A vaginal ring (VR) containing dapivirine (DPV) is under evaluation for pre-exposure prophylaxis (PrEP) for HIV prevention among women. However, the potential impact and cost-effectiveness of DPV PrEP scale-up is unknown. Further, cross-resistance is common between DPV and first-line antiretroviral therapy (ART) in resource-limited settings.
We modeled the HIV epidemic in KwaZulu-Natal, South Africa and compared the combined scale-up of ART, male medical circumcision (MMC) and DPV VR PrEP to a baseline scenario of just ART and MMC. We simulated four strategies of PrEP scale-up among women during 2017–2027: unprioritized (to 15–54 year-olds) or age-prioritized (to 15–24 or 20–29 year-olds) reaching 15% overall population-level coverage; or prioritized to female sex workers (FSWs) (~0.1% overall coverage). We examined scenarios of low (50%) or high (95%) average adherence, assuming 90% PrEP efficacy against wild-type and drug-resistant HIV, and 80% cross-resistance between ART and PrEP, and modeled HIV drug resistance dynamics in genital and blood compartments. We examined health outcomes and drug resistance consequences relative to baseline and calculated cost-effectiveness ratios while discounting healthcare and intervention costs (PrEP costs: $95/person-year) and health outcomes by 3% annually.
At low (50%) adherence, unprioritized DPV VR PrEP scale-up prevented 8.8% of (undiscounted) new infections over ten years at $8,678 per infection prevented. Impact and costs improved modestly with scale-up among women aged 15–24 (9.4% infections prevented, $8,059 per infection prevented) but more substantially when focused to women aged 20–29 (14.1%, $5,052). Scale-up among FSWs prevented the fewest infections overall (4.6%; given their small group size), but at lower cost, reducing the cumulative total costs by $21.4 million. At high (95%) compared to low adherence, HIV prevention increased by 86%–106% and cost-effectiveness ratios decreased by 52%–57% (Table). PrEP scale-up decreased prevalent drug-resistant cases at 2027 by 1.6%–7.4% and 4.4%–14.8% in the low and high adherence scenarios respectively; however, these decreases diminished by relative 2%–12% when in addition to blood, resistance was also tracked in the genital compartment.
DPV VR PrEP could have considerable impact on HIV prevention at compelling economic value when prioritized to women by age and could decrease drug resistance, even if adherence is modest.