Epidemiology

Universal HBV vaccination protects Asian children from liver cancer

Last Updated: 2009-09-16 16:21:02 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Completing the recommended vaccination regimen (3 or 4 doses) against hepatitis B virus (HBV) during early childhood confers protection against the virus lasting at least into early adulthood, according to the Taiwan Hepatoma Study.

HBV infection is a major cause of hepatocellular carcinoma. The incidence of hepatocellular carcinoma in Taiwanese children was considerably reduced, but not eliminated, since the inception of a universal HBV immunization program in 1984. However, the duration of protection is not known.

Lead author Dr. Mei-Hwei Chang, from the National Taiwan University Hospital in Taipei, and colleagues used national registries to collect data on patients with hepatocellular carcinoma who were 6 to 29 years of age when they were diagnosed between 1983 and 2004. Incidence was compared among vaccinated and unvaccinated birth cohorts and published online September 16 in the Journal of the National Cancer Institute.

Among individuals who weren't vaccinated, 1894 cases of hepatocellular carcinoma were diagnosed. These included 74 patients, 6 to 9 years of age (incidence 0.49 per 100,000 person-years). The authors note that progressively greater numbers of older individuals were diagnosed, including 979 patients age 25-29 years (2.28 per 100,000 person-years). The age trend of increase in hepatocellular carcinoma incidence rates was highly significant in those aged 20 and over, (p < 0.001 for trend), but not for younger subjects.

By contrast, the hepatocellular carcinoma incidence rates ranged from 0.15 to 0.19 per 100,000 person-years for vaccinated patients up to 19 years old.

The risk of developing hepatocellular carcinoma in vaccinated children was significantly associated with receiving fewer than three doses of HPV vaccine (odds ratio = 4.32, compared with fully vaccinated youngsters). It was also associated with prenatal maternal seropositivity for the hepatitis B surface antigen (HBsAg, OR = 29.5) and the prenatal maternal hepatitis e antigen (OR 5.13 - 9.43, depending on whether hepatitis B immunoglobulin was given at birth).

"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," Dr. Chang's team concludes.

They add: "Because we observed a trend of increased hepatocellular carcinoma incidence among subjects who were aged 20 years or older in this study, we anticipate that continued work will be necessary to further establish the efficacy of the vaccine in preventing hepatocellular carcinoma among adults."

J Natl Cancer Inst 2009.