Table 2.
Outcomes for the Omicron Cohort Compared With the Influenza and RSV Cohorts
| Descriptive Data | Omicron Versus Influenza | Omicron Versus RSV | |||||
|---|---|---|---|---|---|---|---|
| Omicron | Influenza | RSV | Unadjusted Ratio (95% CI) |
Adjusted Ratioa (95% CI) |
Unadjusted Ratio (95% CI) |
Adjusted Ratioa (95% CI) |
|
| 30-day all-cause mortalityb | |||||||
| Main cohorts | 381/4833 (7.9) | 28/1099 (2.5) | 27/453 (6.0) | 3.27 (2.26–4.94) | 2.36 (1.60–3.62) | 1.35 (.92–2.07) | 1.42 (.94–2.21) |
| Unvaccinated Omicronc | 90/1068 (8.4) | 28/1099 (2.5) | 27/453 (6.0) | 3.52 (2.31–5.52) | 5.51 (3.41–9.18) | 1.45 (.94–2.30) | 3.29 (2.01–5.56) |
| Vaccinated Omicrond | 283/3625 (7.8) | 28/1099 (2.5) | 27/453 (6.0) | 3.24 (2.22–4.91) | 2.00 (1.35–3.10) | 1.34 (.91–2.05) | 1.20 (.79–1.88) |
| Pre-pandemic influenza and RSV | 381/4833 (7.9) | 192/5709 (3.4) | 63/995 (6.3) | 2.46 (2.06–2.94) | 2.17 (1.80–2.62) | 1.27 (.97–1.68) | 1.49 (1.12–2.01) |
| 90-day all-cause mortalityb,e | |||||||
| Main cohorts | 424/3854 (11.0) | 40/1077 (3.7) | 39/453 (8.7) | 3.15 (2.31–4.43) | 2.31 (1.65–3.30) | 1.30 (.93–1.85) | 1.40 (.98–2.03) |
| Unvaccinated Omicronc | 94/942 (10.0) | 40/1077 (3.7) | 39/453 (8.7) | 2.87 (1.98–4.25) | 4.94 (3.17–7.88) | 1.18 (.81–1.75) | 2.72 (1.75–4.31) |
| Vaccinated Omicrond | 318/2797 (11.4) | 40/1077 (3.7) | 39/453 (8.7) | 3.33 (2.40–4.72) | 2.17 (1.53–3.16) | 1.35 (.96–1.93) | 1.27 (.88–1.88) |
| Pre-pandemic influenza and RSV | 424/3854 (11.0) | 293/5709 (5.1) | 96/995 (9.6) | 2.28 (1.96–2.67) | 2.09 (1.77–2.48) | 1.16 (.92–1.47) | 1.43 (1.12–1.85) |
| Hospital admissionf | |||||||
| Main cohorts | 2449/4833 (50.7) | 435/1099 (39.6) | 291/453 (64.2) | 1.37 (1.24–1.52) | 0.97 (.88–1.08) | 0.68 (.60–.77) | 0.73 (.64–.82) |
| Unvaccinated Omicronc | 494/1068 (46.3) | 435/1099 (39.6) | 291/453 (64.2) | 1.21 (1.07–1.38) | 1.30 (1.14–1.49) | 0.60 (.52–.70) | 0.92 (.79–1.08) |
| Vaccinated Omicrond | 1900/3625 (52.4) | 435/1099 (39.6) | 291/453 (64.2) | 1.44 (1.30–1.60) | 0.90 (.81–1.00) | 0.71 (.63–.81) | 0.68 (.60–.78) |
| Pre-pandemic influenza and RSV | 2449/4833 (50.7) | 3024/5709 (53.0) | 668/995 (67.1) | 0.93 (.88–.98) | 0.84 (.79–.89) | 0.64 (.59–.70) | 0.75 (.69–.82) |
| ICU admissionf | |||||||
| Main cohorts | 140/4833 (2.9) | 11/1099 (1.0) | 10/453 (2.2) | 2.93 (1.59–5.42) | 2.49 (1.34–4.63) | 1.32 (.69–2.50) | 1.40 (.74–2.67) |
| Unvaccinated Omicronc | 54/1068 (5.1) | 11/1099 (1.0) | 10/453 (2.2) | 5.16 (2.70–9.87) | 4.96 (2.56–9.60) | 2.31 (1.18–4.54) | 2.82 (1.39–5.73) |
| Vaccinated Omicrond | 83/3625 (2.3) | 11/1099 (1.0) | 10/453 (2.2) | 2.31 (1.23–4.34) | 1.88 (.98–3.61) | 1.04 (.54–2.00) | 1.08 (.56–2.10) |
| Pre-pandemic influenza and RSV | 140/4833 (2.9) | 186/5709 (3.3) | 50/995 (5.0) | 0.89 (.71–1.10) | 0.86 (.69–1.07) | 0.57 (.41–.78) | 0.58 (.41–.80) |
Abbreviations: COVID-19, coronavirus disease 2019; CI, confidence interval; ICU, intensive care unit; RSV, respiratory syncytial virus.
aAdjusted for age, sex, being born in Sweden, education level, and all studied comorbidities.
bAnalysed with logistic regression models.
cDefined as having received zero COVID-19 vaccine doses 14 days or more before the emergency department visit.
dDefined as having received 2 or more COVID-19 vaccine doses 14 days or more before the emergency department visit.
eRestricted to individuals visiting the emergency department up until 17 July 2022 to allow for 90-days of follow-up.
fAnalysed with Cox proportional hazard regression models.