1701. Added Benefits of Pre-exposure Prophylaxis Use on HIV Incidence with Minimal Changes in Efficiency in the Context of High Treatment Engagement among Men Who Have Sex with Men
Authors: Singleton Alyson L , Marshall Brandon D , Zang Xiao , Nunn Amy S , Goedel William C 
Published: January 2021

Abstract

Background
Although there is ongoing debate over the need for substantial increases in PrEP use when antiretroviral treatment confers the dual benefits of reducing HIV-related morbidity and mortality and the risk of HIV transmission, no studies to date have quantified the potential added benefits of PrEP use in settings with high treatment engagement across variable sub-epidemics in the United States.

Methods
We used a previously published agent-based network model to simulate HIV transmission in a dynamic network of 17,440 Black/African American and White MSM in Atlanta, Georgia from 2015 to 2024 to understand how the magnitude of reductions in HIV incidence attributable to varying levels of PrEP use (0–90%) changes in potential futures where high levels of treatment engagement (i.e. the UNAIDS ‘90-90-90’ goals and eventual ‘95-95-95’ goals) are achieved and maintained, as compared to current levels of treatment engagement in Atlanta (Figure 1).
Model inputs related to HIV treatment engagement among Black/African American and White men who have sex with men in Atlanta. A comparison of current levels of treatment engagement (Panel A) to treatment engagement at ‘90-90-90’ (Panel B) and ‘95-95-95’ goals (Panel C).

Results
Even at achievement and maintenance of ‘90-90-90’ goals, 75% PrEP coverage reduced incidence rates by an additional 67.9% and 74.2% to 1.53 (SI: 1.39, 1.70) and 0.355 (SI: 0.316, 0.391) per 100 person-years for Black/African American and White MSM, respectively (Figure 2), compared to the same scenario with no PrEP use. Additionally, an increase from 15% PrEP coverage to 75% under ‘90-90-90’ goals only increased person-years of PrEP use per HIV infection averted, a measure of efficiency of PrEP, by 8.1% and 10.5% to 26.7 (SI: 25.6, 28.0) and 73.3 (SI: 70.6, 75.7) among Black/African American MSM and White MSM, respectively (Figure 3).

Overall (Panel A) and race-stratified (Panel B and Panel C) marginal changes in HIV incidence over ten years among Black/African American and White men who have sex with men in Atlanta across scenarios of varied levels of treatment engagement among agents living with HIV infection and levels of pre-exposure prophylaxis use among HIV-uninfected agents. Note: All changes are calculated within each set of treatment scenarios relative to a scenario where no agents use pre-exposure prophylaxis.

Person-years of pre-exposure prophylaxis use per HIV infection averted among Black/African American (Panel A) and White (Panel B) men who have sex with men in Atlanta across scenarios of varied levels of treatment engagement among agents living with HIV infection and levels of pre-exposure prophylaxis use among HIV-uninfected agents. Note: The number of HIV infections averted is calculated within each set of treatment scenarios relative to a scenario where no agents use pre-exposure prophylaxis.

Conclusion
Even in the context of high treatment engagement, substantial expansion of PrEP use still contributes to meaningful decreases in HIV incidence among MSM with minimal changes in person-years of PrEP use per HIV infection averted, particularly for Black/African American MSM.

Disclosures
All Authors: No reported disclosures