title: Pneumococcal vaccination reduces the risk of community-acquired pneumonia in children.
abstract: BACKGROUND
  The seven-valent pneumococcal conjugate vaccine (PCV7) was introduced to Japan in 2009, after which there was a rapid decline in invasive pneumococcal disease. There are few data, however, on the effectiveness of PCV7 against community-acquired pneumonia (CAP). We conducted an ambispective cohort study among children aged 0-6 years old who attended day-care centers.
  
  
  METHODS
  A total of 624 children at 10 day-care centers in Sapporo, Japan participated in the study. The parents reported whether their child had received PCV7 one or more times, as well as the exact dates of vaccination from records in maternal and child health handbooks marked by pediatricians. Each CAP event was reported by parents according to doctor diagnosis. A Cox proportional hazards regression model was used to calculate the hazard ratio (HR) and 95%CI of CAP incidence reduced by PCV7 inoculation.
  
  
  RESULTS
  During the observational period, 94 subjects contracted CAP. After adjusting for potentially confounding variables, inoculation with PCV7 was significantly associated with a reduced risk of CAP (HR, 0.22; 95%CI: 0.13-0.34). On stratified analysis by age, PCV7 was significantly associated with a reduced risk of CAP in both children aged <3 years (HR, 0.31; 95%CI: 0.14-0.71), and those ≥3 years (HR, 0.20; 95%CI: 0.09-0.43).
  
  
  CONCLUSIONS
  PCV7 is highly effective in reducing the risk of CAP in children attending day-care centers.
authors: Department of Public Health, Sapporo Medical University School of Medicine, Sapporo, Japan.|Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors: Junko
authors: J
authors: Hasegawa
authors: Department of Public Health, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors: Mitsuru
authors: M
authors: Mori
authors: Department of Public Health, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors: Hirofumi
authors: H
authors: Ohnishi
authors: Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors: Takeshi
authors: T
authors: Tsugawa
authors: Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors: Tsukasa
authors: T
authors: Hori
authors: Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors: Yuko
authors: Y
authors: Yoto
authors: Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors: Hiroyuki
authors: H
authors: Tsutsumi
mesh_terms: D002648:Child; D002656:Child Day Care Centers; D002675:Child, Preschool; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000517:prevention & control; D005260:Female; D006306:Health Surveys; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D008297:Male; D011018:Pneumonia, Pneumococcal / Q000453:epidemiology / Q000517:prevention & control*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012189:Retrospective Studies
chemical_list: D000069443:Heptavalent Pneumococcal Conjugate Vaccine
keywords: children; cohort study; effectiveness; pneumococcal conjugate vaccine; pneumonia