1. Centre for Global Health Research, Kenya Medical Research Institute (KEMRI)/CDC Program, Kisumu, Kenya
2. Centers for Disease Control and Prevention, Office of Infectious Diseases, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Division of HIV/AIDS Prevention, Atlanta, GA, USA
3. School of Public Health, Faculty of Community and Health Sciences, University of the Western Cape, Cape Town, South Africa