1. Department of Epidemiology & Biostatistics, University of California, San Francisco, CA, USA.
2. Institute for Global Health Sciences, University of California, San Francisco, CA, USA.
3. Center for AIDS Prevention Studies, University of California, San Francisco, CA, USA.
4. Navrongo Health Research Centre, Navrongo, Ghana.
5. Department of Family Health Care Nursing, University of California, San Francisco, CA, USA.
6. Tamale Teaching Hospital, Tamale, Ghana.
7. Department of Population, Family and Reproductive Health, School of Public Health, University of Ghana, Accra, Ghana.
8. Policy Planning Monitoring and Evaluation Division, Ghana Health Service, Accra, Ghana.