Hepatitis C virus transmission among people who inject drugs in the Middle East and North Africa: mathematical modeling analyses of incidence and intervention impact

Background The Middle East and North Africa (MENA) region is the most affected by hepatitis C virus (HCV) infection globally. This study aimed to estimate HCV incidence among people who inject drugs (PWID) in MENA and evaluate the impact of interventions. Methods A mathematical model was extended and applied to 13 countries with at least one data point on the population size of PWID and HCV antibody prevalence among PWID, generating estimates for the period 2024-2030. The model was calibrated using multiple datasets, primarily derived from systematic reviews and meta-analyses. Multivariable uncertainty analyses were conducted. Findings Incidence rate among PWID in the 13 countries combined was 10.4 per 100 person-years (95% UI: 8.0-14.1), with an estimated 42,364 new infections annually (95% UI: 27,990-57,540), accounting for 16.9% (95% UI: 8.3-28.2) of all cases in these countries. These fi gures varied widely across countries. A 75% reduction in needle/syringe sharing decreased viremic chronic infection prevalence by 14.2% (95% UI: 11.3-17.1), incidence rate by 33.8% (95% UI: 30.2-40.5), and annual new infections by 24.4% (95% UI: 17.7-30.1). A 10% reduction in PWID numbers and a 20% reduction in injection frequency decreased chronic infection prevalence by 1.7% (95% UI: 1.4-2.5), incidence rate by 4.2% (95% UI: 3.9-4.4), and annual new infections by 11.1% (95% UI: 10.9-11.9). Achieving 75% direct-acting antiviral treatment coverage by 2030 decreased chronic infection prevalence by 65.3% (95% UI: 64.8-65.8), incidence rate by 34.5% (95% UI: 29.6-40.3), and annual new infections by 25.3% (95% UI: 19.9-29.3). Combinations of interventions reduced these epidemiologic outcomes by up to 80%. Interpretation MENA experiences considerable HCV incidence among PWID. While the interventions showed potential, only large-scale or multi-intervention strategies can achieve meaningful reductions in HCV transmission.