Some teens vulnerable to hepatitis B despite infant vaccination

A significant number of adolescents lose their protection from hepatitis B virus infection despite receiving a complete vaccination series as infants, according to a recent study conducted in Taiwan.

The research, which was published in January's issue of Hepatology, suggests that teens with high-risk mothers and teens whose immune system fails to remember prior viral exposure can lead to HBV reinfection. Mother-to-child transmission from mothers who carry the hepatitis B surface antigen is the cause of many HBV cases in Taiwan, MedicalXpress reports.

"Chronic HBV is a major health burden that leads to cirrhosis, liver cancer (hepatocellular carcinoma) and liver failure, shortening lives and placing a huge economic drain on society," Li-Yu Wang, the study's lead author, said, according to MedicalXpress. "While infantile HBV vaccination is highly effective, it is not 100 percent and our study examines the long-term success of the HBV vaccine in a high-risk population."

Taiwan began the world's first universal vaccination program for HBV in 1984, vaccinating newborns of infected mothers and expanding to all newborns in 1986. The study looked at 8,733 high school students born between July 1987 and July 1991. Antibodies to HBsAg were found in 48 percent of participants while two percent possessed the HBsAg. Of the students who received the vaccine as infants, 15 percent were positive for HBsAg.

Previous research found that the vaccine program reduced HBV infection and carrier rates of children in Taiwan. The studies also noted a decline in severe hepatitis in infants and liver cancer in children after the vaccine program began.

"Certainly the HBV vaccine program was a great success in Taiwan," Wang said, according to MedicalXpress. "For adolescents who lose protection, a HBV vaccination booster at age 15 or older should be considered, particularly in those born to HBsAg positive mothers or who had a high-risk of HBV exposure. Those born to high-risk mothers should first be screened for HBsAg."

The researchers suggested that routine anti-HBV treatment during pregnancy could help to reduce infant exposure to the virus. They noted that the efficacy and safety of the therapy plan must be proved prior to implementation, MedicalXpress reports.