Insights from a national survey in 2021 and from modelling on progress towards hepatitis C virus elimination in the country of Georgia since 2015

Background Between May 2015 and February 2022, 77,168 hepatitis C virus (HCV)-infected people in Georgia have been treated through an HCV elimination programme. To project the programme’s long-term impacts, an HCV infection model was initially developed, based on data from surveys among people who inject drugs and a national serosurvey in 2015. Aim Accounting for follow-up surveys in 2021, we validate and update projections of HCV infection prevalence and incidence. Method We assessed the initial model projections’ accuracy for overall prevalence, by age, sex, and among people who ever injected drugs, compared with 2021 serosurvey data. We used 2021 results to weight model fits and to recalculate the national programme’s impact leading up to March 2022 on HCV infection incidence rates. Cases and deaths averted were estimated. The impact of reduced treatment rates during the COVID-19 pandemic was assessed. Results The original model overpredicted adult (≥ 18 years old) chronic HCV infection prevalence for 2021 (2.7%; 95% credible interval (CrI): 1.9–3.5%) compared with a 2021 serosurvey (1.8%; 95% confidence interval (CI): 1.3–2.4%). Weighted model projections estimated a 60% decrease in HCV infection incidence by March 2022, with an absolute incidence of 66 (95% CrI: 34–131) per 100,000 person-years (overall population). Between May 2015 and March 2022, 9,186 (95% CrI: 5,396–16,720) infections and 842 (95% CrI: 489–1,324) deaths were averted. The COVID-19 pandemic resulted in 13,344 (95% CrI: 13,236–13,437) fewer treatments and 438 (95% CrI: 223-744) fewer averted infections by March 2022. Conclusion Results support the programme’s high effectiveness. At current treatment rate (406/month), 90% reductions in prevalence and incidence in Georgia are achievable by 2030.