Table 5.
Acute period outcomes (28 days following index) across periods of Omicron subvariants prevalence
| Outcome | Period 1 (BA.1 predominant, BA.2 < 25% prevalence) (n = 2102) |
Period 2 (25% > BA.2 < 75% prevalence) (n = 993) |
Period 3 (BA.2 > 75% prevalence) (n = 3884) |
Period 4 (BA.5 < 25% prevalence) (n = 573) |
Period 5 (25% > BA.5 < 75% prevalence) (n = 1161) |
Period 6 (BA.5 > 75% prevalence) (n = 1383) |
|---|---|---|---|---|---|---|
| COVID-19-attributable hospitalization, n (%) | 22 (1.0) | 13 (1.3) | 37 (1.0) | 6 (1.0) | 16 (1.4) | 10 (0.7) |
| Incidence rate per 100 patient-days | 0.040 | 0.050 | 0.036 | 0.040 | 0.052 | 0.028 |
|
Incidence rate ratioa (95% CI) |
REF |
1.16 (0.58–2.31) |
0.76 (0.44–1.30) |
0.8 (0.32–1.99) |
1.07 (0.56–2.06) |
0.56 (0.26–1.19) |
| P-value | REF | 0.67 | 0.31 | 0.63 | 0.83 | 0.13 |
a Incidence of hospitalization = (hospitalizations observed/total person time in days) × 100
CI, confidence interval; COVID-19, coronavirus disease 2019; REF, reference group