title: Tuberculin reaction and BCG scar: association with infant mortality.
abstract: OBJECTIVE
  To test the hypothesis that having a scar and a positive tuberculin skin test (TST) response after vaccination with Bacille Calmette-Guérin (BCG) is associated with reduced infant mortality.
  
  
  METHODS
  We studied cohorts of 2709 normal-birthweight (NBW) and 1102 low-birthweight (LBW) infants in Guinea-Bissau. Children were enrolled in randomised trials between year 2002 and 2008 and received BCG vaccination at birth. BCG scars and TST responses were assessed at 2 and 6 months of age. The infants were followed for mortality to 12 months of age, and survival was analysed using Cox regression.
  
  
  RESULTS
  At age 2 months, 88% of NBW children and 91% of LBW children had a BCG scar, and 36% and 17% had a TST response, respectively. The LBW infants had nearly twofold higher mortality (4.5%) than the NBW infants (2.8%) between 2 and 12 months of age. In the LBW cohort, the adjusted mortality rate ratio (MRR) comparing children with a BCG scar with those without was 0.42 (95% CI = 0.19; 0.93). There was a similar tendency for TST positivity: MRR = 0.47 (95% CI = 0.14; 1.54). For LBW children who had both a positive TST reaction and a scar, the MRR was 0.22 (95% CI = 0.05; 0.87). For NBW children, a scar and a positive TST were associated with 20% reductions in mortality, which did not reach statistical significance.
  
  
  CONCLUSIONS
  We confirmed previous observations that having a scar and a TST response after BCG vaccination is associated with lower mortality risk. The possibility of revaccinating scar-negative children should be considered.
authors.affiliation: Department of Environmental Medicine, Institute of Public Health, University of Southern Denmark, Odense, Denmark.
authors.forename: Clara Amalie Gade
authors.initials: CA
authors.lastname: Timmermann
authors.affiliation: Research Centre for Vitamins and Vaccines, Bandim Health Project, Bissau, Guinea-Bissau.|Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau.
authors.forename: Sofie
authors.initials: S
authors.lastname: Biering-Sørensen
authors.affiliation: Research Centre for Vitamins and Vaccines, Bandim Health Project, Bissau, Guinea-Bissau.|Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau.
authors.forename: Peter
authors.initials: P
authors.lastname: Aaby
authors.affiliation: Research Centre for Vitamins and Vaccines, Bandim Health Project, Bissau, Guinea-Bissau.|Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau.
authors.forename: Ane Baerent
authors.initials: AB
authors.lastname: Fisker
authors.affiliation: Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau.
authors.forename: Ivan
authors.initials: I
authors.lastname: Monteiro
authors.affiliation: Research Centre for Vitamins and Vaccines, Bandim Health Project, Bissau, Guinea-Bissau.|Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau.
authors.forename: Amabelia
authors.initials: A
authors.lastname: Rodrigues
authors.affiliation: Research Centre for Vitamins and Vaccines, Bandim Health Project, Bissau, Guinea-Bissau.|OPEN, Institute of Clinical Research, University of Southern Denmark/Odense University Hospital, Odense, Denmark.
authors.forename: Christine Stabell
authors.initials: CS
authors.lastname: Benn
authors.affiliation: Research Centre for Vitamins and Vaccines, Bandim Health Project, Bissau, Guinea-Bissau.|OPEN, Institute of Clinical Research, University of Southern Denmark/Odense University Hospital, Odense, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Ravn
mesh_terms: D001500:BCG Vaccine / Q000276:immunology*; D001724:Birth Weight; D002921:Cicatrix; D015331:Cohort Studies; D005260:Female; D006169:Guinea-Bissau; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D008297:Male; D016016:Proportional Hazards Models; D014373:Tuberculin / Q000276:immunology* / Q000378:metabolism; D014374:Tuberculin Test; D014611:Vaccination
chemical_list: D001500:BCG Vaccine; D014373:Tuberculin
keywords: BCG scar; BCG vaccine; Guinea-Bissau; infant mortality; tuberculin skin test