title: Nationwide population-based surveillance of invasive pneumococcal disease in Japanese children: Effects of the seven-valent pneumococcal conjugate vaccine.
abstract: BACKGROUND
  In Japan, the seven-valent pneumococcal conjugate vaccine (PCV7) was introduced in 2010. PCV13 has replaced PCV7 since November 2013.
  
  
  METHODS
  The effectiveness of PCV7 in protecting against invasive pneumococcal disease (IPD) in children aged <5 years was evaluated in a nationwide active population-based surveillance of IPD in 2008-2013 in 10 prefectures in Japan.
  
  
  RESULTS
  1181 cases were identified; 711 pneumococcal strains were analyzed for serotyping and antimicrobial resistance. Compared with the baseline IPD incidence (25.0 per 100,000), a 98% decline in IPD caused by PCV7 serotypes was found after the introduction of PCV7. This was partially offset by an increased incidence of IPD caused by PCV13 minus PCV7 and non-PCV13 serotypes, resulting in a 57% decline in overall IPD incidence. Absolute increases in the incidence rates of IPD caused by PCV13 minus PCV7 and non-PCV13 serotypes were 2.1 and 2.8 per 100,000 during the study period, respectively. The proportion of meropenem-nonsusceptible strains, especially with serotypes 19A and 15A, increased significantly after PCV7 introduction.
  
  
  CONCLUSIONS
  Our data confirmed a 98% decline in IPD incidence caused by PCV7 serotypes in children aged <5 years and serotype replacement after PCV7 introduction. This shows the importance of continuing surveillance of serotypes responsible for IPD and their antimicrobial resistance in Japan.
authors.affiliation: Infectious Disease Center and Department of Clinical Research, National Hospital Organization Mie Hospital, Mie, Japan. Electronic address: sugas@mie-m.hosp.go.jp.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Suga
authors.affiliation: National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Bin
authors.initials: B
authors.lastname: Chang
authors.affiliation: Infectious Disease Center and Department of Clinical Research, National Hospital Organization Mie Hospital, Mie, Japan.
authors.forename: Kazutoyo
authors.initials: K
authors.lastname: Asada
authors.affiliation: Okinawa Prefectural Nanbu Medical Center & Children's Medical Center, Okinawa, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Akeda
authors.affiliation: Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
authors.forename: Junichiro
authors.initials: J
authors.lastname: Nishi
authors.affiliation: Section of Pediatrics, Department of Medicine, Division of Oral and Medical Management, Fukuoka Dental College, Fukuoka, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Okada
authors.affiliation: Kochi University, Kochi, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Wakiguchi
authors.affiliation: Department of Pediatrics, Kochi Prefectural Hata-Kenmin Hospital, Kochi, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Maeda
authors.affiliation: Okayama University Graduate School of Health Sciences, Okayama, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Oda
authors.affiliation: Department of Infectious Diseases, Medical Mycology Research Center, Chiba University, Chiba, Japan.
authors.forename: Naruhiko
authors.initials: N
authors.lastname: Ishiwada
authors.affiliation: Department of Pediatrics, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Saitoh
authors.affiliation: Department of Pediatrics, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Oishi
authors.affiliation: Department of Pediatrics, Fukushima Medical University School of Medicine, Fukushima, Japan.
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Hosoya
authors.affiliation: Sapporo City University School of Nursing, Hokkaido, Japan.
authors.forename: Takehiro
authors.initials: T
authors.lastname: Togashi
authors.affiliation: National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Oishi
authors.affiliation: Infectious Disease Center and Department of Clinical Research, National Hospital Organization Mie Hospital, Mie, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Ihara
mesh_terms: D000293:Adolescent; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine / Q000276:immunology*; D006801:Humans; D007223:Infant; D007564:Japan / Q000453:epidemiology; D008297:Male; D000077731:Meropenem; D008826:Microbial Sensitivity Tests; D011008:Pneumococcal Infections / Q000208:ethnology / Q000382:microbiology* / Q000401:mortality / Q000517:prevention & control*; D011159:Population Surveillance; D011446:Prospective Studies; D065288:Serogroup; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000187:drug effects* / Q000472:pathogenicity; D013845:Thienamycins / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D013845:Thienamycins; D000077731:Meropenem
keywords: Children; Invasive pneumococcal disease; Japan; Meropenem; Serotype replacement; Seven-valent pneumococcal conjugate vaccine