Hepatitis C Virus Subtypes Novel 6g-Related Subtype and 6w Could Be Indigenous in Southern Taiwan with Characteristic Geographic Distribution

Genetic history of hepatitis C virus genotype 6 in Taiwan

Unlike hepatitis C virus (HCV) genotype (GT) 6, which is widely circulated in Southeast Asia and South China, GT 6 was not reported in Taiwan until 2006. GT 1b and 2a, also known as global HCV subtypes, have been reported as major GTs circulating in Taiwan. Because of improvement in genotyping kits and sequencing techniques for the subtyping of HCV, an increasing number of GT 6 subtypes have been reported, especially subtype 6a among intravenous drug users with human immunodeficiency virus infection after an outbreak since 2003. Thus, HCV GT 6 infection is regarded to be closely associated with injection drug use. However, recently, we found an unexpectedly high GT 6 prevalence in the general population in Tainan, southern Taiwan. Most of these GT 6 samples belonged to a putative novel subtype closely related to 6g and 6w instead of 6a. Phylogenetic analyses indicated that this putative 6g-related novel subtype and 6w could be indigenous in southern Taiwan for centuries. Southern Taiwan could be the origin of HCV subtype 6w. This finding might change the perspective of HCV epidemiology in Taiwan.

Policy and Strategy for Hepatitis C Virus Elimination at the National Level: Experience in Taiwan

The estimated prevalence of anti-HCV was 3.1% in Taiwan. Studies have shown iatrogenic behavior was the major transmission route. It is highest in specific populations including patients with end stage renal disease (ESRD), human immunodeficiency virus infection, who inject drug (PWID), and under opioid substitution treatment. Approximately 405,160 patients were seropositive for HCV RNA and in need of treatment. Taiwan government claims to reach WHO's 2030 goal of HCV elimination by 2025 and works hard to resolve several barriers of HCV elimination including political commitment, sustainable financing, minimize reimbursement restrictions, instituted monitoring, and perform micro-elimination of specific populations. The last stage of HCV elimination is to accelerate the universal HCV screening program of populations aged 45-79 years and resolve the unawareness issue of HCV infection. Hopefully, we can achieve the targets of HCV elimination set by WHO and reach the goal earlier in 2025.