Background Vaginal dysbiosis is a risk factor for sexually transmitted infections (STI) and HIV in young women, and is highly prevalent in Africa. We sought to describe the microbiota of younger African women, before engaging in sexual behavior.

Methods Adolescent girls aged 16–21 were recruited in Thika, Kenya. Eligible participants were HIV and HSV-2 seronegative, and reported sexual naiveté or one lifetime sexual partner. Nugent score was determined from vaginal Gram stains. Girls were tested for Neisseria gonorrhea (NG), Chlamydia trachomatis (CT), and Trichomonas vaginalis (TV). Chi-square testing was used to compare BV with other variables.

Results We enrolled 400 girls with a median age of 18.6 years (range 16–21). The majority (322 girls, 80.5%) reported no history of sexual intercourse, while 78 (19.5%) reported sex with 1 lifetime partner. Reported sexual partners were older, with median age of 22 years (IQR 19–25). At enrollment, 375 girls had vaginal Gram stains: 338 girls (90%) had a normal Nugent score of 0-3. BV (Nugent score ≥7) was uncommon (21 girls, 5.6%). Girls with BV were older (median age 19.3, IQR 17.9–20.3) than girls with Nugent score 0-3 (median age 18.6, IQR 17.6–19.3) and Nugent score 4-6 (median age 18.6, 17.9–19.8). Of 373 girls with STI testing, 49 girls were diagnosed with STIs and 7 girls had both STI and BV. BV was significantly associated with self-reported sexual intercourse: 52% of girls with Nugent score ≥7 reported prior sex, compared to 18% of those with Nugent score 0-3 (p = 0.001).

Conclusion Kenyan adolescent girls in a low-risk cohort have Lactobacillus-dominated vaginal microbiota, and only 5.6% of girls had evidence of BV. BV was found more often in girls who self-reported sexual intercourse. Interventions to prevent the onset of vaginal dysbiosis could be beneficial for African women.

Disclosure No significant relationships.