HIV Pre-Exposure Prophylaxis for Men Who Have Sex with Men in Taiwan: A Mathematical Modeling Study

Background: Men who have sex with men (MSM) are disproportionally affected by the HIV epidemic. There are now around 2,000 new MSM-HIV cases annually in Taiwan, under current HIV testing rate and antiretroviral therapy (ART) coverage. More effective strategy is urgently required to control the HIV epidemic in this vulnerable population. Both PROUD (2015) and IPERGAY (2015) studies demonstrated an 86% efficacy of PrEP, twice better than the 44% efficacy reported by the earlier iPrEX (2010) study. Therefore, previous modeling studies, which were based on iPrEX data, might under-estimated the actual impact of scaling-up PrEP among MSM. We aimed to evaluate the impact and cost-effectiveness of scaling-up PrEP on the MSM-HIV epidemic in Taiwan. Methods: We used the newest HIV surveillance and follow-up data to calibrate our HIV dynamic transmission model for MSM in Taiwan. We simulated the impact of scaling-up PrEP, Test-and-Treat, or both, on the future trajectory of HIV epidemic in MSM. We evaluate whether scaling-up PrEP will eliminate the MSM-HIV epidemic (incidence lower than 1/1000 per year, World Health Organization) in Taiwan, and whether such intervention is cost-effective. Findings: Scaling-up PrEP to 50% coverage or more will eliminate HIV among MSM by 2025. Annual HIV testing followed by immediate ART after HIV diagnosis in 90% of new cases will eliminate HIV epidemic by 2022. PrEP and Test-and-Treat are synergistic: if we target 15- to 44-year-old high-risk group, then 25% PrEP coverage in this group is sufficient to eliminate HIV epidemic by 2030 under biannual HIV testing followed by immediate ART in 75% of new cases. Cost analysis shows that NT$11.2 medical costs can be saved for every NT$1 spent on PrEP. Sensitivity analyses showed that efficacy of PrEP drug is the key factor for its role in HIV elimination, while method of administration (event-driven) and prioritization (high-risk group) are the key factors for its cost-effectiveness. Interpretation: PrEP is a highly effective HIV prevention strategy, and is cost-saving. Our results support the simultaneous expansion of both PrEP and HIV “Test-and-Treat” in Taiwan, with the aim to eliminate HIV epidemic among MSM in the next 10 years.