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Document Details : Title: Prevention of hepatitis B infections: vaccination and its limitations Author(s): LEROUX-ROELS G, CAO T, DE KNIBBER A, MEULEMAN P, ROOBROUCK A, FARHOUDI A, VANLANDSCHOOT P, DESOMBERE I Journal: Acta Clinica Belgica Volume: 56 Issue: 4 Date: 2001 Pages: 209-219 DOI: 10.2143/ACB.56.4.1002851 Abstract : Infection with hepatitis B virus has become a vaccine-preventable disease. The recombinant hepatitis B vaccines available today are safe and immunogenic. In order for these vaccines to eradicate HBV a universal vaccination of neonates and/or children needs to be implemented. Major obstacles on the road to global hepatitis B vaccination are poverty and scarcity of human resources in those parts of the world who are most badly in need of these vaccines. Despite their proven immunogenicity hepatitis B vaccines are unable to induce an adequate immune response in 5-10% of healthy adults. The non-responsiveness of these subjects is a selective phenomenon and not the expression of a general immune deficiency. Studies that correlated the HLA haplotype of vaccine recipients with their anti-HBs response patterns has led to the identificiation of markers of good and non/poor response. Universal vaccination of neonates and children has elicited questions about the durability of antibody persistence and the need for booster doses later in life. The European Consensus Group on Hepatitis B Immunity has proposed a series of recommendations that are summarized in this review. An important mutation in HBsAg has been reported some 10 years ago. Since then such variants have been found in many countries but their importance and possible impact on public health remains controversial. On the one hand epidemiological surveys and a mathematical model predict a progressive disappearance of the wild-type HBV and the emergence of the G145R mutant as the common HBV in another 60 to 100 years. On the other hand vaccination studies in chimpanzees and analysis of vaccine-induced antibodies demonstrate that the recombinant hepatitis B vaccines available today convey protective immunity not only against the wildtype virus but against the commonly occurring HBsAg mutants as well. Infections with hepatitis B virus (HBV) represent a major health problem. More than 2 billion individuals worldwide have evidence of past or current infection with HBV. Over 350 million people are estimated to be chronically infected with this virus and it is estimated that 75-100 million of them will die of liver cirrhosis and/or hepatocellular carcinoma. Current therapies for HBV infection, although becoming increasingly effective, remain problematic because of side effects and high cost which makes them inaccessible for the many millions of patients in developing countries. Because of the morbidity of the disease and its impact on individual and society, the quest for a HB vaccine was started soon after its identification in 1970. A plasma-derived hepatitis B vaccine was licensed in the United States in 1981 and a recombinant vaccine was launched in 1986. Meanwhile hundreds of millions of vaccine doses have been administered. The different vaccines turned out to be safe and immunogenic. They are very efficacious and have drastically reduced the occurrence of hepatitis B infections in the targeted populations. Although the story of the hepatitis B vaccine is one of unequivocal success, some issues of concern still remain and novel problems appear at the horizon. |
