1. a Department of Sociology, Psychology and Social Work , University of the West Indies , Mona , Kingston , Jamaica
2. b Centre for Sexual Health and HIV Research , University College London , London , UK
3. c Department of Infectious Disease Epidemiology , Imperial College London , London , UK
4. d Reproductive Health Research Unit , University of Witswatersrand , Johannesburg , South Africa
5. e National Center for HIV/AIDS, Viral Hepatitis, STD and TB Prevention , Centers for Disease Control and Prevention , Atlanta , GA , USA
6. f Academic Department of HIV/GUM , King's College London , London , UK