[1] Univ Botswana, Fac Med, Dept Obstet & Gynecol, Gaborone, Botswana
[2] Ctr Dis Control & Prevent, Natl Ctr Immunizat & Resp Dis, Atlanta, GA USA
[3] Univ Botswana, Fac Med, Off Res & Grad Studies, Gaborone, Botswana
[4] Botswana Univ Maryland, BUMMHI, Sch Med, Gaborone, Botswana
[5] Ctr Dis Control & Prevent, Natl Ctr Emerging Zoonot & Infect Dis, Atlanta, GA USA
[6] Botswana Minist Hlth & Wellness, Natl Hlth Lab, Gaborone, Botswana
[7] Botswana Harvard AIDS Inst Partnership, Gaborone, Botswana
[8] Univ Edinburgh, MRC Ctr Reprod Hlth, Edinburgh, Midlothian, Scotland
[9] Beth Israel Deaconess Med Ctr, Dept Obstet & Gynecol, Boston, MA USA