title: Prophylactic vaccination against hepatitis B: achievements, challenges and perspectives.
abstract: Large-scale vaccination against hepatitis B virus (HBV) infection started in 1984 with first-generation vaccines made from plasma of chronic carriers containing HBV surface antigen (HBsAg). Thereafter, it was replaced in most countries by second-generation vaccines manufactured in yeast cells transformed with gene S encoding HBsAg. Both generations of vaccines have been applied for universal neonate and early childhood vaccination worldwide and have led to a 70-90 % decrease in chronic HBV carrier rates. However, 10-30% of newborns from HBsAg/HBeAg-positive mothers cannot be protected by passive/active vaccination alone and become chronic HBV carriers themselves. Asymptomatic occult HBV infections are frequent even in those who have protective levels of anti-HBs. Suboptimal protection may be due to heterologous HBsAg subtypes that are present in 99% of HBV carriers worldwide. Second-generation vaccines contain partially misfolded HBsAg and lack preS1 antigen that carries the major HBV attachment site and neutralizing epitopes. Third-generation vaccines produced in mammalian cells contain correctly folded HBsAg and neutralizing epitopes of the preS antigens, induce more rapid protection, overcome nonresponse to second-generation vaccines and, most importantly, may provide better protection for newborns of HBV-positive mothers. PreS/S vaccines expressed in mammalian cells are more expensive to manufacture, but introduction of more potent HBV vaccines should be considered in regions with a high rate of vertical transmission pending assessment of health economics and healthcare priorities. With optimal vaccines and vaccination coverage, eradication of HBV would be possible.
authors.affiliation: Institute for Medical Virology, National Reference Center for Hepatitis B and D, Justus-Liebig-University Giessen, Schubert Str. 81, 35392, Giessen, Germany, wolfram.h.gerlich@viro.med.uni-giessen.de.
authors.forename: Wolfram H
authors.initials: WH
authors.lastname: Gerlich
mesh_terms: D002353:Carrier State / Q000453:epidemiology / Q000517:prevention & control*; D006509:Hepatitis B / Q000453:epidemiology / Q000517:prevention & control*; D006514:Hepatitis B Surface Antigens / Q000276:immunology; D017325:Hepatitis B Vaccines / Q000276:immunology* / Q000302:isolation & purification*; D006801:Humans; D011498:Protein Precursors / Q000276:immunology; D014611:Vaccination / Q000379:methods*
chemical_list: D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines; D011498:Protein Precursors