title: Impact of pneumococcal conjugate vaccine in children on the serotypic epidemiology of adult invasive pneumococcal diseases in Taiwan.
abstract: BACKGROUND
  Invasive pneumococcal disease (IPD) causes significant morbidity and mortality, especially in children and older adults. Pneumococcal 7-valent and 13-valent conjugate vaccines (PCV7 and PCV13) were introduced in Taiwan in 2005 and 2011, respectively, for children. This study was conducted to evaluate the impact of PCV administered in children on adult IPD.
  
  
  METHODS
  From the logbooks of microbiology laboratories, we retrospectively retrieved Streptococcus pneumoniae isolates, collected from normally sterile sites in adult patients. One hundred and fifty-seven consecutive, nonduplicated isolates were collected from one hospital during 2001 and 2003 (pre-PCV period) and 150 isolates from three hospitals from July 2011 to June 2015 (post-PCV period). Serotypes were determined by Quellung test.
  
  
  RESULTS
  Among the 307 isolates, 31 serotypes/serogroups were identified. PCV7 serotypes, particularly types 14 (31.2%), 23F (19.7%) and 6B (12.7%) dominated in the pre-PCV period (78.3%) but significantly decreased in the post-PCV period (36%) (p < 0.01). PCV13 specific serotypes (PCV13-PCV7) significantly increased from 7% of the isolates in the pre-PCV period to 28.7% of the isolates in the post-PCV period (p < 0.001), particularly type 19A (from 0.6% to 10%) and 6A (from 0 to 6.7%). Serotype 15B also increased significantly from 0.6% to 6.7% (p < 0.01). Nonvaccine serotypes increased significantly in the post-PCV period (11.5% to 22.0%, p < 0.05), particularly type 15A (from 0 to 4.4%, p < 0.01).
  
  
  CONCLUSIONS
  Serotype distribution of adult IPD in Taiwan has evolved after the introduction of PCV in children, indicating an indirect impact in adults. Continuous surveillance after the PCV13 vaccination program in children is needed.
authors.affiliation: Department of Pediatrics, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan.
authors.forename: Hsiao-Chun
authors.initials: HC
authors.lastname: Chi
authors.affiliation: Department of Pediatrics, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Chang Gung University College of Medicine, Taoyuan, Taiwan.
authors.forename: Yu-Chia
authors.initials: YC
authors.lastname: Hsieh
authors.affiliation: Chang Gung University College of Medicine, Taoyuan, Taiwan; Department of Pediatrics, Chang Gung Memorial Hospital at Keelung, Keelung, Taiwan.
authors.forename: Ming-Han
authors.initials: MH
authors.lastname: Tsai
authors.affiliation: Chang Gung University College of Medicine, Taoyuan, Taiwan; Department of Internal Medicine, Chang Gung Memorial Hospital at Kaohsiung, Kaohsiung, Taiwan.
authors.forename: Chen-Hsiang
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Chang Gung University College of Medicine, Taoyuan, Taiwan; Department of Pediatrics, Chang Gung Memorial Hospital at Kaohsiung, Kaohsiung, Taiwan.
authors.forename: Kuang-Che
authors.initials: KC
authors.lastname: Kuo
authors.affiliation: Chang Gung University College of Medicine, Taoyuan, Taiwan; Department of Internal Medicine, Chang Gung Memorial Hospital at Linkou, Taiwan.
authors.forename: Ching-Tai
authors.initials: CT
authors.lastname: Huang
authors.affiliation: Department of Pediatrics, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Chang Gung University College of Medicine, Taoyuan, Taiwan. Electronic address: ychuang@cgmh.org.tw.
authors.forename: Yhu-Chering
authors.initials: YC
authors.lastname: Huang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine / Q000008:administration & dosage; D006761:Hospitals; D006801:Humans; D008297:Male; D008875:Middle Aged; D011008:Pneumococcal Infections / Q000453:epidemiology / Q000382:microbiology* / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage*; D012189:Retrospective Studies; D065288:Serogroup; D013296:Streptococcus pneumoniae / Q000145:classification / Q000302:isolation & purification; D013624:Taiwan / Q000453:epidemiology; D018074:Vaccines, Conjugate / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: C538862:13-valent pneumococcal vaccine; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate
keywords: Streptococcus pneumoniae; Taiwan; adult; invasive pneumococcal disease; serotype