| Co-Investigator(Kenkyū-buntansha) |
TANAKA Takashi OSAKA CITY UNIVERSITY, Faculty of Medicine, Associate professor, 大学院・医学研究科, 助教授 (30227144)
OKADA Mitsuko OSAKA CITY UNIVERSITY, Faculty of Medicine, Research Associate, 大学院・医学研究科, 助手 (20347496)
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| Research Abstract |
【Immunology】
1)Influenza vaccine in the 2002/03 season induced fairly high level of HI titer for A/New Caledonia (H1) and A/Panama (H3), but not for B/Shangdong.
2)The preseason HI titer against A/Panama (H3) was negatively associated with the risk of infection.
3)As compared to HI titer less than 1:40 in the preseason, the risk of contracting influenza-like illness(ILI) decreased to 1/3 or less at 1:40 to 1:160, and to about 1/10 at 1:320 or higher.
4)A/Panama (H3) included in the 2002/03 vaccine induced cross-reactive immunity against A/Wyoming (H3), drifted strain circulating in the season.
【Clinical epidemiology】
5)The ILI defined as "fever≧38.0℃" showed 65〜70% in sensitivity and 90〜95% in specificity, when compared with the infection, i.e., HI titer rise≧4-fold between pre- and post-season sera, as a gold standard.
6)Multivariate adjusted odds ratio (OR) of vaccination for ILI was 0.70 (95%CI: 0.46-1.08, P=0.108) in Iwate, and 0.93 (0.63-1.38, P=0.724) in Fukuoka.
【Meta-analysis】
7)Meta-analyses were performed in pooling the data from 7 districts in 3 seasons which included not only our original data but also previous reports. The obtained summary OR showed quite a stable value, 0.76 (0.69-0.83, P=0.000).
8)In the computation by one-year age class, the summary ORs in 5 classes at one year or older of age were all less than unity ranging 0.64〜0.88, and the summary ORs in 4 classes were statistically or marginally significant. On the other hand, the summary OR at the age class less than one was 1.30 (0.82-2.05, P=0.267),
9)Influenza vaccine reduced the risk of ILI to about 3/4 among young children, although effectiveness is still unclear among infants less than one year of age.
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