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)
山下 昭美 大阪市立大学, 大学院・医学研究科, 助手 (50094496)
|Budget Amount *help
¥7,900,000 (Direct Cost : ¥7,900,000)
Fiscal Year 2004 : ¥1,400,000 (Direct Cost : ¥1,400,000)
Fiscal Year 2003 : ¥2,600,000 (Direct Cost : ¥2,600,000)
Fiscal Year 2002 : ¥3,900,000 (Direct Cost : ¥3,900,000)
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.
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.
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.