London School of Hygiene & Tropical Medicine - Vaccines and Immunity Theme, London School of Hygiene & Tropical Medicine - Vaccines and Immunity Theme, London School of Hygiene & Tropical Medicine - Vaccines and Immunity Theme, London School of Hygiene & Tropical Medicine - Vaccines and Immunity Theme, London School of Hygiene & Tropical Medicine - Medical Research Council Unit The Gambia, London School of Hygiene & Tropical Medicine - Vaccines and Immunity Theme, London School of Hygiene & Tropical Medicine - Vaccines and Immunity Theme, Université Libre de Bruxelles (ULB) - Molecular Bacteriology Laboratory, London School of Hygiene & Tropical Medicine - Vaccines and Immunity Theme, University of Sheffield, University of Sheffield - Department of Infection, Immunity & Cardiovascular Disease, London School of Hygiene & Tropical Medicine - Vaccines and Immunity Theme, London School of Hygiene & Tropical Medicine - Medical Research Council Unit: The Gambia, London School of Hygiene & Tropical Medicine - Centre for Mathematical Modelling of Infectious Diseases, Université Libre de Bruxelles (ULB) - Molecular Bacteriology Laboratory, University of Sheffield - Department of Infection, Immunity & Cardiovascular Disease, London School of Hygiene & Tropical Medicine - Department of Clinical Research and Independent