1. Department of Obstetrics and Gynaecology, University of Zimbabwe College of Health Sciences, Harare, Zimbabwe;
2. Department of Medical Microbiology, University of Zimbabwe College of Health Sciences, Harare, Zimbabwe;
3. University of Zimbabwe College of Health Sciences Clinical Trials Research Centre (UZCHS-CTRC), University of Zimbabwe College of Health Sciences, Harare, Zimbabwe;
4. Program Quality Improvement, Elizabeth Glaser Pediatric AIDS Foundation, Harare, Zimbabwe;
5. Department of Medicine, UCSF School of Medicine, Med Sci San Francisco, CA, USA