title: The incidence of pediatric invasive Haemophilus influenzae and pneumococcal disease in Chiba prefecture, Japan before and after the introduction of conjugate vaccines.
abstract: The Haemophilus influenzae type b (Hib) vaccine and the heptavalent pneumococcal conjugate vaccine (PCV7) were introduced in Japan in 2008 and 2010, respectively. In 2011, immunization with these two vaccines was encouraged throughout Japan through a governmental program. Children treated in Chiba prefecture for culture-proven invasive H. influenzae disease (IHiD) and invasive Streptococcus pneumoniae disease (IPD) were identified in a prefectural surveillance study from 2008 to 2013. The incidence rate ratio (IRR) and its confidence interval (CI) were calculated to compare the 3 years before and after governmental financial support for vaccination. The average number of IHiD and IPD cases among children <5 years of age in 2011-2013 decreased 84% (IRR: 0.16, 95% CI: 0.09-0.26, p<0.0001) and 51% (IRR: 0.49, 95% CI: 0.37-0.63, p<0.0001) compared with those occurring in 2008-2010. The most common non-PCV7 serotype encountered in 2011 and 2013 was 19A. After governmental subsidization of Hib and PCV7 vaccination, IHiD and IPD decreased in Chiba prefecture, Japan. Continuous surveillance is necessary to determine the effectiveness of these two vaccines and for detection of emerging invasive serotypes.
authors.affiliation: Division of Control and Treatment of Infectious Diseases, Chiba University Hospital, Chiba, Japan. Electronic address: ishiwada@faculty.chiba-u.jp.
authors.forename: Naruhiko
authors.initials: N
authors.lastname: Ishiwada
authors.affiliation: Department of Pediatrics, Chiba University Graduate School of Medicine, Chiba, Japan.
authors.forename: Haruka
authors.initials: H
authors.lastname: Hishiki
authors.affiliation: Department of Pediatrics, Chiba University Graduate School of Medicine, Chiba, Japan.
authors.forename: Koo
authors.initials: K
authors.lastname: Nagasawa
authors.affiliation: Department of Pediatrics, Chiba University Graduate School of Medicine, Chiba, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Naito
authors.affiliation: Clinical Research Center, Chiba University Hospital, Chiba, Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Sato
authors.affiliation: Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Bin
authors.initials: B
authors.lastname: Chang
authors.affiliation: Department of Bacteriology II, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Sasaki
authors.affiliation: Department of Bacteriology II, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Kouji
authors.initials: K
authors.lastname: Kimura
authors.affiliation: Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ohnishi
authors.affiliation: Department of Bacteriology II, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Keigo
authors.initials: K
authors.lastname: Shibayama
mesh_terms: D016667:Bacterial Capsules; D002675:Child, Preschool; D005260:Female; D006192:Haemophilus Infections / Q000453:epidemiology* / Q000517:prevention & control; D018073:Haemophilus Vaccines / Q000627:therapeutic use*; D006193:Haemophilus influenzae; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D017589:Immunization Programs; D015994:Incidence; D007223:Infant; D007564:Japan / Q000453:epidemiology; D008297:Male; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000517:prevention & control; D022242:Pneumococcal Vaccines / Q000627:therapeutic use*; D018571:Sentinel Surveillance; D018074:Vaccines, Conjugate
chemical_list: D018073:Haemophilus Vaccines; C044237:Haemophilus influenzae type b polysaccharide vaccine; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate
keywords: Children; Haemophilus influenzae; Invasive disease; Japan; Streptococcus pneumoniae