University of Exeter, University of Exeter, University of Yaounde I - Yaounde Central Hospital, Medical Research Council/Uganda Virus Research Institute & London School of Hygiene and Tropical Medicine (MRC/UVRI & LSHTM), Uganda Research Unit, University of the Witwatersrand, University of the Witwatersrand, Medical Research Council/Uganda Virus Research Institute & London School of Hygiene and Tropical Medicine (MRC/UVRI & LSHTM), Uganda Research Unit, Makerere University, Saint Francis Hospitals, Sultan Qaboos University, Muhimbili National Hospital, Muhimbili National Hospital, Tanzania NCDs Alliance, University of Yaoundé I, University of KwaZulu Natal, University of KwaZulu Natal, University of Pretoria, Life Groenkloof Hospital, University of Yaounde I - Yaounde Central Hospital, University of Exeter - Institute of Clinical and Biological Science, University of Cincinnati - Department of Pediatrics, University of Washington - Department of Pediatrics, New York University (NYU) - Division of Health Services Research, University of Exeter - Institute of Biomedical and Clinical Science, University of Exeter - Institute of Biomedical and Clinical Science, University of Colorado at Denver - Department of Epidemiology, University of Exeter - Institute of Biomedical and Clinical Science, University of Exeter - Institute of Biomedical and Clinical Science, National Health Laboratory Services (NHLS) - Department of Chemical Pathology, MRC/UVRI & LSHTM Uganda Research Unit, University of Yaounde I - Department of Internal Medicine and Specialities and University of Exeter - Institute of Clinical and Biological Science