title: The impact of the heptavalent pneumococcal conjugate vaccine on risk factors for Streptococcus pneumoniae carriage in children.
abstract: BACKGROUND
  The aim of the study was to investigate whether the 7-valent pneumococcal conjugate vaccine (PCV7) alters common risk factors of nasopharyngeal carriage by Streptococcus pneumoniae in children.
  
  
  METHODS
  From July 2005 through December 2010, we performed a cross-sectional study investigating risk factors associated with pneumococcal carriage in children. Parents of participating children completed questionnaires including whether or not the children received PCV7 vaccination.
  
  
  RESULTS
  Among 9705 children, 20.2% of them received at least 1 dose of the PCV7 vaccine. Multivariate logistic regression models identified older age, having 1 sibling in a family, history of acute otitis media and household exposure to smoking as independent risk factors for pneumococcal carriage in the unvaccinated group, but not associated with pneumococcal carriage in the vaccinated group. The number of siblings ≥2 in a family, history of upper respiratory tract infection and child-care attendance were strong factors associated with pneumococcal carriage in children, regardless of vaccination. In vaccinated group, breast-feeding was associated with increased nonvaccine type pneumococcal carriage, mainly in children with upper respiratory tract infection.
  
  
  CONCLUSIONS
  PCV7 decreased the association between pneumococcal carriage and older age, 1 sibling in a family, history of acute otitis media and household exposure to smoking, but increased the association between pneumococcal carriage and breast-feeding.
authors.affiliation: Department of Pediatrics, Chang Gung Children's Hospital, Chang Gung Memorial Hospital, Chang Gung University, College of Medicine, Taoyuan, Taiwan.
authors.forename: Yu-Chia
authors.initials: YC
authors.lastname: Hsieh
authors.forename: Cheng-Hsun
authors.initials: CH
authors.lastname: Chiu
authors.forename: Kuang-Yi
authors.initials: KY
authors.lastname: Chang
authors.forename: Yhu-Chering
authors.initials: YC
authors.lastname: Huang
authors.forename: Chih-Jung
authors.initials: CJ
authors.lastname: Chen
authors.forename: Chen-Yen
authors.initials: CY
authors.lastname: Kuo
authors.forename: Po-Yen
authors.initials: PY
authors.lastname: Chen
authors.forename: Kao-Pin
authors.initials: KP
authors.lastname: Hwang
authors.forename: Tzou-Yien
authors.initials: TY
authors.lastname: Lin
mesh_terms: D000416:Alberta / Q000453:epidemiology; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009305:Nasopharynx / Q000382:microbiology; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D022242:Pneumococcal Vaccines / Q000008:administration & dosage*; D012307:Risk Factors; D013296:Streptococcus pneumoniae / Q000302:isolation & purification*; D011795:Surveys and Questionnaires
chemical_list: D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines