Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Mar 25:1-10.
doi: 10.1017/dmp.2021.78. Online ahead of print.

SARS-CoV-2 Transmission in Alberta, British Columbia, and Ontario, Canada, December 25, 2019, to December 1, 2020

Isaac Chun-Hai Fung  1 , Yuen Wai Hung  2 , Sylvia K Ofori  1 , Kamalich Muniz-Rodriguez  1 , Po-Ying Lai  3 , Gerardo Chowell  4
Affiliations

SARS-CoV-2 Transmission in Alberta, British Columbia, and Ontario, Canada, December 25, 2019, to December 1, 2020

Isaac Chun-Hai Fung et al. Disaster Med Public Health Prep. .

Abstract

Objective: This study aimed to investigate coronavirus disease (COVID-19) epidemiology in Alberta, British Columbia, and Ontario, Canada.

Methods: Using data through December 1, 2020, we estimated time-varying reproduction number, Rt, using EpiEstim package in R, and calculated incidence rate ratios (IRR) across the 3 provinces.

Results: In Ontario, 76% (92 745/121 745) of cases were in Toronto, Peel, York, Ottawa, and Durham; in Alberta, 82% (49 878/61 169) in Calgary and Edmonton; in British Columbia, 90% (31 142/34 699) in Fraser and Vancouver Coastal. Across 3 provinces, Rt dropped to ≤ 1 after April. In Ontario, Rt would remain < 1 in April if congregate-setting-associated cases were excluded. Over summer, Rt maintained < 1 in Ontario, ~1 in British Columbia, and ~1 in Alberta, except early July when Rt was > 1. In all 3 provinces, Rt was > 1, reflecting surges in case count from September through November. Compared with British Columbia (684.2 cases per 100 000), Alberta (IRR = 2.0; 1399.3 cases per 100 000) and Ontario (IRR = 1.2; 835.8 cases per 100 000) had a higher cumulative case count per 100 000 population.

Conclusions: Alberta and Ontario had a higher incidence rate than British Columbia, but Rt trajectories were similar across all 3 provinces.

Keywords: COVID-19; Canada; SARS-CoV-2; coronavirus; epidemiology; infectious disease; transmission.

PubMed Disclaimer

Figures

Figure 1.
Figure 1.
The daily number of new cases (left) and R t (right) of COVID-19 in Ontario (upper panel), Toronto Public Health (middle panel), and Peel Public Health (lower panel) by the assumed date of infection from December 25, 2019, through December 1, 2020.
Figure 2.
Figure 2.
The daily number of new cases (left) and R t (right) of COVID-19 in York Region Public Health (upper panel), Ottawa Public Health (middle panel), and Durham Public Health (lower panel) by the assumed date of infection from December 25, 2019, through December 1, 2020.
Figure 3.
Figure 3.
The daily number of new cases (left) and R t (right) of COVID-19 in British Columbia (upper panel), Fraser (middle panel), and Vancouver Coastal (lower panel) by the assumed date of infection from January 1 through December 1, 2020.
Figure 4.
Figure 4.
The daily number of new cases (left) and R t (right) of COVID-19 in Alberta (upper panel), Calgary Zone (middle panel), and Edmonton Zone (lower panel) by the assumed date of infection from January 1 through December 1, 2020.
Figure 5.
Figure 5.
Map of the cumulative number of cases in Ontario by public health unit.
Figure 6.
Figure 6.
Map of the cumulative number of cases in Alberta by health service zone.
Figure 7.
Figure 7.
Map of the cumulative number of cases in British Columbia by health authority.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Silverstein WK, Stroud L, Cleghorn GE, Leis JA. First imported case of 2019 novel coronavirus in Canada, presenting as mild pneumonia. Lancet. 2020;395(10225):734. - PMC - PubMed
    1. Marchand-Senecal X, Kozak R, Mubareka S, et al. Diagnosis and management of first case of COVID-19 in Canada: lessons applied from SARS. Clin Infect Dis. 2020;71(16):2207-2210, 10.1093/cid/ciaa227. - DOI - PMC - PubMed
    1. National Post. As the COVID-19 pandemic hit, provinces declared states of emergency. Now many are up for renewal. April 15, 2020. https://nationalpost.com/news/provincial-states-of-emergencies-were-issu.... Accessed May 2, 2020.
    1. The Globe and Mail. Coronavirus March 17: Ontario, Alberta, B.C. declare states of emergency; B.C. closes schools to combat virus spread. March 17, 2020. https://www.theglobeandmail.com/canada/article-the-latest-on-the-coronav.... Accessed April 7, 2020.
    1. Government of Canada. Coronavirus disease (COVID-19): outbreak update (as of December 15, 2020). 2020. https://www.canada.ca/en/public-health/services/diseases/2019-novel-coro.... Accessed December 15, 2020.

LinkOut - more resources