This study aimed to estimate the cost-effectiveness and returns on investments of HIV
prevention programs implemented during 2006-2010 and to identify the optimal allocation of
resources across combinations of programs for an effective HIV prevention response to
inform the prioritization of funding and health resources in Vietnam. This study aims to
establish evidence of the cost-effectiveness and identify optimal allocations of limited
resources for greatest epidemiological impacts. Costs of programs were ascertained through
a comprehensive review of published national reports on HIV costing and collection of
primary costing data from the original sources. Relationships between program spending
over time and program-targeted risk factors or other relevant end points were assessed and
incorporated into a mathematical epidemiological HIV model calibrated to reflect the
epidemic trends in Vietnam. The spending-outcome relationships and an epidemiological
model were used to compare observed conditions with counterfactual scenarios of reduced
or no programs to calculate the cost-effectiveness and estimate healthcare costs saved and
thus the return on investment. Model simulations of epidemic projections over many
combinations of possible resource allocations were used to identify optimal allocations for
reducing new infections over the next HIV budget period.