Assessing risk for HIV infection among adolescent girls in SouthAfrica: an evaluation of the VOICE risk score (HPTN 068)
AbstractIntroduction:To maximize impact and minimize costs, antiretroviral pre-exposure prophylaxis (PrEP) interventions should beoffered to those at highest risk for HIV infection. The risk score derived from the VOICE trial is one tool currently being uti-lized to determine eligibility in adolescent PrEP trials in sub-Saharan Africa. This study is aimed at evaluating the utility of therisk score in predicting HIV incidence among a cohort of adolescent girls in rural South Africa.Methods:We utilized data from HIV Prevention Trials Network (HPTN) 068, a phase III randomized controlled trial con-ducted in rural Mpumalanga province, South Africa. School-attending young women aged 13 to 20 years were enrolled intothe trial from 2011 to 2012 and followed for up to three years. A risk score based on individual-level risk factors measuredat enrolment was calculated for HPTN 068 participants who completed a one-year follow-up visit and were HIV seronegativeat enrolment. Possible scores ranged from 0 to 10. A proportional hazards model was then used to determine if risk score atenrolment was predictive of incident HIV infection at follow-up and an area under the curve analysis was used to examine thepredictive ability of the score.Results and Discussion:The risk score had limited variability in the HPTN 068 sample. Scores≥5 identified 85% of incidentinfections from 94% of the sample, compared to the VOICE sample in which scores≥5 identified 91% of incident infectionsfrom only 64% of participants. The risk score did not predict HIV incidence after one year of follow-up (hazardratio=1.029; 95% confidence interval (CI): 0.704, 1.503,p=.884) and showed poor predictive ability (area under thecurve=0.55; 95% CI: 0.44, 0.65). Certain individual risk factors that comprise the risk score may be context specific or notrelevant for adolescent populations. Additional factors should be considered when assessing risk for the purposes of deter-mining PrEP eligibility.Conclusions:The VOICE risk score demonstrated low utility to predict HIV incidence in the HPTN 068 sample. Findings high-light the need for an age and developmentally appropriate tool for assessing risk for HIV infection among adolescents. Use ofthe VOICE risk score for determining PrEP eligibility in younger populations should be carefully considered.