Clinical and Public Health Microbiology

Improving HIV Prevention Strategies for Women

More than one million women contract HIV every year, and the majority of these new infections occur in young women in sub-Saharan Africa.  Trials of preventive tenofovir retroviral microbicide gels in this population have produced widely varying results, unlike trials of the same products in men that produce consistent and effective results.  The authors wanted to determine what role vaginal flora play in these outcomes, so they analyzed the vaginal flora of 688 HIV-negative women who took part in the CAPRISA (Centre for the AIDS Program of Research in South Africa) 004 trial of daily or coital vaginally-applied tenofovir gel.  Participants were chosen from both the active and placebo arms of the study, and the results were adjusted for levels of adherence.  The researchers found two principal environments: one dominated by Lactobacillus (61.5%, n=423) and one dominated by the gram-negative bacteria Gardnerella vaginalis (38.5%, n=265).  Tenofovir reduced the incidence of HIV by 61% in the Lactobacillus-dominant group and 18% in the Gardnerella-dominant group, proving that tenofovir gel efficacy was directly affected by the type of flora in the vaginal compartment.  The authors hope their results will be used to improve HIV prevention strategies for women.

Article:   Science 356, 938-945 (2017).


Klatt, N. R., Cheu, R., Birse, K., Zevin, A. S., Perner, M., Noël-Romas, L., . . . Burgener, A. D. (2017). Vaginal bacteria modify HIV tenofovir microbicide efficacy in African women. Science, 356(6341), 938-945. doi:10.1126/science.aai9383