1. Department of Global Health, University of Washington, Seattle, WA, USA
2. Centre for Clinical Research, Kenya Medical Research Institute, Nairobi, Kenya
3. Division of Global HIV and TB, United States Centers for Disease Control and Prevention, Nairobi, Kenya
4. Department of Obstetrics and Gynaecology, Kenyatta National Hospital, Nairobi, Kenya
5. Fred Hutchinson Cancer Research Center, Seattle, WA, USA
6. Ministry of Health, National AIDS and STI Control Programme, Nairobi, Kenya