Table 2.
Confounder-adjusted VE estimates and cumulative confounder-adjusted VE estimates (adjusted for symptom onset, sex, age and chronic conditions) by time since last dose in SARI patients who had received two doses of AZD1222 and were hospitalised between June 1st, 2021, and September 5th, 2022.
| Time since last dose of AZD1222 | Exposure | Test-negative controls, n | Test-positive cases, n | VE, % (95% CI) |
|---|---|---|---|---|
| Time period | ||||
| 2 to ≤8 weeks | Vaccinated | 4 | 2 | 93.8 (48.6–99.3) |
| Unvaccinated | 140 | 501 | ||
| >8 to ≤16 weeks | Vaccinated | 20 | 8 | 79.4 (41.9–92.7) |
| Unvaccinated | 140 | 501 | ||
| >16 to ≤24 weeks | Vaccinated | 25 | 38 | 67.2 (30.8–84.4) |
| Unvaccinated | 140 | 501 | ||
| >24 to ≤32 weeks | Vaccinated | 5 | 10 | 56.6 (−52.6 to 87.7) |
| Unvaccinated | 140 | 501 | ||
| >32 weeks | Vaccinated | 6 | 2 | 76.1 (−39.7 to 95.9) |
| Unvaccinated | 140 | 501 | ||
| Cumulative time | ||||
| ≤8 weeks | Vaccinated | 4 | 2 | 93.8 (48.6–99.3) |
| Unvaccinated | 140 | 501 | ||
| ≤16 weeks | Vaccinated | 24 | 10 | 84.0 (59.1–93.8) |
| Unvaccinated | 140 | 501 | ||
| ≤24 weeks | Vaccinated | 49 | 48 | 74.5 (53.2–86.1) |
| Unvaccinated | 140 | 501 | ||
| ≤32 weeks | Vaccinated | 54 | 58 | 71.3 (49.6–83.6) |
| Unvaccinated | 140 | 501 | ||
| All (full analysis period)a | Vaccinated | 60 | 60 | 72.8 (53.4–84.1) |
| Unvaccinated | 140 | 501 |
CI = confidence interval. VE = vaccine effectiveness. SARI = severe acute respiratory infection.
a
Estimated VE in all individuals included during the 15-month analysis period from June 2021 to September 2022, regardless of time since vaccination.