Impact of an international HIV funding crisis on HIV infections and mortality in low-income and middle-income countries: a modelling study.

Background: International funding for HIV has been crucial in reducing new HIV transmissions and deaths. Five countries providing over 90% of international HIV funding have announced reductions in international aid of between 8% and 70% between 2025 and 2026, with the US Government pausing aid with immediate effect on Jan 20, 2025. We investigated the potential impact of these funding reductions on HIV incidence and mortality through mathematical modelling.

Methods: We used 26 country-validated Optima HIV models (Albania, Armenia, Azerbaijan, Belarus, Bhutan, Cambodia, Colombia, Costa Rica, Côte d'Ivoire, Dominican Republic, Eswatini, Georgia, Kazakhstan, Kenya, Kyrgyzstan, Malawi, Malaysia, Moldova, Mongolia, Mozambique, South Africa, Sri Lanka, Tajikistan, Uganda, Uzbekistan, and Zimbabwe). HIV incidence and mortality were projected across 2025-30 for a status quo scenario (most recent HIV spending continued) and four additional scenarios capturing the effects of anticipated international aid reductions for HIV prevention and testing, plus additional effects on treatment and facility-based testing resulting from immediate discontinuation of President's Emergency Fund for AIDS Relief (PEPFAR) support. Country-specific effects were estimated using sources of country-reported HIV funding. We disaggregated outcomes for children, adults in the general population, and adults in key populations. We extrapolated the scenario outcomes to all low-income and middle-income countries (LMICs) based on the modelled proportion of globally reported international aid by source (the 26 countries representing 49% of overall aid and 54% of PEPFAR aid). Upper and lower bounds reflected different mitigation and absorption assumptions.

Findings: Across all LMICs, an anticipated 24% weighted average of international aid reductions plus discontinued PEPFAR support could cause an additional 4·43-10·75 million new HIV infections and 0·77-2·93 million HIV-related deaths between 2025 and 2030 compared with the status quo. If PEPFAR support could be reinstated or equivalently recovered, this reduced to 0·07-1·73 million additional new HIV infections and 0·005-0·061 million HIV-related deaths. The effects were greatest in countries with a higher percentage of international funding and in those with increasing incidence of HIV among key populations.

Interpretation: Unmitigated funding reductions could significantly reverse progress in the HIV response by 2030, disproportionately affecting sub-Saharan African countries and key and vulnerable populations. Sustainable financing mechanisms are crucial to ensure people have continued access to HIV prevention, testing, and treatment programmes, thereby reducing new HIV infections and deaths.

Funding: None.