The 131st Annual Meeting (November 15-19, 2003) of APHA

Abstract #71043

Steven D. Pinkerton, PhD, Center for AIDS Intervention Research, Medical Collge of Wisconsin, 2071 N Summit Ave, Milwaukee, WI 53202, 4144567700, Pinkrton@mcw.edu

Mathematical models of HIV transmission can be used to estimate the number of HIV infections that would be expected with and without a particular HIV prevention intervention. The difference between these estimates, which is the number of infected averted by the intervention, is an important measure of overall intervention effectiveness and a critical determinant of the cost-effectiveness of the intervention. Preventing people from becoming infected saves society money by averting future HIV-related medical care costs. However, these savings are realized only if intervention participants do not subsequently become infected through continuing risk behavior. Therefore, it is important that these models take into account the future risk behaviors of intervention participants to avoid counting "delayed" infections as "averted" infections. Here we present an expanded mathematical framework for assessing the impact of future risk behaviors on model-based assessments of intervention effectiveness. We consider both "primary" infections (i.e., infections among previously uninfected intervention participants) and "secondary" infections (i.e., infections among the partners of already infected intervention participants). Importantly, we examine how the issue of delayed infections affects the estimated cost-effectiveness, rather than just the effectiveness, of HIV prevention interventions.

Learning Objectives:

At the conclusion of the session, participants will
• understand the role of mathematical models in effectiveness and cost-effectiveness analyses of HIV prevention interventions
• appreciate the distinction between infections that are completely prevented by an intervention and those that are merely delayed
• understand the importance of delaying as well as preventing infections

Presenting author's disclosure statement:
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.