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

International Journal of Infectious Diseases

Dirk Douwes-Schultz¹  Mathieu Maheu-Giroux²  Alexandra M Schmidt²  Yannan Shen³  Mélanie Drolet³  Marc Brisson³  David L Buckeridge³  Maxime Lavigne³  Arnaud Godin³  Yiqing Xia³  Sharmistha Mishra⁴ 

[1] St. Michael’s Hospital, University of Toronto, Institute of Health Policy, Management and Evaluation, Toronto, Ontario, Canada;Centre de Recherche du CHU de Quebec and Département de Médecine Sociale et Préventive, Université Laval, Ville de Quebec, Quebec, Canada;Department of Epidemiology, Biostatistics, and Occupational Health, School of Population and Global Health, McGill University, Montréal, Quebec, Canada;Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Unity Health Toronto, Department of Medicine, Toronto, Ontario, Canada;

关键词: Case introductions;    Epidemiology;    Infectious diseases;    Public health;    Travel;   

DOI  :  

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown