Outcome of patients hospitalised for COVID-19 during the first 10 weeks of 2022 (Omicron era) and for influenza, the 10-week peak of 2009/2010 (H1N1 pandemic), 2015/2016 (higher severity in children) and 2016/2017 (higher severity in adults) by age group, British Columbia, Canada
| Outcome by age groups (year) | COVID-19 (n=2561) | Influenza 2009/2010 (n=1395) | Influenza 2015/2016 (n=655) | Influenza 2016/2017 (n=1443) |
| Hospital length of stay, days, Median (IQR) | ||||
| All ages | 6 (3–13) | 3 (2–7) | 5 (2–10) | 6 (3–12) |
| P value | Ref | <0.0001 | <0.0001 | 0.1697 |
| 0–4 | 1 (1–2) | 2 (1–4) | 3 (2–6) | 3 (1–6) |
| 5–11 | 2 (1–3) | 2 (1–5) | 3 (2–6.5) | 2 (1–3) |
| 12–17 | 2 (1–5) | 2 (1–5) | 2 (1–4) | 3 (1–6) |
| 18–29 | 2 (1–5) | 2 (1–4) | 3 (1–5) | 2 (1–3) |
| 30–39 | 3 (2–6) | 3 (1–5) | 3 (2–9) | 3 (1–5) |
| 40–49 | 5 (2–10) | 4 (2–8) | 4 (2–9) | 4 (2–7) |
| 50–59 | 7 (3–13) | 5 (2–9) | 6 (3–14.5) | 4 (2–8) |
| 60–69 | 7 (4–14) | 5 (3–10) | 6 (3–10) | 4 (3–9) |
| 70+ | 8 (4–15) | 6 (3–11) | 7 (4–12) | 7 (4–14) |
| Admission to ICU | ||||
| All ages | 472 (18%) | 216 (15%) | 151 (23%) | 157 (11%) |
| P value | Ref | 0.0195 | 0.0075 | <0.0001 |
| 0–4 | 13 (3%) | 12 (6%) | 16 (11%) | 16 (10%) |
| 5–11 | 5 (1%) | 14 (6%) | 8 (5%) | 7 (5%)* |
| 12–17 | <5 | <5 | <5 | |
| 18–29 | 12 (3%) | 24 (11%) | 8 (5%) | <5 |
| 30–39 | 14 (3%) | 24 (11%) | 8 (5%) | <5 |
| 40–49 | 33 (7%) | 43 (20%) | 15 (10%) | 10 (6%) |
| 50–59 | 77 (16%) | 52 (24%) | 34 (23%) | 19 (12%) |
| 60–69 | 136 (29%) | 25 (12%) | 33 (22%) | 35 (22%) |
| 70+ | 181 (38%) | 18 (8%) | 27 (18%) | 66 (42%) |
| Stay in ICU, days, Median (IQR) | ||||
| All ages | 6 (3–14) | 6 (2–13) | 7 (3–13) | 5 (3–12) |
| P value | Ref | 0.0181 | 0.0063 | <0.0001 |
| 0–4 | 2 (1–3) | 4 (1–13) | 3 (2–5) | 5 (2–11) |
| 5–11 | 3 (1–8) | 2 (1–5) | 5 (2–12) | 3 (2–5)* |
| 12–17 | Sup† | Sup† | Sup† | |
| 18–29 | 3 (2–28) | 5 (2–25) | 4 (2–23) | Sup† |
| 30–39 | 4 (3–12) | 4 (1–6.5) | 6 (2–16) | Sup† |
| 40–49 | 5 (2–14) | 11 (4–27) | 9 (4–12) | 5 (2–8) |
| 50–59 | 7 (3–16) | 7 (4–13) | 10 (6–15) | 6 (3–12) |
| 60–69 | 8 (3–17) | 7 (4–12) | 9 (5–14) | 9 (3–13) |
| 70+ | 7 (3–11) | 8 (3–11) | 5 (3–13) | 6 (3–11) |
For the peak COVID-19 cohort, we included all patients hospitalised for COVID-19 during the first 10 weeks of 2022 when Omicron was dominant and >90% of adults in British Columbia were vaccinated with at least two doses. For influenza peak analysis, we selected data-driven 10-week peak from each season during which the majority of all hospitalised cases of the year were admitted. P values are presenting differences between COVID-19 and each influenza year.
*The two age groups collapsed due to disclosure control.
†Suppressed due to disclosure control.
ICU, intensive care unit; Q, quartile; Ref, reference; Sup, suppressed.