Needle syringe programmes and opioid substitution therapy for preventing hepatitis C transmission in people who inject drugs [Intervention review] (2017)

Review question: We examine research on the effect of needle syringe programmes (NSP) and opioid substitution treatment (OST) in reducing the risk of becoming infected with the hepatitis C virus.
Background: There are around 114.9 million people living with hepatitis C and 3 to 4 million people newly infected each year. The main risk for becoming infected is sharing used needles/syringes. Almost half the people who inject drugs have hepatitis C. The provision of sterile injecting equipment through NSPs reduces the need for sharing equipment when preparing and injecting drugs. OST is taken orally and reduces frequency of injection and unsafe injecting practices. We examined whether NSP and OST, provided alone or together, are effective in reducing the chances of becoming infected with hepatitis C in people who inject drugs.
Search date: The evidence is current to November 2015.
Study characteristics: We identified 28 research studies across Europe, Australia, North America and China. On average across the studies, the rate of new hepatitis C infections per year was 19.0 for every 100 people. Data from 11,070 people who inject drugs who were not infected with hepatitis C at the start of the study were combined in the analysis. Of the sample, 32% were female, 50% injected opioids, 51% injected daily, and 40% had been homeless. Our study was funded by the National Institute of Health Research's (NIHR) Public Health Research Programme, the Health Protection Research Unit in Evaluation of Interventions, and the European Commission Drug Prevention and Information Programme (DIPP), Treatment as Prevention in Europe: Model Projections.
Key results: Current use of OST (defined as use at the time of survey or within the previous six months) may reduce risk of acquiring hepatitis C by 50%. We are uncertain whether high coverage NSP (defined as regular attendance at an NSP or all injections being covered by a new needle/syringe) reduces the risk of becoming infected with hepatitis C across all studies globally, but there was some evidence from studies in Europe that high NSP coverage may reduce the risk of hepatitis C infection by 76%. The combined use of high coverage NSP with OST may reduce risk of hepatitis C infection by 74%.
Quality of the evidence: Quality of evidence ranged from moderate to very low because none of the studies used the gold standard design of randomised controlled trials.