1. Center for International Health Research at Rhode Island Hospital, 55 Claverick Street, Suite 101, Providence, RI 02903, United States of America (USA).
2. Department of Immunology, Research Institute for Tropical Medicine, Manila, Philippines.
3. Division of Neonatology, Department of Pediatrics, Boston University School of Medicine, Boston, USA.
4. Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, England.