HEPATITIS-B VACCINATION AND HEPATOCELLULAR-CARCINOMA IN TAIWAN

Objective. In 1984, Taiwan started a large-scale hepatitis B vaccinati on program, enabling us to test the hypothesis that prevention of hepa titis B virus infection eventually decreases the incidence of hepatoce llular carcinoma. Methods. Groups aged 0 to 9 years and 10 to 100 year s in each calendar year were defined as the study group and the refere nce group, respectively. The percentage of children vaccinated in the study group increased during recent years. The study group and the ref erence group were divided into 5-year age strata (0 to 4, 5 to 9,..., 80 to 84, and 85 and over). Poisson regression was used to estimate ag e- and gender-adjusted liver carcinoma mortality rate ratios for 1974 through 1993, relative to 1974. Results. The adjusted mortality rate r atios of liver carcinoma in the study group decreased significantly fo r 1992 and 1993, whereas in the reference group it did not show the sa me result. A significantly declining trend of liver carcinoma mortalit y rate ratios was observed in the study group after 1984, whereas the same trend was not found in the reference group. Conclusions. Our resu lts support the hypothesis that hepatitis B vaccination can decrease t he incidence of hepatocellular carcinoma.