1. Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
2. Pakistan Health Research Council, Islamabad, Pakistan
3. TEPHINET, Centers for Disease Control and Prevention, Atlanta, GA, USA
4. Aga Khan University, Karachi, Pakistan
5. National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
6. National AIDS Control Programme, Islamabad, Pakistan
7. Division of Global Public Health, Department of Medicine, University of California San Diego, CA, USA