[1] Univ N Carolina, Gillings Sch Global Publ Hlth, Dept Epidemiol, Chapel Hill, NC 27515 USA
[2] Duke Univ, Sch Med, Dept Obstet & Gynecol, Durham, NC USA
[3] Univ N Carolina, Gillings Sch Global Publ Hlth, Dept Biostat, Chapel Hill, NC 27515 USA
[4] Becton Dickinson & Co, Sparks, MD USA
[5] North Carolina Cent Univ, Dept Publ Hlth Educ, Durham, NC USA
[6] North Carolina Cent Univ, Dept Biol & Biomed Sci, Durham, NC USA
[7] Univ N Carolina, Sch Med, Dept Microbiol & Immunol, Chapel Hill, NC 27515 USA
[8] Univ N Carolina, Sch Med, Dept Pathol & Lab Med, Chapel Hill, NC 27515 USA
[9] Univ N Carolina, Sch Med, Dept Obstet & Gynecol, Chapel Hill, NC 27515 USA
[10] Univ N Carolina, Lineberger Comprehens Canc Ctr, Chapel Hill, NC 27515 USA