title: Invasive pneumococcal disease among adults in Japan, April 2013 to March 2015: disease characteristics and serotype distribution.
abstract: In Japan, the clinical characteristics and recent serotype distribution among adult patients of invasive pneumococcal disease (IPD) have not been fully investigated since the introduction of the pneumococcal conjugate vaccine (PCV) in children. From November 2010, PCV7 was encouraged by an official program, funded by government, subsequently included in the routine schedule in April 2013, and replaced with a PCV13 in November 2013.
  
  
  
  Between April 2013 and March 2015, patients with IPD older than 15 years were evaluated based on the enhanced national surveillance in ten prefectures of Japan. The serotype distribution of the isolates was analyzed in these patients.
  
  
  
  The analysis included 291 patients: 107 patients (37%) were female and the median age was 70 years. Of 281 patients with available data, 202 (72%) had underlying diseases, including 107 patients (38%) with immunocompromised status. The case fatality proportion for all case was 20%. In subgroup analysis, the case fatality proportion (29%) in immunocompromised patients was much higher than that (0-16%) in each age group of nonimmunocompromised patients (15-39 years, 40-64 years, and ≥ 65 years). While the proportion of bacteremia without any focus (27%) was higher than that (8-10%) in nonimmunocompromised patients, the proportions of vaccine types (PCV13, 32%; PPSV23, 51%) of the causative isolates were lower than those in each age group of nonimmunocompromised patients. Among 291 isolates, the most frequent serotypes were 3 (17%), 19A (13%), and 22F (10%). Twelve percent of the isolates were PCV7 serotypes, 46% were PCV13 serotypes, and 66% were PPSV23 serotypes.
  
  
  
  The majority of adult patients of IPD had underlying diseases, including immunocompromised conditions. A low proportion (12%) of PCV7-type IPD was observed in this population where PCV7 for children had been included in the routine immunization schedule.
authors.affiliation: Field Epidemiology Training Program, National Institute of Infectious Diseases, Tokyo, Japan.|Department of Epidemiology for Infectious Diseases, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Munehisa
authors.initials: M
authors.lastname: Fukusumi
authors.affiliation: Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Bin
authors.initials: B
authors.lastname: Chang
authors.affiliation: Division of Infection Control and Prevention, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Tanabe
authors.affiliation: Department of Infection Control and Laboratory Diagnostics, Internal Medicine, Tohoku University Graduate School of Medicine, Miyagi, Japan.
authors.forename: Kengo
authors.initials: K
authors.lastname: Oshima
authors.affiliation: Department of Medicine, National Hospital Organization, Mie Hospital, Mie, Japan.
authors.forename: Takaya
authors.initials: T
authors.lastname: Maruyama
authors.affiliation: Department of Infection Control and Prevention, Kurume University School of Medicine, Fukuoka, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watanabe
authors.affiliation: Department of Respiratory Medicine and Allergology, Sapporo Medical University School of Medicine, Hokkaido, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Kuronuma
authors.affiliation: Center for Infectious Diseases, Nara Medical University, Nara, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Kasahara
authors.affiliation: Department of Respiratory Medicine, Yamagata Saisei Hospital, Yamagata, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Takeda
authors.affiliation: Department of Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
authors.forename: Junichiro
authors.initials: J
authors.lastname: Nishi
authors.affiliation: Department of Infectious Diseases, Respiratory and Digestive Medicine, Faculty of Medicine, University of the Ryukyus, Okinawa, Japan.
authors.forename: Jiro
authors.initials: J
authors.lastname: Fujita
authors.affiliation: Department of Hematology and Respiratory Medicine, Kochi Medical School, Kochi University, Kochi, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kubota
authors.affiliation: Infectious Diseases Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Tomimasa
authors.initials: T
authors.lastname: Sunagawa
authors.affiliation: Infectious Diseases Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Tamano
authors.initials: T
authors.lastname: Matsui
authors.affiliation: Infectious Diseases Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan. oishik@nih.go.jp.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Oishi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000382:microbiology* / Q000517:prevention & control; D022242:Pneumococcal Vaccines / Q000627:therapeutic use; D065288:Serogroup; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification; D018074:Vaccines, Conjugate / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate
keywords: Indirect effect; Invasive pneumococcal disease; Streptococcus pneumoniae; Surveillance