Table 3.
Association between age at vaccine completion and other features of the study cohort and the odds of post-vaccine SARS-CoV-2 infection, left panel, and severe COVID-19 illness, right panel (please see text, Question 8).
| Post-Vaccine SARS-CoV-2 Infection | Post-Vaccine Severe COVID-19 Illness | |||||||
|---|---|---|---|---|---|---|---|---|
| Cases | Controls | OR | (95% CI) | Cases | Controls | OR | (95% CI) | |
| Age category | ||||||||
| <40 yrs | 3083 (21.2%) | 2805 (15.6%) | 1.00 | (ref.) | 84 (2.8%) | 2581 (8.5%) | 1.00 | (ref.) |
| 40 to 59 yrs | 7247 (40.3%) | 6903 (38.4%) | 0.76 | (0.70 to 0.83) | 384 (12.7%) | 6204 (20.5%) | 1.60 | (1.14 to 2.25) |
| 60 to 79 yrs | 3892 (21.7%) | 4926 (27.4%) | 0.46 | (0.42 to 0.51) | 660 (21.8%) | 6416 (21.2%) | 2.48 | (1.76 to 3.50) |
| ≥80 yrs | 3024 (16.8%) | 3332 (18.5%) | 0.51 | (0.44 to 0.59) | 1895 (62.7%) | 15,029 (49.7%) | 6.99 | (4.89 to 9.99) |
| Sex | ||||||||
| Female | 10,023 (55.7%) | 10,164 (56.5%) | 1.00 | (ref.) | 1505 (49.8%) | 17,299 (57.2%) | 1.00 | (ref.) |
| Male | 7973 (44.3%) | 7832 (43.5%) | 1.03 | (0.99 to 1.08) | 1518 (50.2%) | 12,931 (42.8%) | 1.41 | (1.31 to 1.52) |
| Contact with RHS | ||||||||
| <5 | 7430 (41.3%) | 7258 (40.6%) | 1.00 | (ref.) | 402 (13.3%) | 7674 (25.4%) | 1.00 | (ref.) |
| 6 to 100 | 8392 (46.6%) | 8815 (49.0%) | 1.06 | (1.01 to 1.12) | 1445 (47.8%) | 16,240 (53.7%) | 1.60 | (1.41 to 1.82) |
| ≥100 | 2174 (12.1%) | 1923 (10.7%) | 1.43 | (1.31 to 1.56) | 1.176 (38.9%) | 6316 (20.9%) | 3.19 | (2.76 to 3.69) |
| Vaccine type | ||||||||
| mRNA-based | 14,432 (80.2%) | 14,571 (81.0%) | 1.00 | (ref.) | 2657 (87.9%) | 26,617 (88.0%) | 1.00 | (ref.) |
| Adenovirus-vectored | 3564 (19.8%) | 3425 (19.0%) | 1.33 | (1.24 to 1.44) | 366 (12.1%) | 3613 (12.0%) | 0.97 | (0.83 to 1.15) |
| Previous SARS-CoV-2 infection | ||||||||
| No | 17,824 (99.0%) | 16,957 (99.0%) | 1.00 | (ref.) | 2922 (96.7%) | 28,799 (95.3%) | 1.00 | (ref.) |
| Yes | 172 (1.0%) | 1039 (5.8%) | 0.15 | (0.13 to 0.88) | 101 (3.3%) | 1431 (4.7%) | 0.67 | (0.54 to 0.84) |
Footnote. Left panel. Analysis included 17,996 patients who, starting from at least 14 days after completing scheduled vaccine, experienced ascertained SARS-CoV-2 infection documented by nasopharyngeal swab testing positive for the nucleic acids of SARS-CoV-2 (infection cases), and 17,996 controls randomly selected to be 1:1 matched for date of vaccination completion and municipality of residence, and for not having yet experienced the infection on the date on which the corresponding case experienced it (index date). Right panel. Analysis included 3023 patients who, starting from at least 14 days after completing scheduled vaccine, experienced COVID-19 hospital admission, including those in an intensive care unit, or death (severe illness cases), and 30,230 controls randomly selected to be 1:10 matched for date of vaccination completion and municipality of residence, and for not having yet experienced the severe illness on the date on which the corresponding case experienced it (index date). Restricted cubic spline with four knots was used for flexibly modelling the relationship between age and odds of both infection and illness (upper boxes). Adjusted odds ratios, and 95% confidence bands, relative to 40 years old reference age, are presented. Number of cases and controls and corresponding column percentage are reported for each feature considered in the bottom panels. Conditional logistic regression model including all the considered features as covariates were fitted for estimating odds ratios and corresponding 95% confidence interval.