Reduction in needle sharing among seattle-area injection drug users across 4 surveys, 1994-2013

Objectives.Weevaluated time trends in sharing needles and other injection equipment from 1994 to 2013 among injection drug users in the Seattle, Washington area. Methods. We combined data from 4 sources: the Risk Activity Variables, Epidemiology, and Network (RAVEN) study, recruited from institutional settings; the Kiwi study, recruited from jails; National HIV Behavioral Surveillance system (NHBS) surveys, which used respondent-driven sampling; and surveys at needle-exchange sites. Results. Levels of needle sharing were higher in the earlier studies: RAVEN, 1994 to 1997 (43%) and Kiwi, 1998 to 2002 (61%). In the NHBS surveys, the initial level of 44% in 2005 declined to 31% in the period 2009 to 2012. Across needle-exchange surveys (2009-2013) the level was 21%. There was a parallel reduction in sharing other injection equipment.These trends persisted after control for sociodemographic and risk-associated variables. There was a contemporaneous increase in the number of needles distributed by local needle exchanges and a decline in the number of reported HIV cases among injection drug users. Conclusions. The apparent long-term reduction in sharing injection equipment suggests substantial success in public health efforts to reduce the sharing of injection equipment.