Impact Evaluation of a Policy Intervention for HIV Prevention in Washington, DC.

Syringe exchange programs (SEPs) lower HIV risk. From 1998 to 2007, Congress prohibited Washington, DC, from using municipal revenue for SEPs. We examined the impact of policy change on IDU-associated HIV cases. We used surveillance data for new IDU-associated HIV cases between September 1996 and December 2011 to build an ARIMA model and forecasted the expected number of IDU-associated cases in the 24 months following policy change. Interrupted time series analyses (ITSA) were used to assess epidemic impact of policy change. There were 176 IDU-associated HIV cases in the 2 years post-policy change; our model predicted 296 IDU-associated HIV cases had the policy remained in place, yielding a difference of 120 averted HIV cases. ITSA identified significant immediate (B = -6.0355, p = .0005) and slope changes (B = -.1241, p = .0427) attributed to policy change. Policy change is an effective structural intervention for HIV prevention when it facilitates the implementation of services needed by vulnerable populations.