Bacterial vaginosis may increase the risk for HIV acquisition in women who use hormonal contraception, according to results recently published in AIDS. The researchers found that women who had bacterial vaginosis who also had been receiving injectable or oral contraception medications were at increased risk of contracting HIV from their partners.
The study included serodiscordant couples enrolled in an open longitudinal cohort in Lusaka, Zambia, from 1994 to 2012. The researchers analyzed a total of 564 couples in which the male partner was diagnosed with HIV when a quarterly genital tract examination and HIV testing were performed. The researchers recorded the contraceptive method used since last visit at baseline and at follow-up visits, with types of contraceptives categorized as implant, injectable, or oral contraception vs nonhormonal. The primary outcome was incident HIV infection among female participants.
The 564 couples contributed 1137.2 couple-years of observation. During that time, 106 female participants became HIV infected. Bacterial vaginosis was detected at 648 (15.5%) of 4183 study visits, and 22 of the HIV infections occurred during intervals where bacterial vaginosis was detected at the visit before the infection.
During intervals where bacterial vaginosis was detected, HIV infection rates per 100 couple-years were 8.3, 20.8, and 31.0 for nonhormonal, injectable, and oral contraceptive pill users, respectively. During intervals without bacterial vaginosis detected, HIV infection rates per 100 couple-years were 8.2, 9.7, and 12.3 for nonhormonal, injectable, and oral contraceptive pill users, respectively. No participants using implants became HIV infected.
The bacterial vaginosis-positive model indicates a significant increase in incident HIV among participants using injectables (adjusted hazard ratio, 6.55; 95% CI, 1.14-37.77) and oral contraceptive pills (adjusted hazard ratio, 5.20; 95% CI, 1.68-16.06) compared with participants who did not use hormonal contraceptives. Hormonal contraceptives did not increase the hazard of HIV acquisition in bacterial vaginosis-negative models.
Taken together, these findings suggest that hormonal contraception, and specifically oral contraceptive pills and injectable contraception, may influence risk for HIV acquisition. “[P]eriodic testing and treatment among asymptotic women at high-risk for HIV and counseling women on the symptoms of [bacterial vaginosis] may be important preventative strategies,” the researchers concluded.
Haddad LB, Wall KM, Kilembe W, et al. Bacterial vaginosis modifies the association between hormonal contraception and HIV acquisition [published online January 13, 2018]. AIDS. doi:10.1097/QAD.0000000000001741