Article in Japanese

Trend of invasive pneumococcal disease before and after the introduction of pneumococcal conjugate vaccine in Hiroshima city

Yumi B. TAMURA^1,2), Keita MATSUBARA¹⁾, Chiharu MATSUBARA¹⁾, Tomoki SATOU¹⁾, Hiroyuki SHIMOZONO¹⁾

Objective: The incidence of invasive pneumococcal disease (IPD) has decreased dramatically in Japan, due to the introduction of pneumococcal conjugate vaccine (PCV). This study conducted an investigation to verify the effect of PCV in Hiroshima city medical district by considering cases of IPD and their serotypes in this hospital. Methods: A retrospective study was conducted to analyze the age of the patients, serotypes of the isolate and penicillin sensitivity of 50 strains of Streptococcus pneumoniae; isolated from IPD cases in this hospital from 2007 to 2015. Results: Seven cases of bacterial meningitis and 43 of bacteremia were identified. Twenty-five, 18 and 7 cases were from a period before the introduction of PCV (2007-2009), when PCV was introduced (2010-2012), and after the introduction of PCV (2013-2015), respectively. Isolated serotypes were mainly vaccine serotypes before the introduction of PCV, but vaccine serotypes decreased dramatically after the introduction of PCV. On the other hand, the non-vaccine serotype IPD showed a relative increase. Drug resistant isolates have decreased since 2013, which also indicates the effect of PCV. Conclusion: This study confirmed the decrease of IPD incidence and relative increase of non-vaccine serotype IPD in Hiroshima city medical district, and a similar phenomenon was noted in various districts in Japan.

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1) Department of Pediatrics, Miyoshi Central Hospital
2) Department of Pediatrics, Hiroshima City Funairi Citizens Hospital

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Received	February 27, 2017
Accepted	May 18, 2017

29 (3)：241─248,2017