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Volume 18, Number 11—November 2012

Dispatch

Pandemic Influenza Virus Surveillance, Izu-Oshima Island, Japan

Tomoko Inamasu1, Kouji Sudo, Shingo Kato, Hiroshi Deguchi, Manabu Ichikawa, Tadanori Shimizu, Tadami Maeda, Shuhei Fujimoto, Toru Takebayashi, and Tomoya Saito2Comments to Author 
Author affiliations: Author affiliations: Keio University Global Security Research Institute, Tokyo, Japan (T. Inamasu, K. Sudo, S. Kato, H. Deguchi, T. Saito); Keio University School of Medicine, Tokyo (K. Sudo, S. Kato, T. Takebayashi, T. Saito); Tokyo Institute of Technology, Kanagawa, Japan (H. Deguchi, M. Ichikawa); Oshima Medical Center, Tokyo (T. Shimizu); Maeda Internal Medicine Clinic, Tokyo (T. Maeda); Tokai University School of Medicine, Kanagawa (S. Fujimoto)

Main Article

Table 2

Incidence of major influenza virus subtypes endemic to Izu-Oshima Island, Japan, by influenza season

Age, y* Incidence of influenza cases among Izu-Oshima residents, no. (%)
2008–09
2009–10
2010–11
Cumulative incidence of A/H1¶
No.† Influenza virus type
No.† Influenza virus type A/H1§ No.† Influenza virus type
A‡ B A/H1§ A/H3 B
0–4 326 65 (19.9) 11 (3.4) 323 36 (11.1) 316 20 (6.3) 21 (6.6) 16 (5.1) 41 (13.0)
5–9 366 98 (26.8) 51 (13.9) 367 105 (28.6) 349 39 (11.2) 6 (1.7) 91 (26.1) 137 (39.3)
10–14 316 53 (16.8) 44 (13.9) 316 97 (30.7) 332 26 (7.8) 3 (0.9) 48 (14.5) 143 (43.1)
15–19 475 10 (2.1) 4 (0.8) 480 91 (19.0) 475 24 (5.1) 0 6 (1.3) 129 (27.2)
20–29 541 19 (3.5) 3 (0.6) 492 25 (5.1) 486 12 (2.5) 2 (0.4) 2 (0.4) 39 (8.0)
30–39 987 56 (5.7) 1 (0.1) 991 39 (3.9) 951 22 (2.3) 9 (0.9) 5 (0.5) 62 (6.5)
40–49 977 27 (2.8) 2 (0.2) 971 21 (2.2) 996 18 (1.8) 7 (0.7) 5 (0.5) 42 (4.2)
50–59 1,396 15 (1.1) 1 (0.1) 1,283 14 (1.1) 1,179 10 (1.8) 5 (4.2) 4 (0.3) 24 (2.0)
>60
3,472
12 (0.3)
3 (0.1)

3,540
8 (0.2)

3,568
2 (0.1)
5 (0.1)
2 (0.1)
11 (0.3)
Total 8,856 355 (4.0) 120 (1.4) 8,763 436 (5.0) 8,652 173 (2.0) 58 (0.7) 179 (2.1) 628 (7.3)

*Age during January 2009 (for 2008–09), 2010 (for 2009–10), and 2011 (for 2010–11).
†Population recorded in the Resident Registry in January 2009 (for 2008–09), 2010 (for 2009–10), and 2011 (for 2010–11).
‡Influenza A (unspecified). The number of second diagnoses in the season was excluded.
§Influenza A(H1N1)pdm09.
¶The sum of influenza A(H1N1)pdm09 cases among residents in Izu-Oshima during the study divided by the population during January 2011.

Main Article

1Current affiliation: Juntendo University Graduate School of Medicine, Tokyo.

2Current affiliation: Tokyo Institute of Technology, Yokohama, Japan.

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