Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA. rs3895@cumc.columbia.edu. Present Address: Department of Epidemiology, Columbia University Mailman School of Public Health, 722 West 168th St, Room 705, New York, NY, 10032, USA. rs3895@cumc.columbia.edu. Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA. National AIDS Research Institute, Pune, India. Present Address: National Institute of Research in Tuberculosis, Chennai, India. YR Gaitonde Center for AIDS Research and Education, Chennai, India. UNC Lilongwe, Lilongwe, Malawi. Malawi College of Medicine-Johns Hopkins University Research Project, Blantyre, Malawi. Present Address: Liverpool School of Tropical Medicine, Liverpool, UK. STD/AIDS Clinical Research Laboratory, Instituto de Pesquisa Clinica Evandro Chagas, Fundacao Oswaldo Cruz, Rio de Janeiro, Brazil. Hospital Nossa Senhora de Conceiçã, Porto Alegre, Brazil. Asociacion Civil Impacta Salud y Educacion, Lima, Peru. Department of Medicine, University of Witwatersrand, Johannesburg, South Africa. Durban International Clinical Research Site, Durban University of Technology, Durban, South Africa. University of Zimbabwe Clinical Research Centre, Harare, Zimbabwe. Les Centres GHESKIO, Port-Au-Prince, Haiti. Research Institute for Health Sciences, Chiang Mai, Thailand. Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA. Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA. Present Address: Bill and Melinda Gates Foundation, Seattle, USA. Department of Medicine, Division of Infectious Diseases, University of Colorado School of Medicine, Aurora, CO, USA.