Systematic Review of Reviews finds that Opiate Substitution Programs and Needle and Syringe Programs can Reduce Injection Risk Behaviour, However a Stronger Evidence Base for Interventions is needed to Prevent HIV and HCV Infection in People Who Inject Drugs.
It is estimated that worldwide approximately 3 million people who inject drugs (PWID) may be living with HIV and 10 million may have HCV. Preventing initial infection of HIV and HCV is therefore critical to reduce long-term morbidity amongst people who inject drugs.
Authors categorized/rated reviews according to a set of criterion in order to assess the quality of the evidence.
Needle Syringe Programs (NSP)
Thirty-nine of 43 studies found a reduction of injection risk behavior (IBR) associated with needle syringe programs (NSP). However, the effectiveness of NSP programs in the prevention of HIV was tentative and evidence for the prevention of HCV was considered insufficient by the authors.
Opiate Replacement Therapy (OSP)
Thirteen studies assessed prevalence of injecting drug use before and after OST and all found a decrease in injection risk behavior (IRB)
Drug Preparation Equipment
One study addressed the effect of provision of drug preparation equipment on HCV. This study found a positive impact, however was not considered sufficient evidence to support nor negate to show effectiveness.
Provision of Foils
No reviews were found on the provisions of foil to stimulate route transition, however this is not surprising given the recent introduction of this intervention. Primary studies may not yet be published.
Information, Education and Counseling (IEC) and Outreach
Five out of six core reviews found tentative of conclusive evidence in support of effectiveness of IEC in reducing IRB.
Supervised Injection Facilities
Authors concluded that there is tentative review level evidence to support the effectiveness of SIFs in reducing IRB and improving injecting hygiene.
– Interestingly, evidence for the effectiveness of NSP (needle syringe provision) and OST (opiate substitution treatment) was strongest in relation to IRB and HIV, yet the authors found little review-level evidence to support the impact of NSP and OST on HCV transmission.
Possible reasons for lack of evidence for HCV interventions
o A lack of recent reviews.
o Reductions observed in IRB studies may not be sufficient to reduce risk of incidence in HCV infection since HCV has greater transmissibility via syringe sharing or needle-stick injury compared to HIV.
o Very low levels of sharing, such as a few times per month, may be required to have an impact on HCV transmission between people who inject drugs.
– Interventions need to target both recent and longer-term injectors to have an impact of HCV incidence.
– A recent meta-analysis found a synergistic impact of NSP and OST in relation to HCV incidence. Those receiving OST and at least one sterile needle from NSP per injection had a 79% reduction in risk of HCV seroconversion as compared to those not receiving OST and with less than one sterile needle per injection. In addition, a cohort study found greater benefit of participation in NSP and OST compared to NSP or OST alone in relation to both HCV and HIV transmission.
– Combinations of harm reduction interventions provided with sufficient coverage is needed to impact on HCV and HIV transmission. Globally, only 6-12% of people who inject drugs (PWID) receive OST and only 1 to 4 needles are distributed per PWID per month.
– Identification of insufficient review level evidence relating to particular interventions does not infer a lack of effectiveness but rather a gap in the evidence base, inappropriate study designs, findings that have yet to be published, variability in prevalence and incidence of HIV or HCV and the inclusion of high risk populations.
Although interventions such as OST, NSO, or IEC can be effective in reducing HIV or HCV transmission and IRB, the evidence base regarding the impact of the range of harm reduction interventions on HIV and HCV transmission remains limited. Emerging evidence suggests that interventions need to be provided at high coverage and in combination to minimize risk of HCV and HIV infection amongst people who inject drugs.
MacArthur, G.J., Velzen, E., Palmateer, N. et al. (2014). Interventions to prevent HIV and Hepatitis C in People who inject drugs: A review of reviews to assess evidence of effectiveness. International Journal of Drug Policy. Vol, 25. Pp. 34-52.