Table 3. Estimates of the effectiveness of one dose of varicella vaccine according to time since vaccination.
| Varicella vaccine status | Cases/ controls | Crude vaccine effectiveness (95% CI) * |
Adjusted vaccine effectiveness (95% CI) # |
p-value |
|---|---|---|---|---|
| Unvaccinated | 48/257 | - | - | |
| < 12 mo after vaccination | 1/30 | 89% (4%; 100%) | 93% (34%; 100%) | 0.011 |
| 12–35 mo after vaccination | 1/47 | 93% (51%; 100%) | 95% (62%; 100%) | < 0.001 |
| ≥ 36 mo after vaccination | 3/35 | 64% (-42%; 94%) | 61% (-64%; 94%) | 0.271 |
*Result of the unadjusted conditional logistic regression model. # Result of the exact conditional logistic regression adjusted for migrant parents and visits to the pediatrician in the previous 12 mo.