Table 5.
VE against any influenza stratified by prior vaccination.
| Current Vaccination Dose | n (%) | Crude VE (95% CI) |
Adjusted VE (95% CI) a |
Adjusted VE (95% CI) b |
|
|---|---|---|---|---|---|
| Unvaccinated in prior season | Cases (n = 544) | Controls (n = 762) | |||
| 0 | 458 (84) | 493 (65) | Reference | Reference | Reference |
| 1 | 25 (5) | 45 (6) | 40% (1% to 64%) | 44% (−22% to 74%) | 40% (−35% to 73%) |
| 2 | 61 (11) | 224 (29) | 71% (60% to 79%) | 64% (42% to 78%) | 60% (34% to 75%) |
| Vaccinated in prior season | Cases (n = 255) | Controls (n = 434) | |||
| 0 | 55 (22) | 68 (16) | Reference | Reference | Reference |
| 1 | 52 (20) | 94 (22) | 32% (−12% to 58%) | 76% (31% to 91%) | 80% (36% to 94%) |
| 2 | 148 (58) | 272 (62) | 33% (−1% to 55%) | 69% (29% to 87%) | 75% (36% to 90%) |
VE; vaccine effectiveness. CI; confidence interval. a Stratified variables: enrolment season, clinic, week, and age (1-year interval). b Stratified variables: enrolment season, clinic, week, and age (1-year interval). Adjusted variables: sex, sibling, nursery school, interval between illness onset and enrolment (0–2/≥3 days), medical comorbidities, number of outpatient visits (0–4/5–9/≥10) in the prior season, influenza diagnosis in the prior season, and influenza vaccination until the season before prior season (0/≥1).