Table 3:
Estimated period-specific risk of hospital admission and death from first-ever SARS-CoV-2 infection, by age group, Lower Mainland, British Columbia, Canada
| Variable | Period-specific estimates, % (95% CrI)* | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Age 0–4 yr | Age 5–9 yr | Age 10–19 yr | Age 20–29 yr | Age 30–39 yr | Age 40–49 yr | Age 50–59 yr | Age 60–69 yr | Age 70–79 yr | Age ≥ 80 yr | Overall | |
| Sixth to seventh serosurvey (Sept. 26, 2021–Mar. 12, 2022; mixed Delta and Omicron BA.1 predominance) | |||||||||||
| No. of hospital admissions | 89 | 22 | 22 | 37 | 94 | 179 | 315 | 461 | 517 | 629 | 2365 |
| No. of deaths | 0 | 0 | 0 | 1 | 6 | 13 | 40 | 82 | 153 | 443 | 738 |
| IHR | 0.13 (0.11–0.15) | 0.026 (0.023–0.030) | 0.015 (0.013–0.019) | 0.019 (0.016–0.023) | 0.041 (0.035–0.049) | 0.12 (0.01–0.15) | 0.31 (0.24–0.43) | 0.62 (0.46–0.90) | 3.27 (1.72–10.48) | 4.71 (2.97–9.65) | 0.22 (0.20–0.24) |
| IFR | 0 | 0 | 0 | 0.0005 (0.0004–0.0006) | 0.0026 (0.0022–0.0032) | 0.009 (0.007–0.011) | 0.04 (0.03–0.05) | 0.11 (0.08–0.16) | 0.97 (0.51–3.10) | 3.32 (2.05–6.79) | 0.068 (0.063–0.074) |
| Seventh to eighth serosurvey (Mar. 13–July 30, 2022; Omicron BA.2 and BA.5 predominance) | |||||||||||
| No. of hospital admissions | 73 | 10 | 9 | 21 | 26 | 28 | 73 | 183 | 310 | 691 | 1424 |
| No. of deaths | 2 | 0 | 0 | 1 | 1 | 1 | 8 | 34 | 51 | 206 | 304 |
| IHR | 0.41 (0.24–0.99) | 0.10 (0.05–0.59) | 0.013 (0.009–0.020) | 0.022 (0.015–0.035) | 0.04 (0.02–0.10) | 0.03 (0.02–0.06) | 0.06 (0.05–0.09) | 0.25 (0.17–0.45) | 0.42 (0.33–0.59) | 2.17 (1.61–3.26) | 0.22 (0.19–0.26) |
| IFR | 0.011 (0.007–0.027) | 0 | 0 | 0.0010 (0.0007–0.0017) | 0.002 (0.001–0.004) | 0.0011 (0.0008–0.0020) | 0.007 (0.005–0.010) | 0.05 (0.03–0.08) | 0.07 (0.05–0.10) | 0.65 (0.48–0.97) | 0.05 (0.04–0.06) |
| Eighth to ninth serosurvey (July 31–Dec. 3, 2022; Omicron BA.5 and BQ.1.1 predominance) | |||||||||||
| No. of hospital admissions | 43 | 2 | 12 | 10 | 20 | 19 | 46 | 112 | 228 | 517 | 1009 |
| No. of deaths | 0 | 0 | 0 | 0 | 0 | 2 | 9 | 18 | 35 | 187 | 251 |
| IHR | 0.29 (0.17–0.84) | 0.010 (0.006–0.021) | 0.06 (0.03–0.28) | 0.014 (0.009–0.029) | 0.03 (0.02–0.05) | 0.03 (0.02–0.08) | 0.11 (0.06–0.34) | 0.16 (0.11–0.32) | 0.73 (0.42–1.95) | 3.51 (1.99–9.85) | 0.24 (0.20–0.31) |
| IFR | 0 | 0 | 0 | 0 | 0 | 0.004 (0.002–0.009) | 0.02 (0.01–0.07) | 0.03 (0.02–0.05) | 0.11 (0.06–0.30) | 1.27 (0.72–3.56) | 0.06 (0.05–0.08) |
Note: CrI = credible interval, IFR = infection fatality ratio, interpreted as risk (%) of dying due to a first-ever SARS-CoV-2 infection acquired during the specified period, IHR = infection hospitalization ratio, interpreted as risk (%) of hospitalization due to a first-ever SARS-CoV-2 infection acquired during the specified period.
Unless indicated otherwise. Period-specific estimates represent a percentage of first-ever SARS-CoV-2 infections. Seroprevalence participants excluded long-term care or assisted living facility residents but neither could be reliably identified among records of hospital admissions and deaths, and were retained. Note that where rounding would otherwise suggest CrIs equal to point estimates, additional decimal points are displayed.