Vaginal conditions may contribute more to HIV epidemic than previously thought

Various vaginal conditions, including bacterial vaginosis (BV) and yeast infection, have been linked to HIV acquisition. On June 1^st, an international team of researchers reported findings in the Journal of Acquired Immune Deficiency Syndrome, which indicate that women with current BV and candida are particularly likely to acquire HIV compared with others in the cohort.

Evidence of the role of BV and yeasts in increasing risk of HIV acquisition is limited to a few prospective studies but is mounting, while the effects of traditional practices such as vaginal cleansing and drying/tightening, and of vaginal mucosal inflammation are not well understood.

Janneke van de Wijgert and colleagues developed a multicentre, prospective cohort study, which enrolled 4531 HIV-negative women aged 18-35 years at family planning clinics in Zimbabwe and Uganda. Participants were tested for HIV, sexually transmitted infections (STIs) and vaginal conditions, and interviewed about vaginal practices every 3 months for between 15 and 24 months.

Standard microscopy practices were used to detect BV, yeasts, and to count white blood cells as a marker of inflammation. All participants were treated for STIs and vaginal infections, offered free contraception and condoms, and advice on risk reduction. This is the first study to examine the relationships between different vaginal conditions and to measure a marker of vaginal inflammation.

In Uganda, 96% of women completed 24 months follow-up, while in Zimbabwe, 88% completed the study to 24 months. Over the study, HIV incidence was 4.12 and 1.53 per 100 woman-years of follow-up in Zimbabwe and Uganda, respectively (213 new infections). In a multivariate model, which included other pre-specified risk factors and confounders, women with BV or vaginal yeast were more likely to acquire HIV, especially if the condition was present at the same visit as the new HIV infection and at the visit preceding it (hazard ratio [HR] = 1.67, p

The likelihood of acquiring HIV was higher if the infections were noted at the same and previous visit to that when the HIV infection was detected. However, these relationships did not seem to be mediated by mucosal inflammation. Vaginal cleansing or other practices also were not associated with HIV acquisition in the multivariate model. These practices were reported by small proportions of women. However, such practices have been previously linked with an increase in BV.

Given the high prevalence of BV and yeast in many countries with generalised HIV epidemics, “a modest increase in the relative risk of HIV transmission could lead to a substantial attributable risk of HIV infection”, the team reports. Interventions aimed at controlling BV and yeast pose challenges in resource-poor settings but “could be an important HIV prevention strategy, particularly in sub-Saharan Africa, where most HIV infections among women occur,” the authors conclude.