Spain
6. Traslational Research Network in Pediatric Infectious Diseases (RITIP), Universidad Autónoma de Madrid, 28049 Madrid, Spain