Table 4. Vaccine effectiveness estimates for trivalent inactivated vaccine based on influenza-positive and influenza-negative samples among cases and controls, Israel, influenza season 2015/16 (n = 1,658).
| Influenza type/subtype | Age | Cases (n = 785) |
Controls (n = 873) |
Crude VE | Adjusted VE | ||
|---|---|---|---|---|---|---|---|
| Vaccinated | Unvaccinated | Vaccinated | Unvaccinated | % (95% CI) | % (95%CI) | ||
| A and B | All | 111 | 674 | 131 | 742 | 6.7 (−22.6 to 29.0) | 8.8 (−25.1 to 33.5)a |
| 6 months–17 years | 55 | 310 | 44 | 406 | −63.7 (−149.9 to −7.2) | −25.0 (−98.0 to 21.0)b | |
| ≥ 18 years | 56 | 364 | 87 | 336 | 40.6 (14.2 to 58.8) | 39.1 (7.8 to 59.8)b | |
| A(H1N1)pdm09c | All | 38 | 305 | 131 | 742 | 29.4 (−3.7 to 52.0) | 32.3 (−4.3 to 56.1)a |
| 6 months–17 years | 17 | 112 | 44 | 406 | −40.1 (−154.6 to 22.9) | −8.1 (−104 to 42.7)b | |
| ≥ 18 years | 21 | 193 | 87 | 336 | 58.0 (30.1 to 74.7) | 56.5 (24.3 to 75.0)b | |
| Bc | All | 71 | 377 | 131 | 742 | −6.7 (−46.1 to 22.1) | −2.2 (−47.0 to 29.0)a |
| 6 months–17 years | 38 | 204 | 44 | 406 | −71.9 (−173.8 to −7.9) | −25.0 (−106.8 to 24.5)b | |
| ≥ 18 years | 33 | 173 | 87 | 336 | 26.3 (−14.5 to 52.6) | 26.5 (−20.6 to 55.2)b | |
a Adjusted for age group, sex, calendar week, underlying condition and time (days) from symptom onset to swab.
b Adjusted for sex, calendar week, underlying condition and time (days) from symptom onset to swab.
c The 11 samples positive for influenza A(H1N1)pdm09 and influenza B in the 2015/16 season are included in the analysis of influenza A(H1N1)pdm09 and influenza B.