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Efficacy of 'Stay-at-Home' Policy and Transmission of COVID-19 in Toronto, Canada: A Mathematical Modeling Study

26 Pages Posted: 13 Oct 2020

See all articles by Pei Yuan

Pei Yuan

York University - Centre for Diseases Modeling (CDM)

Juan Li

York University - Centre for Diseases Modeling (CDM)

Elena Aruffo

York University - Centre for Diseases Modeling (CDM)

Qi Li

York University - Centre for Diseases Modeling (CDM)

Tingting Zheng

York University - Centre for Diseases Modeling (CDM)

Nick Ogden

Public Health Agency Canada - Public Health Risk Sciences Division

Beate Sander

University of Toronto - Toronto Health Economics and Technology Assessment (THETA); University of Toronto - Institute of Health Policy, Management and Evaluation; Public Health Ontario; Institute for Clinical Evaluative Sciences (ICES)

Jane M. Heffernan

York University - Centre for Diseases Modeling (CDM)

Evgenia Gatov

City of Toronto - Toronto Public Health

effie gournis

City of Toronto - Toronto Public Health

Sarah Collier

City of Toronto - Toronto Public Health

Yi Tan

York University - Centre for Diseases Modeling (CDM)

Jun Li

York University - Centre for Diseases Modeling (CDM)

Julien Arino

University of Manitoba - Department of Mathematics

Jacques Belair

York University - Centre for Diseases Modeling (CDM)

James Watmough

York University - Centre for Diseases Modeling (CDM)

Jude Dzevela Kong

York University - Centre for Diseases Modeling (CDM)

Iain Moyles

York University - Centre for Diseases Modeling (CDM)

Huaiping Zhu

York University - Centre for Diseases Modeling (CDM)

More...

Abstract

Background: In many parts of the world, restrictive non-pharmaceutical interventions (NPI) that aim to reduce contact rates, including stay-at-home orders, limitations on gatherings, and closure of public places, are being lifted, with the possibility that the epidemic resurges if alternative measures are not strong enough. Here we aim to capture the combination of use of NPI’s and reopening measures which will prevent an infection rebound.

Methods: We employ an SEAIR model with household structure able to capture the stay-at-home policy (SAHP). To reflect the changes in the SAHP over the course of the epidemic, we vary the SAHP compliance rate, assuming that the time to compliance of all the people requested to stay-at-home follows a Gamma distribution. Using confirmed case data for the City of Toronto, we evaluate basic and instantaneous reproduction numbers and simulate how the average household size, the stay-at-home rate, the efficiency and duration of SAHP implementation, affect the outbreak trajectory.

Findings: The estimated basic reproduction number R_0 was 2.36 (95% CI: 2.28, 2.45) in Toronto. After the implementation of the SAHP, the contact rate outside the household fell by 39%. When people properly respect the SAHP, the outbreak can be quickly controlled, but extending its duration beyond two months (65 days) had little effect. Our findings also suggest that to avoid a large rebound of the epidemic, the average number of contacts per person per day should be kept below nine. This study suggests that fully reopening schools, offices, and other activities, is possible if the use of other NPIs is strictly adhered to.

Interpretation: Our model confirmed that the SAHP implemented in Toronto had a great impact in controlling the spread of COVID-19. Given the lifting of restrictive NPIs, we estimated the thresholds values of maximum number of contacts, probability of transmission and testing needed to ensure that the reopening will be safe, i.e. maintaining an Rt <1.

Funding Statement: This research was supported by Canadian Institutes of Health Research (CIHR), Canadian COVID-19 Math Modelling Task Force (NO, BS, JH, JA, JB, JW, JD, HZ), the Natural Sciences and Engineering Research Council of Canada (JH, JA, JB, JW, JD, IM, HZ) and York University Research Chair program (HZ).

Declaration of Interests: The authors declare no conflict of interest.

Keywords: COVID-19, transmission model, household structure, stay-at-home policy, non-pharmaceutical interventions, reopen

Suggested Citation

Yuan, Pei and Li, Juan and Aruffo, Elena and Li, Qi and Zheng, Tingting and Ogden, Nick and Sander, Beate and Heffernan, Jane M. and Gatov, Evgenia and gournis, effie and Collier, Sarah and Tan, Yi and Li, Jun and Arino, Julien and Belair, Jacques and Watmough, James and Kong, Jude Dzevela and Moyles, Iain and Zhu, Huaiping, Efficacy of 'Stay-at-Home' Policy and Transmission of COVID-19 in Toronto, Canada: A Mathematical Modeling Study. Available at SSRN: https://ssrn.com/abstract=3678581 or http://dx.doi.org/10.2139/ssrn.3678581

Pei Yuan

York University - Centre for Diseases Modeling (CDM)

Canada

Juan Li

York University - Centre for Diseases Modeling (CDM)

Canada

Elena Aruffo

York University - Centre for Diseases Modeling (CDM) ( email )

Canada

Qi Li

York University - Centre for Diseases Modeling (CDM)

Canada

Tingting Zheng

York University - Centre for Diseases Modeling (CDM)

Canada

Nick Ogden

Public Health Agency Canada - Public Health Risk Sciences Division

Ontario
Canada

Beate Sander

University of Toronto - Toronto Health Economics and Technology Assessment (THETA) ( email )

Eaton Building, 10th Floor, Room 247
200 Elizabeth Street
Toronto, M5G 2C4
Canada

University of Toronto - Institute of Health Policy, Management and Evaluation ( email )

Toronto
Canada

Public Health Ontario ( email )

Kingston, Ontario
Canada

Institute for Clinical Evaluative Sciences (ICES) ( email )

Toronto, Ontario M4N M5
Canada

Jane M. Heffernan

York University - Centre for Diseases Modeling (CDM) ( email )

4700 Keele Street
Toronto, Ontario M3J 1P3
Canada

Evgenia Gatov

City of Toronto - Toronto Public Health ( email )

Effie Gournis

City of Toronto - Toronto Public Health ( email )

Sarah Collier

City of Toronto - Toronto Public Health

Yi Tan

York University - Centre for Diseases Modeling (CDM)

Canada

Jun Li

York University - Centre for Diseases Modeling (CDM)

Canada

Julien Arino

University of Manitoba - Department of Mathematics ( email )

501 F.A. Bldg
Winnipeg R3T 5V4, R3T 5V5
Canada

Jacques Belair

York University - Centre for Diseases Modeling (CDM) ( email )

Canada

James Watmough

York University - Centre for Diseases Modeling (CDM) ( email )

Canada

Jude Dzevela Kong

York University - Centre for Diseases Modeling (CDM) ( email )

Canada

Iain Moyles

York University - Centre for Diseases Modeling (CDM)

Canada

Huaiping Zhu (Contact Author)

York University - Centre for Diseases Modeling (CDM)

Canada

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