title: Rapid decrease of 7-valent conjugate vaccine coverage for invasive pneumococcal diseases in pediatric patients in Japan.
abstract: In Japan, the heptavalent pneumococcal conjugate vaccine (PCV7) has been introduced on a voluntary basis since February 2010, and official financial support for children under 5 years started in November 2010. The impact of PCV7 on invasive pneumococcal diseases (IPD) in children is unknown. There are 340 medical institutions that actively participated in our surveillance project throughout Japan. We collected 252 strains from patients with IPD in 2006 (pre-PCV7), 280 strains in 2010 (under 10% immunization achieved), and 128 strains in 2011 (50% to 60% immunization). Serotypes and penicillin-resistance genotypes (g) were compared between these years. Multilocus sequence typing was also carried out on these strains. Due to the official promotion, IPD significantly decreased in 2011 (p<0.001). In particular, meningitis and sepsis caused by vaccine type (VT) strains declined (p=0.033, p<0.001). In less than 2 years, among nonvaccine types (NVT), 15A and 22F increased in 2011 (p=0.015, p=0.015). Coverage by PCV7 decreased from 71.8% in 2006 to 51.6% in 2011. Sequence-type diversities accompanied by evolution to gPRSP occurred in both VT and NVT strains. Reduction of IPD caused by VT strains was accomplished, but a rapid increase of NVT raises concern about a future decrease in the efficacy of PCV7.
authors.affiliation: Laboratory of Molecular Epidemiology for Infectious Agents, Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Chiba
authors.forename: Miyuki
authors.initials: M
authors.lastname: Morozumi
authors.forename: Michi
authors.initials: M
authors.lastname: Shouji
authors.forename: Takeaki
authors.initials: T
authors.lastname: Wajima
authors.forename: Satoshi
authors.initials: S
authors.lastname: Iwata
authors.forename: Keisuke
authors.initials: K
authors.lastname: Sunakawa
authors.forename: Kimiko
authors.initials: K
authors.lastname: Ubukata
mesh_terms: D002648:Child; D002675:Child, Preschool; D004269:DNA, Bacterial / Q000145:classification / Q000235:genetics* / Q000276:immunology; D062665:Epidemiological Monitoring; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007223:Infant; D007564:Japan / Q000453:epidemiology; D008297:Male; D016920:Meningitis, Bacterial / Q000453:epidemiology / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D011008:Pneumococcal Infections / Q000453:epidemiology / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage* / Q000276:immunology; D018805:Sepsis / Q000453:epidemiology / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000276:immunology*; D014611:Vaccination
chemical_list: D004269:DNA, Bacterial; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines