title: Development of BCG Scar and Subsequent Morbidity and Mortality in Rural Guinea-Bissau.
abstract: BACKGROUND
  Previous studies have found that BCG vaccination has nonspecific beneficial effects on child survival, especially among children who developed a BCG scar. These studies have mostly been done in settings with a high scar frequency. In rural Guinea-Bissau, many children do not develop a scar; we tested the hypothesis that among BCG-vaccinated children, a vaccination scar was associated with lower mortality and fewer hospital admissions.
  
  
  METHODS
  During 2009-2011, children <5 years of age in villages followed by Bandim Health Project's demographic surveillance system had their scar status assessed at semiannual visits. We compared mortality and hospital admission rates of scar-positive and scar-negative BCG-vaccinated children during 6 months of follow-up in Cox proportional hazards models.
  
  
  RESULTS
  Among 15 911 BCG-vaccinated children, only 52% had a scar. There were 106 non-injury-related deaths among scar-positive children and 137 among scar-negative children. The mortality rate ratio (MRR) was 0.74 (95% confidence interval [CI], .56-.96) overall; 0.48 (95% CI, .26-.90) in infancy, 0.69 (95% CI, .45-1.05) in the second year of life, and 0.89 (95% CI, .61-1.31) in the third-fifth year of life. The association between scar positivity and lower mortality differed significantly by cause of death and was strongest for respiratory infections (MRR, 0.20 [95% CI, .07-.55]). There were 99 hospital admissions among scar-positive children and 125 admissions among scar-negative children, resulting in an incidence rate ratio of 0.74 (95% CI, .60-.92).
  
  
  CONCLUSIONS
  Among BCG-vaccinated children in a setting with low scar prevalence, having a scar is associated with lower mortality and morbidity. BCG scar prevalence may be an important marker of vaccination program quality.
authors.affiliation: Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau Research Center for Vitamins and Vaccines, Bandim Health Project, Statens Serum Institut, Copenhagen.
authors.forename: Line
authors.initials: L
authors.lastname: Storgaard
authors.affiliation: Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau.
authors.forename: Amabelia
authors.initials: A
authors.lastname: Rodrigues
authors.affiliation: Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau.
authors.forename: Cesario
authors.initials: C
authors.lastname: Martins
authors.affiliation: Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau Research Center for Vitamins and Vaccines, Bandim Health Project, Statens Serum Institut, Copenhagen.
authors.forename: Bibi Uhre
authors.initials: BU
authors.lastname: Nielsen
authors.affiliation: Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau Research Center for Vitamins and Vaccines, Bandim Health Project, Statens Serum Institut, Copenhagen Odense Patient data Explorative Network, Institute of Clinical Research, University of Southern Denmark/Odense University Hospital.
authors.forename: Henrik
authors.initials: H
authors.lastname: Ravn
authors.affiliation: Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau Research Center for Vitamins and Vaccines, Bandim Health Project, Statens Serum Institut, Copenhagen Odense Patient data Explorative Network, Institute of Clinical Research, University of Southern Denmark/Odense University Hospital.
authors.forename: Christine Stabell
authors.initials: CS
authors.lastname: Benn
authors.affiliation: Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau Research Center for Vitamins and Vaccines, Bandim Health Project, Statens Serum Institut, Copenhagen Odense Patient data Explorative Network, Institute of Clinical Research, University of Southern Denmark/Odense University Hospital.
authors.forename: Peter
authors.initials: P
authors.lastname: Aaby
authors.affiliation: Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau Research Center for Vitamins and Vaccines, Bandim Health Project, Statens Serum Institut, Copenhagen.
authors.forename: Ane Bærent
authors.initials: AB
authors.lastname: Fisker
mesh_terms: D001500:BCG Vaccine / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology*; D002675:Child, Preschool; D002921:Cicatrix / Q000139:chemically induced* / Q000453:epidemiology*; D015331:Cohort Studies; D003141:Communicable Diseases / Q000401:mortality* / Q000473:pathology*; D005260:Female; D006169:Guinea-Bissau / Q000453:epidemiology; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D012424:Rural Population; D016019:Survival Analysis
chemical_list: D001500:BCG Vaccine
keywords: BCG scar; BCG vaccine; child mortality; heterologous immunity; nonspecific effects of vaccines