title: Lower prevalence of tuberculosis infection in BCG vaccinees: a cross-sectional study in adult prison inmates.
abstract: OBJECTIVE
  To address whether the effect of BCG vaccination against tuberculosis (TB) infection lasts to adulthood.
  
  
  METHODS
  A cross-sectional study on the prevalence of latent TB infection (LTBI) among HIV-negative men, using QuantiFERON-TB Gold In-tube (QFT-IT), was conducted at a prison in northern Taiwan with >3000 inmates. A QFT-IT ≥0.35 IU/ml was defined as LTBI. A QFT-IT ≥0.7 IU/ml was defined as recent LTBI. The association between the number of BCG scars and LTBI stratified by age was analysed. The study procedure was approved by the institutional review board, and all participants gave written informed consent before receiving screening tests.
  
  
  RESULTS
  Among the 2385 participants, 25% had a QFT-IT ≥0.35 IU/ml. Increasing LTBI (14%, 32% and 50%) was observed with increased age (18-34 years, 35-54 years and ≥55 years) (p<0.001 by the Cochran-Armitage Trend Test). The number of BCG scars were found to be inversely correlated with QFT-IT results for both LTBI and recent LTBI in all three age groups (p<0.001 by Cochran-Mantel-Haenszel statistics).
  
  
  CONCLUSIONS
  Our results suggest that BCG vaccine seems to have a protective effect in adults decades after vaccination according to the number of recent infections (QFT-IT ≥0.7 IU/ml). This finding has important implications for national policy of BCG vaccination. Further prospective cohort studies on the protective effect of BCG vaccination against TB infection in adults are warranted.
authors.affiliation: Third Division, Centers for Disease Control, Taipei, Taiwan.
authors.forename: Pei-Chun
authors.initials: PC
authors.lastname: Chan
authors.forename: Chin-Hui
authors.initials: CH
authors.lastname: Yang
authors.forename: Luan-Yin
authors.initials: LY
authors.lastname: Chang
authors.forename: Kwei-Feng
authors.initials: KF
authors.lastname: Wang
authors.forename: Yi-Chen
authors.initials: YC
authors.lastname: Kuo
authors.forename: Chou-Jui
authors.initials: CJ
authors.lastname: Lin
authors.forename: Shih-Wei
authors.initials: SW
authors.lastname: Lee
authors.forename: Po-Ren
authors.initials: PR
authors.lastname: Hsueh
authors.forename: Chi-Tai
authors.initials: CT
authors.lastname: Fang
authors.forename: Li-Min
authors.initials: LM
authors.lastname: Huang
mesh_terms: D000276:Adjuvants, Immunologic; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001500:BCG Vaccine; D003430:Cross-Sectional Studies; D006801:Humans; D059425:Interferon-gamma Release Tests; D055985:Latent Tuberculosis / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011330:Prisons; D013624:Taiwan / Q000453:epidemiology; D014374:Tuberculin Test; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control*; D055815:Young Adult
chemical_list: D000276:Adjuvants, Immunologic; D001500:BCG Vaccine