BIOMEDICAL PREVENTION OF HIV IN WOMEN: CHALLENGES AND APPROACHES, WITH PARTICULAR REFERENCE TO THE VAGINAL MICROBIOME

Although great progress has been made in treating HIV-1 infection globally, incidence remains high in many locales, especially sub-Saharan Africa. Two-thirds of the burden of disease is there, and among those infected, 60% are women. Pre-exposure prophylaxis, the administration of a drug to prevent acquisition of infection, has proven to be a promising prevention modality for HIV-1 when administered as a daily oral regimen of tenofovir disoproxil fumarate/emtricitabine. However, data suggest that oral tenofovir disoproxil fumarate/emtricitabine may not achieve protective concentrations in the cervicovaginal tissue as rapidly as it does in the rectum. Moreover, a relative paucity of the beneficial vaginal bacteria Lactobacillus crispatus, along with a commensurate increase in the vaginal anaerobes that characterize bacterial vaginosis, strongly increases risk of HIV-1 acquisition and may even modify efficacy of topical tenofovir when used as pre-exposure prophylaxis. bacterial vaginosis, a globally prevalent infection that increases women's risk of HIV-1 acquisition, and presents serious other reproductive health risks and management challenges, presumably involves survival of treatment-resistant biofilm communities. Methods to effect sustained improvement in the vaginal microenvironment are urgently needed.