Can needle and syringe programmes and opiate substitution therapy achieve substantial reductions in HCV prevalence? Model projections for different epidemic settings

Investigate impact of scaling-up opiate substitution therapy (OST) and high coverage needle and syringe programmes (100%NSP – obtaining more sterile syringes than you inject) on HCV prevalence amongst injecting drug users (IDUs).

HCV transmission modelling using UK estimates for effect of OST and 100%NSP on individual risk of HCV infection.

Range of chronic HCV prevalent (20/40/60%) settings with no OST/100%NSP, and UK setting with 50% coverage of both OST and 100%NSP.

Injecting drug users.

Decrease in HCV prevalence after 5-20 years due to scale-up of OST and 100%NSP to 20/40/60% coverage in no OST/100%NSP settings, or from 50% to 60/70/80% coverage in UK setting.

For 40% chronic HCV prevalence, scaling-up OST and 100%NSP from 0% to 20% coverage reduces HCV prevalence by 13% after 10 years. This increases to a 24/33% relative reduction at 40/60% coverage. Marginally less impact occurs in higher prevalence settings over 10 years, but this becomes more pronounced over time. In the UK, without current coverage levels of OST and 100%NSP the chronic HCV prevalence could be 65% instead of 40%. However, further increasing OST and 100%NSP coverage is unlikely to reduce chronic prevalence to less than 30% over ten years unless coverage becomes ≥80%.

Scaling-up opiate substitution therapy and need sharing programmes can reduce hepatitis C prevalence amongst injecting drug users, but reductions can be modest and require long-term sustained intervention coverage. In high coverage settings, other interventions are needed to further decrease hepatitis C prevalence. In low coverage settings, sustained scale-up of both interventions is needed.