title: Has the incidence of empyema in Scottish children continued to increase beyond 2005?
abstract: BACKGROUND
  The incidence of empyema increased dramatically in children during the 1990s and early 2000s. We investigated the relationship between changes in the incidence of childhood empyema in Scotland following the 2006 introduction of routine heptavalent conjugate pneumococcal vaccination (PCv-7) and the 2010 introduction of the 13-valent (PCV-13) vaccine.
  
  
  METHODS
  This was a whole-population study of Scottish hospital admissions between 1981 and 2013 using ICD (International Classification of Diseases)-9 and ICD-10 diagnostic codes for empyema. The number of admissions for pneumonia and croup was also captured to give insight into secular trends in admissions with other related and unrelated respiratory presentations.
  
  
  RESULTS
  There were 217 admissions with empyema between 1981 and 2005 (mean incidence 9 cases/million/year) and 323 between 2006 and 2013 (mean incidence 47 cases/million/year), p<0.001. The introduction of conjugate vaccines in 2006 was associated with an overall increase in admissions for empyema of 2.0 (95% CI 1.4 to 2.8) per 100 000 children, however, the incidence rate ratio for empyema admission between 2010 and 2013 was lower relative to 2006-2009 (0.78 (95% CI 0.63 to 0.98)). Secular changes in pneumonia, but not croup, were comparable with those for empyema.
  
  
  CONCLUSIONS
  The incidence of empyema in Scottish children initially rose in children aged 1 to 9 years after the introduction of routine conjugate pneumococcal vaccination, however, empyema incidence has fallen since 2010 when the PCV-13 was introduced.
authors.affiliation: Department of Child Health, University of Aberdeen, Aberdeen, UK.
authors.forename: Stuart
authors.initials: S
authors.lastname: Nath
authors.affiliation: Department of Respiratory Paediatrics, Newcastle-upon-Tyne Hospitals NHS Trust, Newcastle-upon-Tyne, UK Institute for Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
authors.forename: Matt
authors.initials: M
authors.lastname: Thomas
authors.affiliation: Department of Respiratory Paediatrics, Newcastle-upon-Tyne Hospitals NHS Trust, Newcastle-upon-Tyne, UK.
authors.forename: David
authors.initials: D
authors.lastname: Spencer
authors.affiliation: Department of Child Health, University of Aberdeen, Aberdeen, UK.
authors.forename: Steve
authors.initials: S
authors.lastname: Turner
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004653:Empyema / Q000453:epidemiology* / Q000517:prevention & control; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D022242:Pneumococcal Vaccines / Q000008:administration & dosage; D011018:Pneumonia, Pneumococcal / Q000517:prevention & control; D012606:Scotland / Q000453:epidemiology
chemical_list: C538862:13-valent pneumococcal vaccine; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines
keywords: Epidemiology; Infectious Diseases; Respiratory