Viral hepatitis B is a leading cause of acute and chronic liver disease worldwide. The World Health Organization (WHO) estimates that, globally, about 2 billion people have been infected with hepatitis B virus (HBV). More than 350 million people are chronically infected. WHO recommends that all countries should have universal infant or adolescent hepatitis B vaccination integrated into their national immunisation programmes by 1997. By the end of 2004, 168 countries implemented these immunisation programmes. However, whether vaccinated infants maintain protection or need a booster vaccination to sustain immunity has not been clear.
Alessandro Remo Zanetti (Institute of Virology Faculty of Medicine, Milan, Italy) and colleagues looked at whether concentrations of antibodies against hepatitis B were retained in 1212 children and 446 Italian Air Force recruits vaccinated as infants and adolescents respectively. They found that 64% of children and 89% of the recruits retained protective concentrations of antibodies. The study shows that infant and adolescent immune systems can recall responding to hepatitis B more than 10 years after immunisation.
Professor Zanetti concludes: "In light of our findings, the use of routine booster doses of hepatitis B vaccine does not seem necessary to maintain long-term protection in immunocompetent individuals vaccinated as infants and teenagers."
In an accompanying comment Ding-Shinn Chen (National Taiwan University, Taiwan) states: "Unless accumulating data show a significant increase of HBV infection in adolescents or adults who were vaccinated as children, a policy of booster vaccination in a population should not be recommended. We believe that this applies both to hyperendemic and lowly-endemic areas of the world."
Contact: Professor Alessandro R Zanetti, Institute of Virology Faculty of Medicine, University of Milan, Via C. Pascal 38, Italy. T) +39 02 503 15126 alessandro.zanetti@unimi.it
Comment: Professor Ding-Shinn Chen, National Taiwan University, College of Medicine, 1 Chang-Te Street, Taipei 100, Taiwan. T) +886 2 2312 3456x7120 dschen@ha.mc.ntu.edu.tw
Journal
The Lancet