title: Pneumococcal Conjugate Vaccine and Clinically Suspected Invasive Pneumococcal Disease.
abstract: OBJECTIVE
  Ten-valent pneumococcal conjugate vaccine (PCV10) was earlier shown to reduce clinically suspected, non-laboratory-confirmed invasive pneumococcal disease (IPD) in a cluster-randomized trial (the Finnish Invasive Pneumococcal disease trial). PCV10 was introduced into the Finnish national vaccination program in September 2010 using a 3-dose schedule. We evaluated the impact of PCV10 on clinically suspected IPD among vaccine-eligible children in a population-based nationwide study.
  
  
  METHODS
  The target cohort eligible for vaccination program (children born June 2010-September 2013) was compared with 2 season- and age-matched (ages 3-42 months) reference cohorts before PCV10 introduction. The trial period (January 2009-August 2010) was excluded. Hospitals' inpatient and outpatient discharge notifications with International Classification of Diseases, 10th Revision, diagnoses compatible with IPD (A40.3/B95.3/G00.1/M00.1) and unspecified sepsis (A40.9/A41.9/A49.9/G00/G00.9/I30.1/M00/M00.9/B95.5) were collected from the national Care Register. Laboratory-confirmed IPD cases were excluded. Rates of register-based non-laboratory-confirmed IPD (or unspecified sepsis) before and after PCV10 implementation were calculated.
  
  
  RESULTS
  The rate of register-based non-laboratory-confirmed IPD episodes was 32 in 100 000 person-years in the vaccine-eligible target cohort and 94 in the combined reference cohorts. Relative rate reduction was 66% (95% confidence interval: 59-73) and absolute rate reduction 62 in 100 000 person-years. For the more sensitive case definition of register-based non-laboratory-confirmed IPD or unspecified sepsis, the relative rate reduction was 34% (95% confidence interval 29-39), but the absolute reduction was as high as 122 in 100 000 person-years.
  
  
  CONCLUSIONS
  This is the first report demonstrating nationwide PCV impact on clinically suspected IPD during routine vaccination program. The large absolute rate reductions observed have major implications for cost-effectiveness of PCVs.
authors.affiliation: Department of Health Protection, National Institute for Health and Welfare, Tampere, Finland; arto.palmu@thl.fi.
authors.forename: Arto A
authors.initials: AA
authors.lastname: Palmu
authors.affiliation: Department of Health Protection, National Institute for Health and Welfare, Helsinki, Finland;
authors.forename: Terhi M
authors.initials: TM
authors.lastname: Kilpi
authors.affiliation: Department of Health Protection, National Institute for Health and Welfare, Helsinki, Finland;
authors.forename: Hanna
authors.initials: H
authors.lastname: Rinta-Kokko
authors.affiliation: Department of Health Protection, National Institute for Health and Welfare, Helsinki, Finland;
authors.forename: Hanna
authors.initials: H
authors.lastname: Nohynek
authors.affiliation: Department of Infectious Diseases, National Institute for Health and Welfare, Helsinki, Finland; and.
authors.forename: Maija
authors.initials: M
authors.lastname: Toropainen
authors.affiliation: Department of Infectious Diseases, National Institute for Health and Welfare, Helsinki, Finland; and Department of Epidemiology, School of Health Sciences, University of Tampere, Finland.
authors.forename: J Pekka
authors.initials: JP
authors.lastname: Nuorti
authors.affiliation: Department of Health Protection, National Institute for Health and Welfare, Helsinki, Finland;
authors.forename: Jukka
authors.initials: J
authors.lastname: Jokinen
mesh_terms: D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D004305:Dose-Response Relationship, Drug; D005387:Finland / Q000453:epidemiology; D005500:Follow-Up Studies; D017589:Immunization Programs; D015994:Incidence; D011008:Pneumococcal Infections / Q000453:epidemiology / Q000517:prevention & control; D022242:Pneumococcal Vaccines / Q000008:administration & dosage / Q000627:therapeutic use; D012189:Retrospective Studies; D013296:Streptococcus pneumoniae / Q000276:immunology; D018074:Vaccines, Conjugate
chemical_list: D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate