Table 1.
Descriptive characteristics of long term care residents tested for SARS-CoV-2 between 30 December 2021 and 27 April 2022 in Ontario, Canada, comparing omicron cases with SARS-CoV-2 negative controls. Values are numbers (percentages) unless stated otherwise
| SARS-CoV-2 negative (n=205 862) | Omicron positive (n=13 654) | Standardised difference* | |
|---|---|---|---|
| Unvaccinated | 5473 (2.7) | 572 (4.2) | 0.08 |
| Vaccination dose received: | |||
| 1 dose | 928 (0.5) | 96 (0.7) | 0.03 |
| 2 doses | 10 924 (5.3) | 1215 (8.9) | 0.14 |
| 3 doses: | |||
| ≥84 days before test | 82 567 (40.1) | 6175 (45.2) | 0.10 |
| <84 days before test | 27 137 (13.2) | 1769 (13.0) | 0.01 |
| 4 doses: | |||
| <7 days before test | 11 035 (5.4) | 646 (4.7) | 0.03 |
| ≥7 days before test | 67 798 (32.9) | 3181 (23.3) | 0.22 |
| Mean (SD) age (years) | 83.63 (9.47) | 83.95 (9.31) | 0.03 |
| Age group (years) | |||
| 60-69 | 19 996 (9.7) | 1204 (8.8) | 0.03 |
| 70-79 | 43 104 (20.9) | 2803 (20.5) | 0.01 |
| ≥80 | 142 762 (69.3) | 9647 (70.7) | 0.03 |
| Men | 65 353 (31.7) | 4749 (34.8) | 0.06 |
| Public health unit region: | |||
| Central East | 15 722 (7.6) | 1017 (7.4) | 0.01 |
| Central West | 34 407 (16.7) | 3218 (23.6) | 0.17 |
| Durham | 7670 (3.7) | 505 (3.7) | 0.00 |
| Eastern | 19 781 (9.6) | 1138 (8.3) | 0.04 |
| North | 19 647 (9.5) | 1487 (10.9) | 0.04 |
| Ottawa | 10 828 (5.3) | 839 (6.1) | 0.04 |
| Peel | 11 473 (5.6) | 494 (3.6) | 0.09 |
| South West | 28 442 (13.8) | 2109 (15.4) | 0.05 |
| Toronto | 43 581 (21.2) | 2235 (16.4) | 0.12 |
| York | 13 396 (6.5) | 578 (4.2) | 0.10 |
| Missing | 915 (0.4) | 34 (0.2) | 0.03 |
| Covid-19 outbreak in long term care facility at time of test | 105 100 (51.1) | 8940 (65.5) | 0.30 |
| Past SARS-CoV-2 positive test result (>90 days) | 32 205 (15.6) | 1021 (7.5) | 0.26 |
| Week of test†: | |||
| 30 Dec to 5 Jan | 29 986 (14.6) | 1949 (14.3) | 0.01 |
| 6 Jan to 12 Jan | 30 124 (14.6) | 2475 (18.1) | 0.09 |
| 13 Jan to 19 Jan | 23 069 (11.2) | 1938 (14.2) | 0.09 |
| 20 Jan to 26 Jan | 19 729 (9.6) | 1526 (11.2) | 0.05 |
| 27 Jan to 2 Feb | 15 607 (7.6) | 989 (7.2) | 0.01 |
| 3 Feb to 9 Feb | 10 391 (5.0) | 532 (3.9) | 0.06 |
| 10 Feb to 16 Feb | 6934 (3.4) | 269 (2.0) | 0.09 |
| 17 Feb to 23 Feb | 5808 (2.8) | 187 (1.4) | 0.10 |
| 24 Feb to 2 Mar | 6034 (2.9) | 173 (1.3) | 0.12 |
| 3 Mar to 9 Mar | 5199 (2.5) | 173 (1.3) | 0.09 |
| 10 Mar to 16 Mar | 5467 (2.7) | 193 (1.4) | 0.09 |
| 17 Mar to 23 Mar | 5595 (2.7) | 203 (1.5) | 0.09 |
| 24 Mar to 30 Mar | 6469 (3.1) | 279 (2.0) | 0.07 |
| 31 Mar to 6 Apr | 7825 (3.8) | 454 (3.3) | 0.03 |
| 7 Apr to 13 Apr | 9406 (4.6) | 584 (4.3) | 0.01 |
| 14 Apr to 20 Apr | 9005 (4.4) | 797 (5.8) | 0.07 |
| 21 Apr to 27 Apr | 9214 (4.5) | 933 (6.8) | 0.10 |
| Mean (SD) No of comorbidities | 4.09 (1.56) | 4.08 (1.55) | 0.01 |
| Type of comorbidity: | |||
| Immunocompromised | 19 226 (9.3) | 1342 (9.8) | 0.02 |
| Chronic respiratory disease | 74 633 (36.3) | 5004 (36.6) | 0.01 |
| Chronic heart disease | 77 159 (37.5) | 4998 (36.6) | 0.02 |
| Hypertension | 168 244 (81.7) | 11 144 (81.6) | 0.00 |
| Diabetes | 82 128 (39.9) | 5252 (38.5) | 0.03 |
| Autoimmune disorders | 16 811 (8.2) | 1058 (7.7) | 0.02 |
| Chronic kidney disease or dialysis‡ | 36 080 (17.5) | 2244 (16.4) | 0.03 |
| Advanced liver disease | 5351 (2.6) | 336 (2.5) | 0.01 |
| Dementia | 160 756 (78.1) | 10 825 (79.3) | 0.03 |
| History of stroke or transient ischaemic attack |
36 467 (17.7) | 2336 (17.1) | 0.02 |
| Frailty | 165 659 (80.5) | 11 157 (81.7) | 0.03 |
SD=standard deviation.
*
Values >0.10 are considered clinically relevant. Comparing omicron cases with SARS-CoV-2 test negative controls.
†
30 December, 31 December in 2021, and remaining dates in 2022.
‡
Chronic kidney disease in past five years or dialysis for three consecutive months.