Abstract
HIV/AIDS remains one of the leading public health challenges in African countries, where
treatment and prevention programs are heavily reliant on external donor support. Recent
fluctuations in international aid, including PEPFAR budget cuts and shifting donor priorities,
have raised concerns about the sustainability of ART coverage and long-term epidemic
control. Motivated by these uncertainties, this study investigates how funding withdrawal
influences HIV transmission dynamics and treatment outcomes. We justify this focus by
noting that existing models often assume constant or unlimited resources, thereby underestimating
the fragility of epidemic control under financial shocks. Methodologically, we
extend deterministic compartmental models to embed funding as a dynamic state variable
directly affecting ART initiation, adherence, and prevention coverage, while stochastic simulations
are employed to capture variability in treatment continuity and resource allocation.
Using parameter estimates informed by South African data, the results demonstrate that reductions
in donor support can substantially elevate the basic reproduction number R0, prolong
epidemic persistence, and lead to higher AIDS related mortality. Policy simulations
further reveal that strengthening domestic health financing and implementing adaptive prevention
strategies are critical to maintaining epidemic control in the face of declining donor
contributions. These findings provide actionable insights for policymakers by demonstrating
that integrating financial constraints into epidemic modelling is essential for designing
resilient and sustainable HIV/AIDS programs in resource limited countries. Furthermore,
the study highlights the urgent need for long-term financial planning and diversified funding
streams to ensure the stability of HIV/AIDS interventions in African counties.