1. Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
2. Department of Population, Family, and Reproductive Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
3. CARE, Yaounde, Cameroon
4. CARE, New York, NY, USA
5. Metabiota, Inc., Yaounde, Cameroon
6. Groupe Technique Central du Comité National de Lutte contre le SIDA, Yaoundc, Cameroon
7. Division of Operations Research, Ministry of Health, Yaounde, Cameroon