Independent, King’s College London - Department of Women and Children’s Health, Centro de Investigação em Saúde da Manhiça (CISM), King’s College London - Department of Women and Children’s Health, University of British Columbia (UBC) - Department of Pediatrics, British Columbia Children's Hospital Research Institute, London School of Hygiene & Tropical Medicine - Medical Research Council Unit The Gambia, University of Oxford - Nuffield Department of Women's and Reproductive Health, Aga Khan University, London School of Hygiene & Tropical Medicine - Medical Research Council Unit The Gambia, Centro de Investigação em Saúde da Manhiça (CISM), King’s College London - Department of Women and Children’s Health, Aga Khan University, Zuri Nzilani Foundation, London School of Hygiene & Tropical Medicine - Medical Research Council Unit: The Gambia, Aga Khan University - Centre of Excellence in Women and Child Health, University of British Columbia (UBC), London School of Hygiene & Tropical Medicine - Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine - Department of Infectious Disease Epidemiology, King’s College London and King’s College London - Department of Women and Children’s Health