1. 1Center for Microbiology Research, Kenya Medical Research Institute, Kisumu, Kenya
2. 2Department of Obstetrics and Gynaecology, University of Washington, Seattle, WA, USA
3. 3Centre for Clinical Research, Partners in Health and Research Development, Kenya Medical Research Institute, Thika, Kenya
4. 4Centre for Clinical Research, Kenya Medical Research Institute, Nairobi, Kenya
5. 5Department of Global Health, University of Washington, Seattle, WA, USA
6. 6Division of Infectious Disease, Massachusetts General Hospital, Boston, MA, USA