title: Serotype distribution in non-bacteremic pneumococcal pneumonia: association with disease severity and implications for pneumococcal conjugate vaccines.
abstract: BACKGROUND
  There is limited knowledge of serotypes that cause non-bacteremic pneumococcal pneumonia (NBP). Here we report serotypes, their associated disease potential and coverage of pneumococcal conjugate vaccines (PCV) in adults with NBP and compare these to bacteremic pneumonia (BP).
  
  
  METHODS
  Adults with pneumonia and Streptococcus pneumoniae isolated from the lower respiratory tract or blood were included 1 year in a population-based design in Denmark. Pneumonia was defined as a new infiltrate on chest radiograph in combination with clinical symptoms or elevated white blood count or plasma C-reactive protein. All isolates were serotyped using type-specific pneumococcal rabbit antisera. All values are medians with interquartile ranges.
  
  
  RESULTS
  There were 272 cases of NBP and 192 cases of BP. Ninety-nine percent were hospitalized. NBP and BP cases were of comparable age and sex but NBP cases had more respiratory symptoms and less severe disease compared to BP cases. In total, 46 different serotypes were identified. Among NBP cases, 5 serotypes accounted for nearly a third of isolates. PCV10 and -13 types covered 17% (95% confidence interval (CI): 11-23%) and 34% (95% CI: 25-43%) of NBP isolates, respectively. In contrast, the five most frequent serotypes accounted for two-thirds of BP isolates. PCV10 and -13 types covered 39% (95% CI: 30-48%) and 64% (95% CI: 48-79) of BP isolates, respectively. More severe NBP disease was associated with infection with invasive serotypes while there was an inverse relationship for BP.
  
  
  CONCLUSIONS
  Only a third of cases of adult non-bacteremic pneumococcal pneumonia would potentially be preventable with the use of PCV13 and just one sixth of cases with the use of PCV10 indicating that PCVs with increased valency are needed to increase vaccine coverage for NBP in adults. PCV13 could potentially prevent two-thirds of adult bacteremic pneumococcal pneumonia.
authors.affiliation: Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre, Denmark. tlb@dadlnet.dk
authors.forename: Thomas
authors.initials: T
authors.lastname: Benfield
authors.forename: Marlene
authors.initials: M
authors.lastname: Skovgaard
authors.forename: Henrik Carl
authors.initials: HC
authors.lastname: Schønheyder
authors.forename: Jenny Dahl
authors.initials: JD
authors.lastname: Knudsen
authors.forename: Jette
authors.initials: J
authors.lastname: Bangsborg
authors.forename: Christian
authors.initials: C
authors.lastname: Østergaard
authors.forename: Hans-Christian
authors.initials: HC
authors.lastname: Slotved
authors.forename: Helle Bossen
authors.initials: HB
authors.lastname: Konradsen
authors.forename: Reimar Wernich
authors.initials: RW
authors.lastname: Thomsen
authors.forename: Lotte
authors.initials: L
authors.lastname: Lambertsen
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D022242:Pneumococcal Vaccines / Q000276:immunology; D011018:Pneumonia, Pneumococcal / Q000453:epidemiology / Q000382:microbiology* / Q000517:prevention & control; D012703:Serotyping; D012720:Severity of Illness Index; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000276:immunology; D018074:Vaccines, Conjugate / Q000276:immunology; D055815:Young Adult
chemical_list: D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate