Table 2. The attack rates of the omicron variant compared to the delta variant.
| Variables | Delta | Omicron | Delta vs. Omicron | ||||
|---|---|---|---|---|---|---|---|
| Subtotal of inpatients & staff members, n (%) | Confirmed cases, n (attack rate, %) | Subtotal of inpatients & staff members, n (%) | Confirmed cases, n (attack rate, %) | Relative risk (95% CI) | Adjusted relative risk (95% CI) | ||
| Total | 544 (100) | 101 (18.6) | 605 (100) | 193 (31.9) | 2.05 (1.56–2.71) | 2.24 (1.68–3.00) | |
| Gender | |||||||
| Male | 189 (34.7) | 61 (32.3) | 198 (32.7) | 72 (36.4) | 1.20 (0.79–1.83) | 1.29 (0.83–2.00) | |
| Female | 355 (65.3) | 40 (11.3) | 407 (67.3) | 121 (29.7) | 3.33 (2.25–4.93) | 3.52 (2.35–5.29) | |
| Age, years | |||||||
| ≤59 | 189 (34.7) | 10 (5.3) | 197 (32.6) | 45 (22.8) | 5.30 (2.58–10.87) | 6.43 (3.02–13.68) | |
| 60–74 | 168 (30.9) | 48 (28.6) | 185 (30.6) | 67 (36.2) | 1.42 (0.91–2.22) | 1.59 (1.00–2.54) | |
| ≥75 | 187 (34.4) | 43 (23.0) | 223 (36.9) | 81 (36.3) | 1.91 (1.23–2.96) | 2.01 (1.27–3.17) | |
| Group | |||||||
| Inpatients | 301 (55.3) | 88 (29.2) | 318 (52.6) | 116 (36.5) | 1.39 (0.99–1.95) | 1.45 (1.02–2.06) | |
| Staff members | 243 (44.7) | 13 (5.3) | 287 (47.4) | 77 (26.8) | 6.49 (3.50–12.02) | 7.10 (3.75–13.46) | |
| Vaccination status | |||||||
| Unvaccinated | 87 (16.0) | 28 (32.2) | 58 (9.6) | 21 (36.2) | 1.20 (0.59–2.41) | 1.19 (0.58–2.43) | |
| First | 18 (3.3) | 9 (50.0) | 19 (3.1) | 5 (26.3) | 0.36 (0.09–1.42) | 0.35 (0.08–1.48) | |
| Second | 154 (28.3) | 36 (23.4) | 100 (16.5) | 25 (25.0) | 1.09 (0.61–1.96) | 0.99 (0.54–1.81) | |
| Third | 285 (52.4) | 28 (9.8) | 428 (70.7) | 142 (33.2) | 4.56 (2.94–7.07) | 4.49 (2.86–7.04) | |
CI, confidence interval.