Table 2.
Hazard ratio (HR) and 95% confidence interval (95 %CI) between vaccination and the risk of hospitalization for COVID-19 and the related risk reduction by windows of follow-up. Adjustment for age, sex, region, type of residence by matching and for other variables of Table 1 (including comorbidities) using inverse probability of treatment weighting.
| Population | Unvaccinated | Vaccinated |
|---|---|---|
| Follow-up after the 1st dose | ||
| Number of events/at-risk population | 6,580/2,631,108 | 1,463/1,422,461 |
| Median follow-up and interquartile range (days) | 38 [17–54] | 40 [19–55] |
| HR (95 %CI) | 1 | 0.40 (0.38–0.42) |
| Risk reduction (95 %CI) | 60% (58%–62%) | |
| Follow-up from 1st dose to day 13 | ||
| Number of events/at-risk population | 2,795/2,631,108 | 685/1,422,461 |
| Median follow-up and interquartile range (days) | 14 [14–14] | 14 [14–14] |
| HR (95 %CI) | 1 | 0.45 (0.41–0.49) |
| Risk reduction (95 %CI) | 55% (51% − 59%) | |
| Follow-up from day 14 after the 1st dose to the 2nd dose | ||
| Number of events/at-risk population | 1,616/2,091,749 | 594/1,145,854 |
| Median follow-up and interquartile range (days) | 12 [7–13] | 12 [7–13] |
| HR (95 %CI) | 1 | 0.66 (0.60–0.72) |
| Risk reduction (95 %CI) | 34% (28%–40%) | |
| Follow-up after the 2nd dose | ||
| Number of events/at-risk population | 2,142/1,692,867 | 175/935,987 |
| Median follow-up and interquartile range (days) | 22 [12–34] | 22 [12–34] |
| HR (95 %CI) | 1 | 0.14 (0.12–0.17) |
| Risk reduction (95 %CI) | 86% (83%–88%) | |
| Follow-up from day 7 after the 2nd dose | ||
| Number of events/at-risk population | 1,406/1,511,628 | 113/840,546 |
| Median of follow-up and interquartile range (days) | 17 [9–28] | 18 [9–28] |
| HR (95 %CI) | 1 | 0.14 (0.11–0.17) |
| Risk reduction (95 %CI) | 86% (83%–89%) | |