Background
In Vietnam, including Haiphong, many hepatitis C virus (HCV) infections occur among people who inject drugs (PWID). In 2016, there were an estimated 10,000 people with a history of injecting drug use (IDU) in Haiphong. Multiple respondent-driven sampling (RDS) surveys tested for HCV among PWID in Haiphong, and a survey intervention (ANRS 12380 DRIVE-C) provided HCV testing and treatment; treating 979 current and former injectors in 2019. HCV testing and linkage-to-treatment in centres providing opiate agonist treatment (OAT) or antiretroviral therapy (ART) was provided in 2021/22 (831 treated), but no other HCV treatment has been available. We aimed to model the impact and cost-effectiveness of providing HCV testing and treatment to PWID through RDS surveys and/or OAT and ART centres in Haiphong.
Methods
A model of HCV transmission among PWID was calibrated in a Bayesian framework using data from Haiphong, mainly RDS surveys. The model included current and former injectors. A status quo (SQ) scenario modelled historical interventions, with no future HCV treatment. Future scenarios modelled the additional impact of providing from 2025-2030 HCV-testing and linkage-to-treatment in OAT and ART centres, and/or HCV testing and treatment in annual survey interventions of 1400 people with history of IDU, like DRIVE-C. We estimated the incremental cost-effectiveness ratio (ICER) per disability adjusted life-year (DALY) averted for the future scenarios compared to SQ over a 30-year time horizon (2025-2054; 3% annual discount rate).
Results
In the SQ, HCV incidence among injectors decreased from 7.0 (95% credibility interval 2.8-13.7) per 100 person-years (/100pyrs) in 2016, fitting well against validation data, to 4.6/100pyrs (1.6-9.1) in 2023 and 4.5/100pyrs (1.6-9.0) in 2030. For the future scenario with RDS surveys and HCV-testing and linkage-to-treatment in OAT and ART centres, HCV incidence decreases to 2.1/100pyrs (0.6-4.7) by 2030, or 2.8/100pyrs (0.9-5.7) with just annual RDS surveys. The mean ICER was €658/DALY averted for the scenario with HCV testing and treatment in both annual RDS surveys and in OAT and ART centres, whilst it was €762/DALY for annual RDS surveys with HCV testing and treatment; both cost-effective at a willingness-to-pay threshold of €2,334/DALY averted (50% of Vietnam’s 2023 GDP per capita).
Conclusions
Using RDS surveys and/or other care settings to scale-up HCV-testing and treatment are cost-effective strategies to reduce HCV incidence among PWID in Vietnam.