Transactional Sex and HIV Incidence in a Cohort of Young Women in the Stepping Stones Trial

Abstract

Background: Structural drivers of the HIV epidemic are increasingly recognised, and cross-sectional research has shown an association between transactional sex and HIV prevalence, but evidence on the impact of transactional sex on HIV incidence in young women remains limited. Methods:We tested hypotheses that transactional sex predicted incident HIV infections in a dataset of 1077 HIV negative women aged 15-26 enrolled in a cluster randomised controlled trial.Incidence rate ratios were derived from multivariable Poisson models which included terms for age, HSV2, relationship power, condom use, intimate partner violence (IPV) exposure, treatment, stratum and person years of exposure to HIV.Results: 127 sexually active women acquired HIV during the study.HIV incidence was greater among women having transactional sex with a once off partner (IRR 3.29 95% CI 1.02, 10.55, p=0.046) and those having transactional sex with an on-going, concurrent partner (IRR 2.05 95% CI 1.20, 3.52, p=0.009).An analysis was performed to distinguish between the effects of a transactional sexual encounter or relationship and having a higher number of sexual partners or older partners, which are usually entailed in transactional sex.Women having transactional sex with a casual partner (on-going or once off) and two or more partners during follow up had an elevated risk of HIV acquisition (IRR 2.23 95% CI 1.28, 3.88, p=0.005),where as those just having two or more partners did not (IRR 1.20 95% CI 0.81, 1.77, p=0.368).Women with partners 5 or more years older did not have an elevated risk of HIV. Conclusions:Transactional sex with an on-going or once off partner elevates young women's risk of HIV infection.This finding is independent of partner number or age.These findings support the need for structural interventions in HIV prevention, with a stronger focus on reducing transactional sex.