1. Division of Paediatric Infectious Diseases, Department of Woman and Child Health, University Hospital of Padua, Padua, Italy
2. Department of Pediatrics, Woman and Child Hospital, University of Verona, Verona, Italy
3. Neonatal Intensive Care Unit, Department of Women's and Children's Health, University Hospital of Padua, Padua, Italy
4. Health Services Unit, KEMRI-Wellcome Trust Research Programme, Nairobi, Kenya
5. Department of Paediatrics, University of Nairobi, Nairobi, Kenya
6. Nuffield Department of Medicine, University of Oxford, Oxford, Oxfordshire, United Kingdom