Background: Documenting the characteristics associated with the sharing of needles and drug injection equipment among people who inject drugs has important implications for monitoring drug-related trends. Since the inception of needle exchange programs in the U.S. in 1988, previous reviews on sharing and injection risk behaviors have been restrictive in either scope, population, interest, and/or context (PICo).

Objective: To document and aggregate existing literature on reports of needle and/or drug injection equipment sharing behaviors, as well as other injection-related HIV/HCV risk behavior in the U.S. in the era of needle exchange programs (i.e.,1988 to 2019).

Methods: To be included in the review, eligible sources must have been published between January 1988 and December 2019, written in English, limited geographically to the United States, and included people aged 18 years or older. Eligible sources were collected from online databases and must have also reported one or more of the prespecified 10 data items and outcomes. Additionally, an online survey of syringe exchange programs participating in the North American Syringe Exchange Network (NASEN) was included.

Results: Of 9,925 identified sources, 2,486 were eligible for full review. Of these, n=354 unique research studies from 39 U.S. states were eligible for inclusion. For the 10 data items and outcomes, preliminary findings have tallied: 1) syringe sharing (n=289); 2) non-syringe drug injection equipment sharing (n=146); 3) syringe cleaning practices (n=84); 4) syringe-mediated drug sharing (n=69); 5) speedball and/or goofball injection (n=136); 6) sharing partner (n=35); 7) injection partner (n=41); 8) shooting gallery attendance (n=104); 9) HIV/HCV serosorting (n=8); and 10) syringe reuse (n=30). These findings represent 29.3% of the total data screening and extraction processes to be done.

Conclusions: Researchers, health-policy leaders, and health services providers may utilize this summarization of syringe sharing and other HIV/HCV injection risk behavior to enhance the understanding of injection-related behaviors with the goal of optimizing the provision of harm reduction services to persons who inject drugs.