Background:
STD prevention programs can reduce the health and economic burden of STDs.

Objective:
To develop a tool for STD program personnel to estimate the economic benefits of their STD programs.

Method:
We developed a series of equations that can be applied to estimate the direct medical costs and indirect costs (lost productivity) averted by STD prevention programs in the US. Costs and probabilities for these equations were based primarily on published studies. We focused on the benefits of treating persons with primary and secondary (P&S) syphilis, gonorrhea, and chlamydia, and the benefits of HIV counseling and testing. These benefits included the sequelae costs averted by treatment of persons with STDs, the prevention of congenital syphilis in infants born to mothers treated for P&S syphilis while pregnant, the interruption of STD transmission in the population, the reduction in STD-attributable HIV infections (HIV infections that would not have occurred without the facilitative effects of STDs on HIV transmission and acquisition), HIV infections averted by HIV counseling and testing, and the corresponding reductions in lost productivity.

Result:
STIC (Sexually Transmitted Infection Costs) Figure, a spreadsheet-based program, was developed to facilitate the application of the equations of the costs saved by STD prevention. For example, treatment of 100 gonorrhea cases (50 male, 50 female) was estimated to save $21,665 in direct costs ($8,760 through prevention of sequelae in the persons treated and $12,905 through population-level benefits) and $18,164 in indirect costs.

Conclusion:
Although estimating the economic impact of STD prevention is an inexact exercise, the equations we developed (and incorporated into the STIC Figure spreadsheet) can provide a useful approximation.

Implications:
STIC Figure can be a practical tool for STD program personnel to generate evidence-based estimates of the economic impact of their program, using routinely- collected data.