1. Department of Neonatology, IdiPaz Foundation La Paz University Hospital Madrid Spain
2. Department of Neonatology Severo Ochoa University Hospital Madrid Spain
3. Respiratory Virus and Influenza Unit National Center of Microbiology Madrid Spain
4. Department of Pediatric Infectious Diseases, IdiPaz Foundation Traslational Research Network in Pediatric Infectious Diseases (RITIP) Madrid Spain
5. TEDDY Network (European Network of Excellence for Pediatric Clinical Research) Pavia Italy
6. Department of Pediatric Infectious Diseases, IdiPaz Foundation La Paz University Hospital Madrid Spain