Characteristics of 2 472 261 individuals in Ontario, Canada, aged 12 years and older, with known ABO blood group and without evidence of SARS-CoV-2 infection before 15 January 2021. All data are presented as a number (%) unless otherwise indicated
| Characteristic | Any SARS-CoV-2 vaccination (N=1 743 916) | No SARS-CoV-2 vaccination (N=728 345) | Standardised difference | |
| On 15 January 2021 (time zero) | ||||
| Mean (SD) age, year | 50.8 (18.4) | 40.6 (15.4) | 0.60 | |
| 12–17 | 13 009 (0.7) | 11 509 (1.6) | 0.08 | |
| 18–39 | 589 158 (33.8) | 415 983 (57.1) | 0.48 | |
| 40–59 | 568 693 (32.6) | 208 310 (28.6) | 0.09 | |
| 60–69 | 218 653 (12.5) | 42 386 (5.8) | 0.23 | |
| 70–79 | 209 118 (12.0) | 29 116 (4.0) | 0.30 | |
| 80+ | 145 285 (8.3) | 21 041 (2.9) | 0.24 | |
| Female | 1 200 499 (68.8) | 548 647 (75.3) | 0.15 | |
| Area income quintile (Q)* | Q1 (lowest) | 298 360 (17.1) | 182 483 (25.1) | 0.20 |
| Q2 | 332 128 (19.0) | 153 526 (21.1) | 0.05 | |
| Q3 | 360 666 (20.7) | 147 174 (20.2) | 0.01 | |
| Q4 | 375 199 (21.5) | 134 421 (18.5) | 0.08 | |
| Q5 (highest) | 373 655 (21.4) | 108 469 (14.9) | 0.17 | |
| Rural residence† | Rural | 164 607 (9.4) | 76 733 (10.5) | 0.04 |
| Pregnant | 23 137 (1.3) | 19 410 (2.7) | 0.10 | |
| O blood group | 315 903 (43.4) | 751 212 (43.1) | 0.01 | |
| Pre-existing conditions | ||||
| Diabetes mellitus | 292 661 (16.8) | 70 062 (9.6) | 0.21 | |
| Malignancy | 405 034 (23.2) | 104 741 (14.4) | 0.23 | |
| Heart failure | 89 604 (5.1) | 18 085 (2.5) | 0.14 | |
| Cardiac ischaemia or arrhythmia | 144 692 (8.3) | 27 106 (3.7) | 0.19 | |
| Chronic kidney disease | 90 732 (5.2) | 19 760 (2.7) | 0.13 | |
| Venous thromboembolism | 41 006 (2.4) | 13 342 (1.8) | 0.04 | |
| Stroke or transient ischaemic attack | 31 638 (1.8) | 6763 (0.9) | 0.08 | |
| Chronic hypertension | 571 167 (32.8) | 116 201 (16.0) | 0.40 | |
| Asthma | 300 546 (17.2) | 126 172 (17.3) | 0.00 | |
| Dementia, or frailty | 264 694 (15.2) | 107 972 (14.8) | 0.01 | |
| Anaemia | 265 861 (15.2) | 96 060 (13.2) | 0.06 | |
| Chronic obstructive pulmonary disease | 89 413 (5.1) | 20 352 (2.8) | 0.12 | |
| HIV or organ transplant | 9754 (0.6) | 2770 (0.4) | 0.03 | |
| At time of first vaccination | ||||
| Vaccine type | Modified RNA | 1 600 524 (91.8) | -- | -- |
| Adenovirus-vectored | 143 358 (8.2) | -- | -- | |
| Unspecified | 34 (0.0) | -- | -- | |
| Vaccine name | AstraZeneca | 117 100 (6.7) | -- | -- |
| Covishield | 26 086 (1.5) | -- | -- | |
| Janssen | 172 (0.0) | -- | -- | |
| Moderna | 315 370 (18.1) | -- | -- | |
| Pfizer | 1 285 154 (73.7) | -- | -- | |
| Unspecified | 34 (0.0) | -- | -- | |
| At the time of second vaccination | ||||
| Vaccine type | Modified RNA | 415 632 (23.8) | -- | -- |
| Adenovirus-vectored | 12 855 (0.7) | -- | -- | |
| Unspecified | 16 (0.0) | -- | -- | |
| No second dose | 1 315 413 (75.4) | -- | -- | |
| Vaccine name | AstraZeneca | 12 692 (0.7) | ||
| Covishield | 157 (0.0) | -- | ||
| Janssen | 6 (0.0) | -- | ||
| Moderna | 86 791 (5.0) | -- | ||
| Pfizer | 328 841 (18.9) | -- | ||
| Unspecified | 16 (0.0) | -- | ||
| No second dose | 1 315 413 (75.4) | -- | ||
| Received two vaccine doses by 13 June 2021 (14 days prior to end of follow-up) | 428 503 (24.6) | -- | ||
| Vaccine dose 2 same as dose 1 | Same | 424 517 (24.3) | -- | |
| Different | 3969 (0.2) | -- | ||
| Unknown | 17 (0.0) | -- | ||
| No second dose | 1 315 413 (75.4) | |||
| Median (IQR) follow-up for assessing the primary study outcome, d | 163.0 (163.0–163.0) | 163.0 (163.0–163.0) | 0.39 | |
| Median (IQR) follow-up for assessing the secondary study outcome, d | 163.0 (163.0–163.0) | 163.0 (163.0–163.0) | 0.16 | |
| Had SARS-CoV-2 PCR testing during follow-up period, from 15 January 2021 onward | 439 058 (25.2) | 175 397 (24.1) | 0.03 | |
*Missing for 6180 (0.25%) of all persons.
†Missing for 5247 (0.21%) of all persons.
‡Before 15 January 2021.