Table 3.
Relative efficacy of LAIV versus TIV by age and strain (study 2)
| Age, months (n) | All strains* Relative efficacy, % (95% CI) | H1N1* | H3N2* | B* | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Attack rate, % | Relative efficacy, % (95% CI) | Attack rate, % | Relative efficacy, % (95% CI) | Attack rate, % | Relative efficacy, % (95% CI) | |||||
| LAIV | TIV | LAIV | TIV | LAIV | TIV | |||||
| 6–23 (3686) | 56 (40–68) | 0·1 | 0·3 | 67 (−56 to 95) | 0·7 | 4·1 | 83 (70–91) | 2·3 | 2·7 | 15 (−29 to 43) |
| 24–35 (2612) | 57 (40–69) | 0·1 | 0·3 | 78 (−79 to 99) | 1·0 | 5·6 | 82 (68–90) | 2·8 | 3·0 | 10 (−42 to 43) |
| 36–47 (846) | 42 (5–66) | 0 | 2·3 | 100 (63–100) | 1·7 | 3·4 | 48 (−29 to 81) | 4·1 | 4·8 | 12 (−69 to 55) |
| 48–59 (708) | 56 (25–75) | 0 | 2·0 | 100 (47–100) | 1·1 | 4·0 | 76 (22–95) | 5·0 | 7·5 | 25 (−37 to 60) |
LAIV, live attenuated influenza vaccine; TIV, trivalent inactivated influenza vaccine.
*Regardless of antigenic match to vaccine.