Table 3. Vaccine effectiveness estimates for trivalent inactivated vaccine based on influenza-positive and influenza-negative samples among cases and controls, Israel, influenza season 2014/15 (n =1,005).
| Influenza type/subtype | Age | Cases (n =307) |
Controls (n =698) |
Crude VE | Adjusted VE | ||
|---|---|---|---|---|---|---|---|
| Vaccinated | Unvaccinated | Vaccinated | Unvaccinated | % (95% CI) | % (95%CI) | ||
| A and B | All | 59 | 248 | 121 | 577 | −13.4 (−60.2 to 19.7) | −4.8 (−54.8 to 29.0)a |
| 6 months–17 years | 24 | 151 | 68 | 345 | 19.4 (−33.4 to 51.2) | 30.5 (−18.3 to 59.1)b | |
| ≥18 years | 35 | 97 | 53 | 232 | −58.0 (−157.4 to 3.1) | −53.7 (−166.8 to 11.4)b | |
| A(H3N2) | All | 53 | 204 | 121 | 577 | −23.9 (−77.6 to 13.6) | −15.8 (−72.8 to 22.4)a |
| 6 months–17 years | 24 | 133 | 68 | 345 | 8.4 (−51.9 to 44.8) | 22.7 (−31.7 to 54.6)b | |
| ≥ 18 years | 29 | 71 | 53 | 232 | −78.8 (−202.3 to −5.8) | −75.7 (−216.3 to 2.4)b | |
VE: vaccine effectiveness.
a Adjusted for age group, sex, calendar week and time (days) from symptom onset to swab.
b Adjusted for sex, calendar week and time (days) from symptom onset to swab.