Columbia University - Department of Biostatistics, Columbia University - Department of Biostatistics, Rakai Health Science Program, Rakai Health Science Program, Columbia University - Heilbrunn Department of Population and Family Health, Rakai Health Science Program, Rakai Health Science Program, Columbia University - Heilbrunn Department of Population and Family Health, Columbia University - Heilbrunn Department of Population and Family Health, Columbia University - Department of Biostatistics, Rakai Health Science Program, Columbia University - Mailman School of Public Health, affiliation not provided to SSRN, Columbia University - Heilbrunn Department of Population and Family Health, Washington University in St. Louis - Brown School, Washington University in St. Louis - Brown School, Rakai Health Science Program, Johns Hopkins University - Department of Epidemiology, Johns Hopkins University - Department of Medicine, Rakai Health Science Program and Makerere University - College of Health Sciences