title: Efficacy of hepatitis B vaccine boosters among neonatally vaccinated university freshmen in Taiwan.
abstract: OBJECTIVE
  Long-term protection against hepatitis B virus (HBV) after vaccination remains widely debated. We evaluated the efficacy of a modified 3-dose booster protocol in neonatally vaccinated university students in Taiwan.
  
  
  METHODS
  Changes in the levels of antibodies to the hepatitis B surface antigen (anti-HBs) were examined in 250 university students over a 3-year period. Group A (n=39) lacked seroprotective levels of anti-HBs, and declined to receive a booster dose of the HBV vaccine. Group B (n=128) lacked seroprotective levels of anti-HBs, and received booster doses of the HBV vaccine according to a modified 3-dose booster protocol. Group C (n=83) possessed seroprotective levels of anti-HBs, and did not receive a booster dose.
  
  
  RESULTS
  The levels of seroprotective anti-HBs increased in 12.8% of Group A and 14.5% of Group C, suggesting that our entire cohort had experienced booster effects from natural HBV exposure. However, no new HBV infections were observed, and 53.9% of Group B maintained protective levels of anti-HBs during the follow-up period.
  
  
  CONCLUSIONS
  The use of the modified 3-dose booster protocol induced significant long-term increases in the titer of anti-HBs in over 50% of the neonatally vaccinated participants with previously non-protective titers. However, in the absence of a vaccine booster, some neonatally vaccinated people with low anti-HBs titers may nonetheless produce anamnestic responses to HBV upon exposure, suggesting that protection from neonatal vaccination may persist, despite low titers of anti-HBs.
authors.affiliation: School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan.
authors.forename: Fu-Hsiung
authors.initials: FH
authors.lastname: Su
authors.forename: Fang-Yeh
authors.initials: FY
authors.lastname: Chu
authors.forename: Chi-Hui
authors.initials: CH
authors.lastname: Bai
authors.forename: Yu-Shiang
authors.initials: YS
authors.lastname: Lin
authors.forename: Yu-Mei
authors.initials: YM
authors.lastname: Hsueh
authors.forename: Fung-Chang
authors.initials: FC
authors.lastname: Sung
authors.forename: Chih-Ching
authors.initials: CC
authors.lastname: Yeh
mesh_terms: D015331:Cohort Studies; D005260:Female; D006509:Hepatitis B / Q000276:immunology / Q000517:prevention & control; D006510:Hepatitis B Antibodies / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000276:immunology; D017325:Hepatitis B Vaccines / Q000008:administration & dosage*; D006801:Humans; D007115:Immunization Schedule; D007117:Immunization, Secondary / Q000379:methods*; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D013334:Students; D013624:Taiwan; D016896:Treatment Outcome; D014495:Universities; D055815:Young Adult
chemical_list: D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines