Early hepatitis B vaccination may be ineffective in teenagers

By Helen Albert, Senior medwireNews Reporter

Research reveals that many infants who receive the complete series of hepatitis B virus (HBV) vaccinations have lost their protection by the time they reach adolescence.

Li-Yu Wang (Mackay Medical College, New Taipei City, Taiwan) and colleagues found that by a mean age of 15.6 years, around 15% of those who received hepatitis B immunoglobulin (HBIG) after birth plus up to four doses of the hepatitis B vaccine tested positive for hepatitis B surface antigen (HBsAg), an early indicator of infection or carriage of HBV.

The team found that significantly more (15-29%) children who received HBIG off schedule and whose mothers were persistently positive for HBsAg were positive for HBsAg themselves.

"Chronic hepatitis B virus 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," commented Wang in a press statement.

"While infantile HBV vaccination is highly effective, it is not 100% and our study examines the long-term success of the HBV vaccine in a high-risk population."

Wang and team recruited 8733 Taiwanese high-school students born after July 1987 to take part in their study. All the students were tested for HBsAg and for antibodies to HBsAg (anti-HBs), the latter indicating prior vaccination or cleared HBV infection.

Overall, around 87% of the cohort had records showing receipt of three or more doses of the HBV vaccine before the age of 3 years. Additional receipt of HBIG was documented in 381 children.

Writing in Hepatology, the team reports that 1.9% of the overall cohort were HBsAg positive and 48.3% had anti-HBs. In children who received HBIG, the HBsAg positivity was 15%.

Receiving less than the four recommended doses of the HBV vaccine was also associated with an increased risk for HBsAg positivity, with those receiving three and one/two doses having a 1.52- and 2.85-fold increased risk compared with those who had four doses.

Wang and colleagues also note that of 1974 HBsAg-negative students who received a booster vaccination against HBV, those with anti-HBs titers of 1.0-9.9 mIU/mL prebooster achieved higher postbooster levels than those with prebooster anti-HBs titers below 1.0 mIU/mL.

"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," conclude the authors.

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