Hepatitis B virus infection is still one of the major health problems in Korea, because of its high prevalence and its deleterious sequellae to liver cirrhosis and hepatocellular carcinoma. However, little is known about incidence(force of
infection) of
the viral infection. Investigation on the natural history of the virus, such as age-dependency of occurrence, is thus necessary to establish the efficient measures of prevention and management. This study was done to estimate the incidence of
hepatitis
B virus infection, as well as to assess the prevalent age group of the infection through a stochastic analysis using mathematical models. Data on positivity of hepatitis B virus markers(HBsAg, anti-HBs, anti-HBc) were obtained from two different
population; a typical rural population in Kyunggi province(n=741) and a health insurance beneficiaries in the Seoul City(n=726). As results, force of infection by the virus was decreasing until the age group around 20, and afterwards remained
stationary. The annual incidence of the infection was 15 per 100 persons at birth, 5 per 100 persons at the age of 10, and about 3 per 100 persons after the age of 20. Proportion of antigen positivity among persons infected by the virus was also
decreasing with age increasing. These results suggest that new infection of hepatitis B virus mostly occurs early in the in Korea, resulting in subsequent high prevalence of the infection.
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