Table 1. Characteristics of Cases and Controls.
| Characteristic | No. (%) | |||||
|---|---|---|---|---|---|---|
| All registered patientsa | Hospitalized patients, death outcomeb | |||||
| Death outcome | Hospitalization or death outcome | Case group (n = 6602) | Control group (n = 24 513) | |||
| Case group (n = 9362) | Control group (n = 37 448) | Case group (n = 32 832) | Control group (n = 131 328) | |||
| Age, y | ||||||
| 18-49 | 104 (1.1) | 416 (1.1) | 3149 (9.6) | 12 924 (9.8) | 64 (1.0) | 2792 (11.4) |
| 50-64 | 580 (6.2) | 2320 (6.2) | 4137 (12.6) | 18 363 (14.0) | 342 (5.2) | 3281 (13.4) |
| 65-79 | 2087 (22.3) | 8347 (22.3) | 9104 (27.7) | 58 656 (44.7) | 1412 (21.4) | 6808 (27.8) |
| ≥80 | 6591 (70.4) | 26 365 (70.4) | 16 442 (50.1) | 41 385 (31.5) | 4784 (72.5) | 11 632 (47.5) |
| Sex | ||||||
| Female | 3834 (41.0) | 15 291 (40.8) | 16 930 (47.4) | 66 625 (46.6) | 2746 (41.6) | 11 875 (48.4) |
| Male | 5528 (59.0) | 22 157 (59.2) | 18 810 (52.6) | 76 335 (53.4) | 3856 (58.4) | 12 638 (51.6) |
| Vaccination status | ||||||
| Unvaccinated | 5813 (62.1) | 13 838 (37.0) | 16 236 (49.5) | 28 124 (21.4) | 4605 (69.8) | 11 435 (46.6) |
| 1 Dose of BNT162b2 | 170 (1.8) | 889 (2.4) | 863 (2.6) | 3907 (3.0) | 110 (1.7) | 695 (2.8) |
| 1 Dose of CoronaVac | 1282 (13.7) | 6501 (17.4) | 5460 (16.6) | 19 765 (15.1) | 1047 (15.9) | 4271 (17.4) |
| 2 Doses of BNT162b2 | 730 (7.8) | 4724 (12.6) | 3068 (9.3) | 23 151 (17.6) | 151 (2.3) | 2479 (10.1) |
| 2 Doses of CoronaVac | 1121 (12.0) | 8132 (21.7) | 5317 (16.2) | 33 528 (25.5) | 613 (9.3) | 4238 (17.3) |
| 3 Doses of BNT162b2 | 79 (0.8) | 922 (2.5) | 640 (1.9) | 7166 (5.5) | 16 (0.2) | 474 (1.9) |
| 3 Doses of CoronaVac | 137 (1.5) | 2031 (5.4) | 1032 (3.1) | 12 728 (9.7) | 49 (0.7) | 768 (3.1) |
| Mixed doses (ie, 2 doses of CoronaVac with 1 dose of BNT162b2) | 30 (0.3) | 411 (1.1) | 216 (0.7) | 2959 (2.3) | 11 (0.2) | 153 (0.6) |
| Detection methods | ||||||
| PCR testing | 8827 (94.3) | 24 884 (66.4) | 28 624 (87.2) | 77 134 (58.7) | 6067 (91.9) | 20 559 (83.9) |
| RAT | 535 (5.7) | 12 564 (33.6) | 4208 (12.8) | 54 194 (41.3) | 535 (8.1) | 3954 (16.1) |
| Chronic conditions or cancer | ||||||
| Hypertension | NA | NA | NA | NA | 2211 (33.5) | 8454 (34.5) |
| Diabetes | NA | NA | NA | NA | 1276 (19.3) | 4790 (19.5) |
| Other cardiovascular diseases | NA | NA | NA | NA | 1703 (25.8) | 6532 (26.6) |
| Cancer | NA | NA | NA | NA | 481 (7.3) | 1706 (7.0) |
| Chronic lung disease | NA | NA | NA | NA | 416 (6.3) | 1444 (5.9) |
| Chronic kidney disease | NA | NA | NA | NA | 500 (7.6) | 1884 (7.7) |
| Chronic liver disease | NA | NA | NA | NA | 336 (5.1) | 1308 (5.3) |
| Obesity | NA | NA | NA | NA | 206 (3.1) | 865 (3.5) |
| Inpatient treatment received | ||||||
| Molnupiravir | NA | NA | NA | NA | 540 (8.2) | 2799 (11.4) |
| Paxlovid | NA | NA | NA | NA | 137 (2.1) | 920 (3.8) |
| Remdesivir | NA | NA | NA | NA | 1162 (17.6) | 2080 (8.5) |
| Subcutaneous interferon β-1b | NA | NA | NA | NA | 318 (4.8) | 421 (1.7) |
| Dexamethasone | NA | NA | NA | NA | 4684 (70.9) | 6823 (27.8) |
| Intravenous tocilizumub | NA | NA | NA | NA | 157 (2.4) | 123 (0.5) |
Abbreviations: NA, not applicable; PCR, polymerase chain reaction; RAT, rapid antigen test.
a
All registered patients included those aged 18 years or older who were diagnosed with a positive PCR test or RAT during the study period.
b
Hospitalized patients included all local patients aged 18 years or older who were hospitalized and diagnosed with Omicron infection by genomic sequencing. Their hospitalization records were linked with the test results to provide details on comorbidities and inpatient treatment received.