Table 4.
Relative efficacy of LAIV versus TIV age and strain (studies 3 and 4)
| Study | Age (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 | ||||||
| 3 | 6–35 months (952) | 31 (−30 to 64) | 0 | 1·1 | 100 (1–100) | 2·6 | 1·8 | −47 (−309 to 44) | 1·2 | 2·7 | 55 (−30 to 86) |
| 3–6 years (1133) | 70 (38–87) | 0 | 0·9 | 100 (−16 to 100) | 0·9 | 0·7 | −33 (−568 to 72) | 1·1 | 4·5 | 76 (39–92) | |
| 4** | 6–11 years (1376) | 31 (−8 to 57) | 0 | 0·6 | 100 (−62 to 100) | 1·5 | 1·0 | −53 (−373 to 48) | 3·8 | 5·9 | 36 (−7 to 63) |
| 12–17 years (835) | 30 (−43 to 66) | 0 | 0·5 | 100 (−369 to 100) | 1·6 | 1·5 | −3 (−270 to 70) | 2·3 | 3·3 | 32 (−67 to 73) | |
LAIV, live attenuated influenza vaccine; TIV, trivalent inactivated influenza vaccine.
*Regardless of antigenic match to vaccine.
**Conducted in children with stable, medically treated asthma, a population for whom there is a warning/precaution against the use of LAIV.