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Evaluating the Effectiveness of Baltimore's Needle Exchange Program

Ravi Varadhan, Department of Biostatistics, Johns Hopkins University

A needle exchange program (NEP) is a strategy for reducing the spread of HIV among injection drug users (IDU) by providing them clean needles in exchange for used ones. This not only reduces needle sharing, but also provides an opportunity to educate IDUs on avoiding risky behavior that may increase their chances of HIV infection. However, there are some arguments that NEP actually encourages drug use. In this presentation, we undertake an evaluation of the effectiveness of Baltimore's NEP using two different
statistical approaches: a traditional approach based on regression models comparing the HIV incidence among exchangers and non-exchangers, adjusting for background covariates, and an approach based on the framework of "principal stratification." The results from these two methods for the Baltimore NEP data will be presented. 


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