Biomedical Research & Training Institute - The Health Research Unit Zimbabwe, London School of Hygiene & Tropical Medicine - Faculty of Infectious and Tropical Diseases, Biomedical Research & Training Institute - The Health Research Unit Zimbabwe, Ludwig Maximilian University of Munich (LMU), Instituto Nacional de Saude, Mbeya Medical Research Center, Biomedical Research and Training Institute, London School of Hygiene & Tropical Medicine - Faculty of Infectious and Tropical Diseases, University College London, Bulawayo City Health, East, Central, and Southern Africa-Health Community, University of Tübingen - Institute of Tropical Medicine, Instituto Nacional de Saúde., National Institute for Medical Research (NIMR), Biomedical Research and Training Institute, Yenepoya College - Center for Nutrition Studies, Ludwig Maximilian University of Munich (LMU), University College London, Ludwig Maximilian University of Munich (LMU) and London School of Hygiene & Tropical Medicine - Department of Clinical Research