Background Globally, shifts in United States foreign aid policy have put HIV funding under duress. South Africa is unique in the region because its HIV programme is largely domestically funded, although donor funds and partnerships support key components. We estimated the epidemiological impact of ceased PEPFAR support for specific services and the costs and cost-effectiveness of the South African government (SAG) potentially taking over these services.

Methods We used a costed version of Thembisa, a South African HIV transmission model, to simulate four scenarios: a minimum scenario assuming intervention coverage reducing proportional to PEPFAR’s funding share of specific activities in 2023; a maximum scenario assuming additional health system impacts; and sub-scenarios either with 3-year recovery (2029-2031) or no recovery to previous coverage. HIV programme costs were estimated from the provider perspective (SAG) in 2024/25 US dollars.

Results Over 2025-2028, discontinuing PEPFAR funding in South Africa without replacement by SAG would result in 150,000-296,000 additional new HIV infections (29-56% increase) and 56,000-65,000 additional AIDS-related deaths (33-38%). Permanent discontinuation of currently PEPFAR-supported services over the next 20 years increases this to 1.1-2.1 million additional new HIV infections and 519,000-712,000 additional AIDS deaths. To sustain services, SAG needs to spend an additional $710 million to $1.5 billion between 2025 and 2028. Under a reduced budget, the most cost-effective interventions to preserve are ART and PrEP.

Conclusion Unmanaged PEPFAR exit from South Africa threatens to undo a decade of progress towards ending AIDS as a public health threat unless services are taken over by other funders, including SAG.

Work presented here was supported by a grant from the Gates Foundation (INV-063625, Project Linganisa). GMR and LJ received grants from USAID South Africa, BMGF, WHO and FIND.

a grant from the Gates Foundation (INV-063625, Project Linganisa).

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Sources of support: Work presented here was supported by a grant from the Gates Foundation (INV-063625, Project Linganisa).

1 This means a resulting 86% of baseline ART coverage (82%), i.e. 71% of PLHIV being covered.

2 This means a resulting 72% of baseline ART coverage, i.e. 60% of PLHIV being covered.

All data produced in the present study are available upon reasonable request to the authors.