Progress towards HCV elimination in the country of Georgia: insights from modelling and national survey

ABSTRACT

Background and aims: A national serosurvey in 2015 found the country of Georgia had high hepatitis C virus (HCV) prevalence, with 5.4% of adults (∼150, 000 people) chronically infected. In April 2015, Georgia launched a national program to eliminate HCV infection (reduce prevalence by 90%). We developed an HCV transmission model to capture current and historical dynamics of HCV infection in Georgia, and project long-term impact of the elimination program. A follow-up serosurvey in 2021 provided data which was used to validate the model and update impact projections. Method: The original model was calibrated to the 2015 serosurvey and surveys among people who inject drugs (PWID), accounting for age, sex, PWID status, and liver disease state. We compare model projected prevalence overall and by age group, sex, and among ever injected drugs to 2021 serosurvey prevalence, and filter the original 532 parameter sets to match the serosurvey results.We used logistic regression to assess which input parameters or model characteristics affect fit.We used program data on 77,168 persons treated May 2015- February 2022 to estimate current incidence of HCV infection, cases and deaths averted.We project the impact of reductions in treatment rates that occurred in during the COVID-19 epidemic. Results: The original modelled adult hepatitis C prevalence for 2021 (2.7%, 1.9–3.5%) was higher than the observed serosurvey prevalence (1.8%, 1.3–2.4%);across all groups uncertainty bounds overlap. Only 14% of 532 model runs fit within the 95% confidence interval of all hepatitis C prevalence estimates;32% fit overall, 28% fit in females, 43% fit in males, 85% fit in ever-injected drugs. Runs that fit the 2021 serosurvey data tend to have lower total population and lower general population hepatitis C incidence, suggesting the model overestimated the initial burden of infection. After filtering, modelled hepatitis C adult prevalence is slightly higher than the observed prevalence (2.1%, 1.6–2.4%). Hepatitis C incidence in March 2022 is estimated to be 0.05 (95% credible interval (CrI) 0.03–0.11) per 100 person-years in general population, and 1.14 (0.08–6.4) per 100 person-years in PWID, a 60% decrease since 2015. As of March 2022, 9, 186 (5, 396–16, 720) infections and 842 (489–1324) deaths have been averted, with benefit accumulating to 26, 154 (15, 850–47, 627) infections and 3, 971 (2, 516–5, 536) deaths averted if tracked to 2030. Treatment numbers went from 996/month in 2019 to 406/month March 2020-March 2022 during the COVID-19 pandemic, resulting in 14, 127 fewer treatments, 471 (242–817) fewer infections averted by March 2022. At 406 treatments/month, elimination can be reached in 2031.(Figure Presented)Conclusion: HCV prevalence reduction due to treatment and prevention interventions was greater than originally projected, but treatment numbers must still increase in order to reach HCV elimination by 2030