"After reviewing all of the research to date, the senior scientists of the Department and I have unanimously agreed that there is conclusive scientific evidence that syringe exchange programs, as part of a comprehensive HIV prevention strategy, are an effective public health intervention that reduces the transmission of HIV and does not encourage the use of illegal drugs."

Source

US Surgeon General Dr. David Satcher, Department of Health and Human Services, "Evidence-Based Findings on the Efficacy of Syringe Exchange Programs: An Analysis from the Assistant Secretary for Health and Surgeon General of the Scientific Research Completed Since April 1998" (Washington, DC: Dept. of Health and Human Services, 2000), p. 11.