title: Pneumococcal vaccination reduced the risk of acute otitis media: Cohort study.
abstract: BACKGROUND
  Seven-valent pneumococcal conjugate vaccine (PCV7) was introduced to Japan in 2009, and after that invasive pneumococcal disease has gradually decreased. There are few data, however, on the effectiveness of PCV7 against acute otitis media (AOM) in Japan.
  
  
  METHODS
  From 10 daycare centers in Sapporo, Japan, 614 parents participated in the survey. Each parent reported whether their child subject had received one or more doses of PCV7, and, if so, the exact dates of receiving PCV7 were verified by reviewing their maternal and child health handbooks marked by a pediatrician. AOM was diagnosed by otorhinolaryngologist or pediatrician. Cox's proportional hazard model was used for calculating the hazard ratio (HR) of AOM incidence reduced by PCV7 inoculation.
  
  
  RESULTS
  Inoculation of PCV7 significantly reduced the risk of AOM (crude HR, 0.63; 95%CI: 0.50-0.79). Adjusting for potentially confounding variables reduced the risk further (adjusted HR, 0.32; 95%CI: 0.23-0.44). On stratification by subject age on 30 April 2012, PCV7 was significantly associated with a reduced risk of AOM in both infants < 3 years old, and in children ≥ 3 years.
  
  
  CONCLUSIONS
  PCV7 is effectiveness in reducing the risk of AOM both in infants < 3 years old, and in young children ≥ 3 years in Japan.
authors.affiliation: Department of Public Health, Sapporo Medical University School of Medicine, Sapporo, Japan.|Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Hasegawa
authors.affiliation: Department of Public Health, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Mori
authors.affiliation: Department of Public Health, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Satoko
authors.initials: S
authors.lastname: Showa
authors.affiliation: Department of Public Health, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Aiko
authors.initials: A
authors.lastname: Matsushima
authors.affiliation: Department of Public Health, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Ohnishi
authors.affiliation: Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tsugawa
authors.affiliation: Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Yoto
authors.affiliation: Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsutsumi
mesh_terms: D000208:Acute Disease; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D000069443:Heptavalent Pneumococcal Conjugate Vaccine / Q000494:pharmacology*; D006801:Humans; D015994:Incidence; D007223:Infant; D007564:Japan / Q000453:epidemiology; D008297:Male; D010033:Otitis Media / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control*; D011008:Pneumococcal Infections / Q000453:epidemiology / Q000517:prevention & control*; D011446:Prospective Studies; D012189:Retrospective Studies; D013296:Streptococcus pneumoniae / Q000276:immunology*; D014611:Vaccination / Q000379:methods*; D018074:Vaccines, Conjugate
chemical_list: D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D018074:Vaccines, Conjugate
keywords: acute otitis media; children; cohort study; effectiveness; pneumococcal conjugate vaccine