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Changes in hepatitis C virus genotype distribution in Japan
H Toyoda1, T Kumada1, K Takaguchi2
1Department of Gastroenterology,Ogaki Municipal Hospital,Ogaki,Japan.
Epidemiology and Infection
|March 7, 2014
Summary
Hepatitis C virus (HCV) genotype distribution in Japan has shifted significantly. The dominant genotype 1b decreased in younger populations, while genotype 2b increased, indicating evolving infection patterns.
Area of Science:
- Hepatology
- Virology
- Epidemiology
Background:
- Hepatitis C virus (HCV) infection is influenced by viral genotypes, impacting disease progression and treatment outcomes.
- HCV genotype 1b has historically been predominant in Japan.
- Effective HCV transmission prevention measures were implemented in Japan starting in 1990.
Purpose of the Study:
- To investigate the changes in HCV genotype distribution among Japanese individuals.
- To analyze the association between HCV genotype prevalence and birth cohorts.
Main Methods:
- A retrospective study analyzing 5515 Japanese individuals with HCV infection across three institutions in different regions.
- Genotype distribution was examined based on patient birth year.
Main Results:
- The proportion of HCV genotype 1b declined to less than 50% in individuals born after 1970.
- Conversely, the prevalence of HCV genotype 2b showed an increasing trend in birth cohorts from 1920-1929 onwards.
- These shifts in genotype distribution were consistent across different geographical areas in Japan.
Conclusions:
- HCV genotype distribution in Japan has undergone significant changes over time.
- The observed shifts, particularly the decrease in genotype 1b and increase in genotype 2b among younger cohorts, suggest evolving epidemiological patterns of HCV infection in Japan.
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