title: BCG vaccination scar associated with better childhood survival in Guinea-Bissau.
abstract: BACKGROUND
  Recent studies have suggested that Bacille Calmette-Guerin (BCG) vaccination may have a non-specific beneficial effect on infant survival and that a BCG scar may be associated with lower child mortality. No study has previously examined the influence of BCG vaccination on cause of death.
  
  
  METHODS
  Two cohorts (A and B) were used to describe the mortality pattern for children with and without BCG scar and to determine specific causes of death. In cohort A (n = 1813), BCG scar was assessed at 6 months of age and as previously described children with a BCG scar had lower mortality over the next 12 months than children with no BCG scar. In cohort B, 1617 children aged 3 months to 5 years of age had their BCG scar status assessed in a household-based survey and mortality was assessed during a 12-month period. Causes of death were determined by verbal autopsy (VA) and related to BCG scar status in a cause-specific hazard function.
  
  
  RESULTS
  Controlling for background factors associated with mortality, there was lower mortality for children with a BCG scar than without in cohort B, the mortality ratio (MR) being 0.45 (95% CI 0.21-0.96). Exclusion of children exposed to TB did not have any impact on the result. In a combined analysis of cohorts A and B, the MR was 0.43 (95% CI 0.28-0.65) controlling for background factors. There were no large differences in distribution of the five major causes of death (malaria, pneumonia, acute diarrhoea, chronic diarrhoea, and meningitis/encephalitis) according to BCG scar status in the two cohorts. Having a BCG scar significantly reduced the risk of death from malaria [MR 0.32 (95% CI 0.13-0.76)].
  
  
  CONCLUSIONS
  A BCG scar is a marker of better survival among children in countries with high child mortality. BCG vaccination may affect the response to several major infections including malaria.
authors.affiliation: Bandim Health Project, Apartado 861, Bissau, Guinea-Bissau. aro@ssi.dk
authors.forename: Adam
authors.initials: A
authors.lastname: Roth
authors.forename: Per
authors.initials: P
authors.lastname: Gustafson
authors.forename: Alexandro
authors.initials: A
authors.lastname: Nhaga
authors.forename: Queba
authors.initials: Q
authors.lastname: Djana
authors.forename: Anja
authors.initials: A
authors.lastname: Poulsen
authors.forename: May-Lill
authors.initials: ML
authors.lastname: Garly
authors.forename: Henrik
authors.initials: H
authors.lastname: Jensen
authors.forename: Morten
authors.initials: M
authors.lastname: Sodemann
authors.forename: Amabelia
authors.initials: A
authors.lastname: Rodriques
authors.forename: Peter
authors.initials: P
authors.lastname: Aaby
mesh_terms: D001500:BCG Vaccine / Q000008:administration & dosage*; D002423:Cause of Death; D046688:Child Mortality; D002675:Child, Preschool; D002921:Cicatrix / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006169:Guinea-Bissau / Q000453:epidemiology; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D008297:Male; D012044:Regression Analysis; D014376:Tuberculosis / Q000517:prevention & control
chemical_list: D001500:BCG Vaccine