title: Seroprevalence of anti-HBs antibodies at young adulthood, before and after a booster vaccine dose, among medical personnel vaccinated in infancy.
abstract: BACKGROUND
  Questions remain regarding the long-term protection provided by childhood HBV vaccination. The goals of this study were to assess HBV seroprevalence among medical personnel purportedly vaccinated in infancy; to investigate the immune response after a booster dose given in young adulthood; and to identify predictors of non-responders.
  
  
  METHODS
  Between 2011 and 2013 we studied Israeli male military recruits purportedly vaccinated in infancy. All subjects were born after January 1st 1992 and were undergoing medic training. We collected personal data and blood samples at baseline, and administered a dose of HBV vaccine. Subjects were retested one month later and received a second dose. A third blood draw was conducted one month after the second dose. Data collected at baseline were used as predictor variables of seropositivity (anti-HBs≥10mIU/ml).
  
  
  RESULTS
  617 subjects were available for baseline analysis and 539 for paired observations at one month. Baseline seropositivity was 33.7%. Subjects who received post-infancy vaccine doses had a seropositivity rate double that of those denying additional doses (RR 2.22, 95% CI 1.55-3.18). One month after the first booster dose, the overall cumulative population seropositivity reached 87.7%. One month after the second vaccine dose, population seropositivity was 97.9%. Heavy smokers were 5 times less likely to demonstrate detectable antibodies after a single booster dose (OR 0.196, 95% CI 0.060-0.641, P=0.007).
  
  
  CONCLUSIONS
  This population-based study is important for informing public health vaccination policy. Our results strongly indicate that among cohorts vaccinated in infancy, two doses in adulthood will provide maximal protective antibody levels, while one dose will provide sufficient population protection.
authors.affiliation: IDF Medical Corps, Israel; Department of Military Medicine, Hebrew University Faculty of Medicine, Jerusalem, Israel. Electronic address: hartal4@gmail.com.
authors.forename: Michael
authors.initials: M
authors.lastname: Hartal
authors.affiliation: IDF Medical Corps, Israel.
authors.forename: Nirit
authors.initials: N
authors.lastname: Yavnai
authors.affiliation: IDF Medical Corps, Israel.
authors.forename: Inbal
authors.initials: I
authors.lastname: Galor
authors.affiliation: IDF Medical Corps, Israel.
authors.forename: Eva
authors.initials: E
authors.lastname: Avramovich
authors.affiliation: IDF Medical Corps, Israel.
authors.forename: Tamar
authors.initials: T
authors.lastname: Sela
authors.affiliation: IDF Medical Corps, Israel.
authors.forename: Raeed
authors.initials: R
authors.lastname: Kayouf
authors.affiliation: IDF Medical Corps, Israel.
authors.forename: Anat
authors.initials: A
authors.lastname: Tzurel-Ferber
authors.affiliation: IDF Medical Corps, Israel; University of Rochester Medical Center, Rochester, NY, USA.
authors.forename: Lior J
authors.initials: LJ
authors.lastname: Greenberg
authors.affiliation: IDF Medical Corps, Israel.
authors.forename: Tami
authors.initials: T
authors.lastname: Halperin
authors.affiliation: IDF Medical Corps, Israel; Hebrew University - Hadassah Braun School of Public Health and Community Medicine, Jerusalem, Israel.
authors.forename: Hagai
authors.initials: H
authors.lastname: Levine
mesh_terms: D015331:Cohort Studies; D006282:Health Personnel; D006510:Hepatitis B Antibodies / Q000097:blood*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage*; D006801:Humans; D007557:Israel; D008297:Male; D016036:Seroepidemiologic Studies; D055815:Young Adult
chemical_list: D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines
keywords: Booster; Healthcare workers; Hepatitis B; Seroprevalence; Vaccine