Protective effects of influenza A (H1N1) pandemic 2009 vaccination against the onset of influenza-like illness and asthma exacerbation in Japanese children

• Published in: The Journal of asthma 2014-10, Vol.51 (8), p.825-831
• Main Authors: Yokouchi, Yukako, Katsumori, Hiroshi, Shirakawa, Seigo, Fujiwara, Maya, Kashima, Kyoko, Kozawa, Ryo, Koike, Yuji
• Format: Article
• Language: English
• Subjects: Asthma - complications; Asthmatic; Child; Cross-Sectional Studies; Disease Progression; Female; high-risk group; Humans; Influenza A Virus, H1N1 Subtype; Influenza Vaccines; Influenza, Human - complications; Influenza, Human - epidemiology; Influenza, Human - prevention & control; Japan - epidemiology; Male; pandemic; Pandemics - prevention & control; pediatrics; Surveys and Questionnaires; vaccine
• ISSN: 0277-0903; 1532-4303
• DOI: 10.3109/02770903.2014.915567

Abstract Background: Vaccination against influenza A(H1N1)pdm09 in Japan started in October 2009. Children with asthma are considered as a high-risk group and are recommended to preferentially receive the vaccine. Objective: To identify the clinical effects of vaccination in Japanese children with and without asthma. Methods: We conducted a cross-sectional, questionnaire-based survey to compare vaccination rates, vaccine effectiveness against physician-diagnosed influenza A infection (PDIA), and consecutive asthma exacerbations between children with and without asthma. Results: Of the 460 children included in this study, those with asthma had higher vaccination rates (46.5%, 67/144) than those without asthma (30.4%, 96/316). Influenza A infections were diagnosed in 28 of 163 vaccinated children (17.2%) compared to 164 of 297 unvaccinated children (55.2%, p