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Volume 30, Number 5—May 2024
Research

SARS-CoV-2 Transmission in Alberta, British Columbia, and Ontario, Canada, January 2020–January 2022

Aubrey D. Kehoe1, Arshpreet Kaur Mallhi1, Charles R. Barton2, Hunter M. Martin2, Christopher M. Turner2, Xinyi Hua, Kin On Kwok, Gerardo Chowell, and Isaac Chun-Hai FungComments to Author 
Author affiliations: Georgia Southern University Jiann-Ping Hsu College of Public Health, Statesboro, Georgia, USA (A.D. Kehoe, A.K. Mallhi, C.R. Barton, H.M. Martin, C.M. Turner, X. Hua, I.C.-H. Fung); Chinese University of Hong Kong JC School of Public Health and Primary Care, Hong Kong (K.O. Kwok); Georgia State University School of Public Health, Atlanta, Georgia, USA (G. Chowell)

Main Article

Table 2

Number of days observed, cumulative case count, cumulative case count per 100,000 person-days, and incidence rate ratio between variants by province, and between provinces by variant in 3 provinces of Canada (Ontario, British Columbia, and Alberta) during January 23, 2020–January 27, 2022*

Category Alberta British Columbia Ontario Overall
Population size, 2021
 4,262,635
 5,000,879
 14,223,942
 23,487,456
No. days observed
Variant
Wild-type 562 573 572 Not applicable
Alpha 602 602 602 Not applicable
Delta 460 460 460 Not applicable
Omicron
 68
 68
 68
 Not applicable
Cumulative case count
Variant
Wild-type 146,910 91,170 337,299 575,379
Alpha 54,621 36,951 133,162 224,734
Delta 116,902 82,441 121,710 321,053
Omicron 141,661 91,491 366,495 599,646
Total (%)
 460,094 (26.74)
 302,053 (17.55)
 958,666 (55.71)
 1,720,812 (100)
Cumulative case count per 100,000 person-days
Variant
Wild-type 6.13 3.18 4.15 4.29
Alpha 2.13 1.23 1.56 1.59
Delta 5.96 3.58 1.86 2.97
Omicron 48.87 26.90 37.89 37.54
Total
 6.38
 3.45
 3.96
 4.31
IRR between variant by province
Variant
Wild-type (95% CI) Referent Referent Referent Referent
Alpha (95% CI) 0.347 (0.344–0.351)† 0.386 (0.381–0.390)† 0.375 (0.373–0.378)† 0.370 (0.368–0.372)†
Delta (95% CI) 0.972 (0.965–0.980)† 1.126 (1.116–1.137)† 0.449 (0.446–0.452)† 0.692 (0.689–0.695)†
Omicron (95% CI)
 7.969 (7.911–8.028)†
 8.456 (8.379–8.534)†
 9.140 (9.097–9.183)†
 8.742 (8.710–8.774)†
IRR between province by variant
Variant
Wild-type (95% CI) 1.927 (1.912–1.943)† Referent 1.303 (1.294–1.313)† Not applicable
Alpha (95% CI) 1.734 (1.711–1.757)† Referent 1.267 (1.252–1.282)† Not applicable
Delta (95% CI) 1.664 (1.649–1.678)† Referent 0.519 (0.514–0.524)† Not applicable
Omicron (95% CI) 1.827 (1.801–1.832)† Referent 1.408 (1.398–1.419)† Not applicable
Overall (95% CI) 1.799 (1.790–1.807)† Referent 1.117 (1.112–1.121)† Not applicable

*IRR, incidence rate ratio. †p<0.0001.

Main Article

1These first authors contributed equally to this article.

2These second authors contributed equally to this article.

Page created: February 29, 2024
Page updated: April 25, 2024
Page reviewed: April 25, 2024
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