Modeling the fallout: projecting the global impact of donor funding cuts on HIV prevention, treatment, and care.

Purpose of review: Recent U.S. funding cuts and subsequent terminations to global HIV programs threaten decades-long progress towards ending the HIV epidemic. In response to financial and programmatic uncertainty, mathematical models have projected dire consequences of current and future reductions in aid. This review examines modeling studies published from 20 January through 30 May 2025 and presents a comparative analysis of model estimates and synthesizes key findings.

Recent findings: Nine modeling studies examined U.S. and international donor funding reduction scenarios, ranging from a temporary pause to indefinite termination, with most analyses focused on sub-Saharan Africa and PEPFAR-supported programs. Time horizons varied from short-term projections (2025-2026) to long-term estimates spanning the next 20  years. Geographic coverage differed across studies, with some models focused on individual countries (e.g., South Africa) and others projecting outcomes across all low- and middle-income countries (LMICs). Based on consensus projections, global donor funding cuts - including those proposed by the Trump administration - could result in 10 million additional HIV infections, including 1 million among children, and 3 million additional deaths over the next 5  years.

Summary: Early modeling studies converge on a clear message, that even partial reductions in external HIV funding pose the risk of reversing decades of progress, with disproportionate effects in high-burden countries reliant on PEPFAR funding. However, estimates vary widely due to heterogenous model structures and varying assumptions regarding funding cuts and adaptability of programs. These models should be interpreted as directional tools to guide decision-making, offering policymakers a tool to assess funding scenarios and anticipate potential consequences. For national governments, the models underscore the urgent need for sustained investment in HIV mitigation programs.