The role of case importation in explaining differences in early SARS-CoV-2 transmission dynamics in Canada—A mathematical modeling study of surveillance data

Autor: Arnaud Godin, Yiqing Xia, David L Buckeridge, Sharmistha Mishra, Dirk Douwes-Schultz, Yannan Shen, Maxime Lavigne, Mélanie Drolet, Alexandra M Schmidt, Marc Brisson, Mathieu Maheu-Giroux
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: International Journal of Infectious Diseases, Vol 102, Iss , Pp 254-259 (2021)
Druh dokumentu: article
ISSN: 1201-9712
DOI: 10.1016/j.ijid.2020.10.046
Popis: Objective: The North American coronavirus disease-2019 (COVID-19) epidemic exhibited distinct early trajectories. In Canada, Quebec had the highest COVID-19 burden and its earlier March school break, taking place two weeks before those in other provinces, could have shaped early transmission dynamics. Methods: We combined a semi-mechanistic model of SARS-CoV-2 transmission with detailed surveillance data from Quebec and Ontario (initially accounting for 85% of Canadian cases) to explore the impact of case importation and timing of control measures on cumulative hospitalizations. Results: A total of 1544 and 1150 cases among returning travelers were laboratory-confirmed in Quebec and Ontario, respectively (symptoms onset ≤03-25-2020). Hospitalizations could have been reduced by 55% (95% CrI: 51%–59%) if no cases had been imported after Quebec’s March break. However, if Quebec had experienced Ontario’s number of introductions, hospitalizations would have only been reduced by 12% (95% CrI: 8%–16%). Early public health measures mitigated the epidemic spread as a one-week delay could have resulted in twice as many hospitalizations (95% CrI: 1.7–2.1). Conclusion: Beyond introductions, factors such as public health preparedness, responses and capacity could play a role in explaining interprovincial differences. In a context where regions are considering lifting travel restrictions, coordinated strategies and proactive measures are to be considered.
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