title: Immunogenicity of low doses of recombinant hepatitis B vaccine in young males.
abstract: A trial of low doses (1.25 and 0.625 micrograms) of recombinant hepatitis B vaccine in 110 males aged 17-19 years is reported. Follow-up was extended to one year and further data are reported for participants from earlier trials of 10, 5 and 2.5 microgram doses for comparison. Seroconversion rates after the booster dose were 94% at 1.25 micrograms and 89% at 0.625 micrograms, compared to 100% at higher doses. Geometric mean titres (GMT) of antibody to hepatitis B surface antigen (anti-HBs) were significantly lower with the 0.625 microgram dose than with 1.25 micrograms at all times, reaching a GMT of 42.6 IU l-1 and 152.9 l-1, respectively, after the booster dose. GMT values at 12 months were 513.9, 510.0, 320.7, 46.5 and 13.3 IU l-1 in the 10, 5, 2.5, 1.25 and 0.625 microgram dose groups, respectively. Increases in GMT after the booster dose were parallelled in all groups. GMT decreased by approximately equal to 65% between 7 and 12 months in the three lowest dose groups, significantly less than the fall of 80% at 5 and 10 micrograms. However, to secure variability among vaccinees, the minimum effective dose for young adults should be greater than 5 micrograms per dose.
authors.affiliation: National Centre for Viral Hepatitis, Athens School of Hygiene, Greece.
authors.forename: C
authors.initials: C
authors.lastname: Tsakalakis
authors.forename: S C
authors.initials: SC
authors.lastname: Richardson
authors.forename: A
authors.initials: A
authors.lastname: Roumeliotou-Karayannis
authors.forename: G
authors.initials: G
authors.lastname: Papaevangelou
mesh_terms: D000293:Adolescent; D000328:Adult; D006510:Hepatitis B Antibodies / Q000096:biosynthesis*; D006512:Hepatitis B Core Antigens / Q000276:immunology; D006514:Hepatitis B Surface Antigens / Q000032:analysis / Q000276:immunology; D017325:Hepatitis B Vaccines; D006515:Hepatitis B virus / Q000276:immunology*; D006801:Humans; D007117:Immunization, Secondary; D008297:Male; D008889:Military Personnel; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D014612:Vaccines / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology*; D014761:Viral Hepatitis Vaccines / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D006510:Hepatitis B Antibodies; D006512:Hepatitis B Core Antigens; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines; D014612:Vaccines; D014614:Vaccines, Synthetic; D014761:Viral Hepatitis Vaccines