Treatment as Prevention and HIV Transmission in the US

Providing treatment to all people living with HIV (PLHIV), a strategy known as treatment as prevention, is a highly effective intervention against HIV. Policies that reduce access to antiretroviral therapy (ART), an important component of treatment-as-prevention (TasP) strategies, might undermine decades of HIV control in the US and result in thousands of new HIV infections.

To estimate the association between TasP and the HIV epidemic in the US from 2011 to 2025 and to project the outcomes of a potential rollback of this policy.

In this decision analytical model, HIV incidence and prevalence from 2011 to 2030 were simulated. PLHIV were stratified by transmission group (men who have sex with men, heterosexual men, heterosexual women, and people who inject drugs) and stage of the HIV care cascade (undiagnosed, diagnosed but not receiving ART, receiving ART with detectable viremia, and receiving ART and virally suppressed).

Change in HIV care cascade.

Annual HIV transmissions from 2011 to 2025 were compared with HIV care cascade (1) following the observed trend (with TasP) or (2) fixed at 2011 levels, without TasP. The impact of preexposure prophylaxis (PreP) rollout since 2017 was also estimated. Finally, HIV transmission from 2026 to 2030 was projected assuming that (1) 10% to 30% of PLHIV immediately lose ART access, reflecting the estimated share of ART funded through federal subsidies, (2) no change, or (3) a moderate increase in ART access.

In 2011, there were 1 008 300 PLHIV. In 2025, treatment as prevention was associated with an estimated 44.5% reduction in HIV incidence; PrEP, a 20.5% reduction; and treatment as prevention plus PrEP, a 61.8% reduction. From 2011 to 2025, TasP averted an estimated 197 400 new HIV acquisitions in the US, PrEP averted 33 200, and the 2 combined averted 293 200. Immediate losses of ART access affecting 10%, 20%, or 30% of treated PLHIV were associated with approximately 35 900, 81 700, and 111 200 additional HIV acquisitions between 2026 and 2030, respectively, substantially reversing the population-level gains achieved through TasP.

In this decision analytical model estimating the potential effects of reductions in ART access, findings suggest that these reductions will not only jeopardize individual health outcomes and over a decade of progress toward HIV elimination but also result in thousands of new HIV acquisitions over the next 5 years.