Centre for the AIDS Programme of Research in Africa (CAPRISA), University of KwaZulu- Natal, University of Washington, University of Oxford - Nuffield Department of Primary Care Health Sciences, eThekwini Municipality Health Unit, University of Washington, Washington University in St. Louis, Centre for the AIDS Programme of Research in South Africa (CAPRISA), Centre for the AIDS Programme of Research in South Africa (CAPRISA), Centre for the AIDS Programme of Research in South Africa (CAPRISA), Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal - Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of Washington, Bethesda - MD, University of KwaZulu-Natal, Fred Hutchinson Cancer Research Center, University of KwaZulu-Natal - Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal - Centre for the AIDS Programme of Research in South Africa (CAPRISA)University of the Witwatersrand - South African Medical Research Council, University of Washington, University of KwaZulu-Natal, University of California, San Francisco (UCSF) - Division of HIV, Infectious Diseases and Global Medicine, University of KwaZulu-Natal, Chiang Mai University and University of Washington - Department of Global Health