title: Prevalence of hepatitis B surface antigen in vaccinated children and controls in rural Nigeria.
abstract: OBJECTIVE
  To determine the prevalence of hepatitis B surface antigen (HBsAg) amongst vaccinated children and controls aged 1-4 years in a rural community in mid-western Nigeria.
  
  
  METHODS
  The vaccinated children had received at least three doses of hepatitis B vaccine. The vaccines included recombinant hepatitis B vaccine at birth and a combined diphtheria, tetanus, pertussis (whole cell) plus hepatitis B (DTPw-HBV) vaccine. HBsAg was determined by a rapid immunoassay method based on the immunochromatographic sandwich principle. Two hundred and twenty-three children and 219 controls were recruited into the study.
  
  
  RESULTS
  The prevalence of HBsAg was significantly lower in the vaccinated group (1.3%) than in the control group (4.6%, p=0.04). The prevalence rates were significantly higher in males (p=0.02) and two-year birth cohort (p=0.01). The controls were estimated to be at a six-fold higher risk of being positive for the surface antigen than the vaccinated children. The vaccine effectiveness was estimated to be approximately 80%.
  
  
  CONCLUSIONS
  These results confirm that hepatitis B vaccine protects against hepatitis B surface antigen carriage and confirm immunogenicity of the combined DTPw-HBV vaccine.
authors.affiliation: Department of Community Health and Primary Care, Lagos State University College of Medicine, P.M.B. 21266 Ikeja, Nigeria. oolumuyiwa@yahoo.com
authors.forename: O O
authors.initials: OO
authors.lastname: Odusanya
authors.forename: F E
authors.initials: FE
authors.lastname: Alufohai
authors.forename: F P
authors.initials: FP
authors.lastname: Meurice
authors.forename: R
authors.initials: R
authors.lastname: Wellens
authors.forename: J
authors.initials: J
authors.lastname: Weil
authors.forename: V I
authors.initials: VI
authors.lastname: Ahonkhai
mesh_terms: D016022:Case-Control Studies; D002675:Child, Preschool; D018592:Cross-Over Studies; D005260:Female; D006509:Hepatitis B / Q000453:epidemiology / Q000276:immunology* / Q000517:prevention & control; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D017325:Hepatitis B Vaccines / Q000276:immunology* / Q000627:therapeutic use; D006515:Hepatitis B virus / Q000276:immunology*; D006801:Humans; D007118:Immunoassay; D007223:Infant; D008297:Male; D009549:Nigeria / Q000453:epidemiology; D015995:Prevalence; D012424:Rural Population; D014611:Vaccination
chemical_list: D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines