title: Immunogenicity and reactogenicity of a recombinant hepatitis B vaccine in subjects over age of forty years and response of a booster dose among nonresponders.
abstract: OBJECTIVE
  The study was initiated to evaluate the reactogenicity and immunogenicity of a recombinant hepatitis B vaccine in age group >40 years and to study the response of a single booster dose in primary non-responders to the hepatitis B vaccination.
  
  
  METHODS
  A total of 102 volunteers without markers of hepatitis B infection (negative for HBsAg, anti-HBc antibody, HBeAg and anti-HBs antibody) received 20 microg of recombinant HB vaccine intramuscularly at 0, 1, and 6 months. Anti HBs titers were evaluated by a quantitative Elisa kit at 90 and 210 days. A booster dose of 20 microg HB vaccine was given after 6 months of the 3(rd) vaccine dose to the 15 non-responders and anti-HBs titers were measured after 1 month.
  
  
  RESULTS
  Seroprotection (anti-HBs GMT(3) 10 IU/L) was achieved in 85.3 % (87/102) volunteers. The mean GMT titers of the vaccine responders was 136.1 IU/L. Of the seroprotected individuals, there were 32.4 % (33/102) hyporesponders (anti-HBs titers <10-99 mlU/ml) and 52.9 % (54/102) were responders (anti-HBs titers >100 IU/L). All the non-responders (15/15) responded to a single dose of the booster dose of recombinant HB vaccine and their mean anti-HBs antibody titers were more than 100.5 mIU/ml after the booster dose.
  
  
  CONCLUSIONS
  Recombinant hepatitis B vaccine offers good seroprotection in the age group >40 years and has a good safety profile. A single booster dose after 6 months in primary non-responders leads to good seroprotective anti-HBs antibody titers. However, larger population based studies are needed to evaluate the role of a booster dose in selected group of non-responders and whether such an approach will be cost effective.
authors.affiliation: Professor of Medicine, Maulana Azad Medical College & L.N. Hospital, New Delhi-110002, India.
authors.forename: Kunal
authors.initials: K
authors.lastname: Das
authors.forename: R K
authors.initials: RK
authors.lastname: Gupta
authors.forename: V
authors.initials: V
authors.lastname: Kumar
authors.forename: P
authors.initials: P
authors.lastname: Kar
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D005260:Female; D006510:Hepatitis B Antibodies / Q000097:blood; D017325:Hepatitis B Vaccines / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology*; D006801:Humans; D007117:Immunization, Secondary; D008297:Male; D008875:Middle Aged; D012449:Safety; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology
chemical_list: D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines; D014614:Vaccines, Synthetic