We sought to examine the health impact and cost of PrEP implementation if implemented throughout the adult population of New York City (NYC) and compare it to strategies of prioritization to all men who have sex with men (MSM) or only those MSM who are at highest risk of HIV acquisition (HR MSM).
Method:
Using a previously developed deterministic, compartmental mathematical model of HIV progression and transmission we considered three scenarios for PrEP implementation: 1) PrEP for all HIV negative adults 2) PrEP for all HIV negative MSM 3) PrEP for high risk HIV negative MSM where high risk refers to those persons who are in multiple, concurrent partnerships or use injection drugs. Time horizon considered was twenty years. Model parameters were based on literature estimates. The risk reduction of PrEP on HIV acquisition was based on that experienced in published clinical trials with plausible bounds considered in sensitivity analysis. Wide ranges of uptake of the intervention and its cost were considered. Health benefits were measured as number and percentage of infections averted compared to a base case scenario without any PrEP. Cost-per-infection averted ratios were determined for the implementation scenarios considered.
Result:
Without additional HIV prevention interventions including expanded PrEP utilization the simulation predicted 58,024 new infections over 20 years in NYC. Population based PrEP would avert more than 19,000 (33%) new infections and 7,000 (45%) HIV related deaths over twenty years. The cost per infection averted is estimated at more than $54 million. Prioritization of PrEP to MSM or HR MSM retained 66% and 50% of the effect of population wide implementation, respectively. Prioritization to MSM or HR MSM was estimated to cost 2% and 1% of the total cost of population based PrEP. Under a set of optimistic assumptions (PrEP 50% of initial estimated cost, uptake greater than or equal to 70%) , PrEP prioritized to HR MSM may be cost-saving (cost-per-infection averted <$360,000).
Conclusion:
Wide scale PrEP implementation could have a significant impact on the HIV epidemic in NYC but its cost may be prohibitive. Use of PrEP in a more constrained and targeted approach, such a prioritization to MSM who are at high risk of HIV acquisition, could retain much of the impact at fractions of the cost.
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