2008-2009 season

2009-2010 season

Age group, Antigen

Immunization

No. of subject

Seroprotection rate,

% (95% CI)

Immunization

No. of subject

Seroprotection rate, % (95% CI)

School-aged children aged <9

After

vaccination^b

Post-season^c

Before

vaccination^a

After

vaccination^b

Post-season^c

Vaccine strain^d

Yes

48

66.7^*†

39.6^†

Yes

29

44.8^*

69.0^†

62.1

(52.1 - 79.2)

(25.0 - 54.2)

(27.6 - 62.1)

(51.7 - 86.2)

(44.8 - 75.9)

No

15

20^*

26.7

No

50

82^*

62.0^‡

46.0

(0 - 40)

(6.7 - 46.7)

(72.0 - 92.0)

(48.0 - 75.9)

(32.0 - 60.0)

Homologous

lineage strain^e

Yes

48

22.9

8.3

Yes

29

41.4

44.8

58.6

(12.5 - 35.4)

(2.1 - 16.7)

(24.1 - 58.6)

(27.6 - 65.4)

(41.4 - 75.9)

No

15

6.7

13.3

No

50

62.0

38.0

30.0

(0 - 20)

(0 - 33.3)

(48.0 - 74.0)

(24.0 - 52.0)

(18.0 - 44.0)

Heterologous lineage strain^f

Yes

48

19.4^*†

11.1^†

Yes

29

27.6

27.6^†

51.7

(8.3 - 33.3)

(2.8 - 22.2)

(10.3 - 44.8)

(10.3 - 44.8)

(34.5 - 69.0)

No

15

0^*

14.3

No

50

28.0

30.0^‡

26.0

(0 - 0)

(0 - 42.9)

(16.0 - 40.0)

(18.0 - 44.0)

(14.0 - 38.0)

School-aged children aged ≥9

Vaccine strain^d

Yes

36

72.2^*†

44.4^†

Yes

38

52.6

60.5

42.1

(56.0 - 86.1)

(27.8 - 58.3)

(34.2 - 68.4)

(44.7 - 73.7)

(23.7 - 57.9)

No

49

38.8^*

32.7

No

81

50.6

65.4

35.8

(26.5 - 51.0)

(21.1 - 46.2)

(38.3 - 59.3)

(54.3 - 74.1)

(25.9 - 45.7)

Homologous

lineage strain^e

Yes

36

52.8

33.3

Yes

38

34.2

60.5

31.6

(36.6 - 66.7)

(19.9 - 47.2)

(18.4 - 52.6)

(44.7 - 78.9)

(18.4 - 44.7)

No

49

24.5

16.3

No

81

43.2

49.4

24.7

(10.6 - 38.1)

(8.5 - 26.5)

(32.1 - 54.3)

(38.3 - 61.7)

(14.8 - 33.3)

Heterologous lineage strain^f

Yes

36

14.8^†

3.7^†

Yes

38

36.8

39.5

39.5

(3.7 - 33.3)

(0 - 14.2)

(23.7 - 50.0)

(23.7 - 60.5)

(23.7 - 55.3)

No

49

2.9

5.9

No

81

28.4

39.5

35.8

(0 - 8.8)

(0 - 17.1)

(19.8 - 38.3)

(29.6 - 50.6)

(25.9 - 45.7)