A 20-year follow-up study revealed a dramatic drop in liver cancer cases among 6- to 19-year-olds who were vaccinated for the hepatitis B virus at birth, according to a study published online September 16 in the /i>Journal of the National Cancer Institute.

In July 1984, a universal vaccination program was initiated among newborn children in Taiwan to prevent the hepatitis B virus infection, which can predispose to the development of hepatocellular carcinoma, a primary malignancy of the liver.

For this study, Mei-Hwei Chang, M.D., of the Department of Pediatrics, National Taiwan University Hospital in Taipei, and colleagues collected data from almost 2,000 patients with hepatocellular carcinoma who were aged 6-29 years at diagnosis in Taiwan between 1983 and 2004. Age- and sex-specific incidence were compared among vaccinated and unvaccinated birth cohorts with regression models.

Sixty-four cases of hepatocellular carcinoma were found among people vaccinated in almost 38 million person-years vs. 444 cancers among unvaccinated people in almost 80 million person-years.

A few individuals have developed liver cancer despite the program. Analysis of their records shows that most of these patients, however, were not given enough doses of the vaccine, or were insufficiently protected when they were born to hepatitis B-infected mothers, according to the study.

"These data suggest that the effectiveness of the universal HBV immunization program to prevent hepatocellular carcinoma has extended beyond childhood and into young adulthood over the past two decades," the authors write.