Age (wk)

IVV

100 µg VR^*

100 µg VR-HA^*

500 µg VR-HA

500 µg VR-HA^*

1^st vaccination

6

3/3 (3.8 ± 1.3)^**

0/3

0/3

0/3

0/3

2^nd vaccination

9

3/3 (6.0 ± 1.2)^A

0/3

0/3

0/3

0/3

3^rd vaccination

15

0/3^A

1/3 (0.7 ± 1.2)^A

0/3

1/3^***A

Post virus challenge

22

3/3 (9.6 ± 1.7)^B

3/3 (7.7 ± 4.0)^B

3/3 (6.7 ± 0.6)^B

3/3 (8.7 ± 4.7)^B