1. Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina.
2. Department of Health Behavior, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina.
3. Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina.
4. Department of Obstetrics & Gynecology, University of North Carolina School of Medicine, Chapel Hill, North Carolina.
5. Department of Obstetrics and Gynecology, Duke University School of Medicine, Durham, North Carolina.
6. Department of Microbiology and Immunology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina.
7. Department of Biological and Biomedical Sciences, North Carolina Central University, Durham, North Carolina.
8. Department of Public Health Education, North Carolina Central University, Durham, North Carolina.
9. Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina.