Can HIV epidemics among MSM be eliminated through participation in preexposure prophylaxis rollouts?

To study the conditions under which preexposure prophylaxis (PrEP) coverage can eliminate HIV among MSM in the Paris region.

Mathematical modeling.

We propose an innovative approach, combining a transmission model with a game-theoretic model, for decision-making about PrEP use. Individuals at high risk of HIV infection decide to use PrEP, depending on their perceived risk of infection and the relative cost of using PrEP versus antiretroviral treatment (ART), which includes monetary and/or nonmonetary aspects, such as price and access model of PrEP, consequences of being infected and lifelong ART.

If individuals assessed correctly their infection risk, and the cost of using PrEP were sufficiently low, then the PrEP rollout could lead to elimination. Specifically, assuming 86% PrEP effectiveness, as observed in two clinical trials, a minimum PrEP coverage of 55% [95% confidence interval (CI) 43-64%] among high-risk MSM would achieve elimination in the Paris region. A complete condom drop by MSM using PrEP slightly increases the minimum PrEP coverage required for elimination, by ∼1%, whereas underestimation of their own HIV infection risk would require PrEP programs reduce the cost of using PrEP by a factor ∼2 to achieve elimination.

Elimination conditions are not yet met in the Paris region, where at most 47% of high-risk MSM were using PrEP as of mid-2019. Further lowering the cost of PrEP and promoting a fair perception of HIV risk are required and should be maintained in the long-run, to maintain elimination status.