Table 4.
Outcomes by vaccination history. Comparison of log-transformed HI titre levels at baseline and one month, 4-fold conversion and seroprotection rates for antibodies, and vaccine reaction and influenza-like symptom reporting for prior year’s vaccination status. Values are expressed as means ± standard deviation or as percentages (n); p values are for chi-square or t tests.
| Prior year | ||||
|---|---|---|---|---|
| Outcomes | Vaccinated (n = 36) | Not vaccinated (n = 11) | p value | |
| A/California/7/2009 | Baseline | 0.98 ± 0.612 | 0.00 ± 0.000 | <.001 |
| 1 month | 1.65 ± 0.665 | 1.84 ± 0.617 | .461 | |
| 4-fold at 1 month | 25.7% (9) | 55.6% (5) | .086 | |
| seroprotection at 1 month | 65.7% (23) | 66.7% (6) | .957 | |
| A/Perth/16/2009 | Baseline | 1.20 ± 0.699 | 0.53 ± 0.856 | .020 |
| 1 month | 2.05 ± 0.529 | 1.84 ± 0.446 | .280 | |
| 4-fold at 1 month | 52.8% (19) | 66.7% (6) | .453 | |
| seroprotection at 1 month | 94.4% (34) | 88.9% (8) | .550 | |
| B/Brisbane/60/2008 | Baseline | 1.35 ± 0.445 | 0.62 ± 0.602 | .007 |
| 1 month | 1.79 ± 0.466 | 1.67 ± 0.598 | .508 | |
| 4-fold at 1 month | 5.6% (2) | 33.3% (3) | .018 | |
| seroprotection at 1 month | 86.1% (31) | 55.6% (5) | .040 | |
| Illness within 48 h | 8.3% (3) | 10.0% (1) | .869 | |
| Symptom frequency | 23.7 ± 21.67% | 22.9 ± 19.26% | .925 | |