Citation: Asgary, A.; Blue, H.; Solis,
A.O.; McCarthy, Z.; Najafabadi, M.;
Tofighi, M.A.; Wu, J. Modeling
COVID-19 Outbreaks in Long-Term
Care Facilities Using an Agent-Based
Modeling and Simulation Approach.
Int. J. Environ. Res. Public Health 2022,
19, 2635. https://doi.org/10.3390/
ijerph19052635
Academic Editors: Keun Ho Ryu and
Nipon Theera-Umpon
Received: 10 January 2022
Accepted: 20 February 2022
Published: 24 February 2022
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4.0/).
International Journal of
Environmental Research
and Public Health
Article
Modeling COVID-19 Outbreaks in Long-Term Care Facilities
Using an Agent-Based Modeling and Simulation Approach
Ali Asgary
1,
* , Hudson Blue
1,
*, Adriano O. Solis
2
, Zachary McCarthy
3
, Mahdi Najafabadi
4
,
Mohammad Ali Tofighi
4
and Jianhong Wu
3
1
Disaster and Emergency Management Area, School of Administrative Studies, York University,
Toronto, ON M3J 1P3, Canada
2
Decision Sciences Area, School of Administrative Studies, York University, Toronto, ON M3J 1P3, Canada;
asolis@yorku.ca
3
Laboratory for Industrial and Applied Mathematics (LIAM), Department of Mathematics and Statistics,
York University, Toronto, ON M3J 1P3, Canada; zjm@yorku.ca (Z.M.); wuji@yorku.ca (J.W.)
4
Advanced Disaster, Emergency, and Rapid Response Simulation (ADERSIM), York University,
Toronto, ON M3J 1P3, Canada; mirmahdi@yorku.ca (M.N.); tofighim@yorku.ca (M.A.T.)
* Correspondence: asgary@yorku.ca (A.A.); hblue@rogers.com (H.B.)
Abstract:
The elderly, especially those individuals with pre-existing health problems, have been
disproportionally at a higher risk during the COVID-19 pandemic. Residents of long-term care
facilities have been gravely affected by the pandemic and resident death numbers have been far
above those of the general population. To better understand how infectious diseases such as COVID-
19 can spread through long-term care facilities, we developed an agent-based simulation tool that
uses a contact matrix adapted from previous infection control research in these types of facilities.
This matrix accounts for the average distinct daily contacts between seven different agent types that
represent the roles of individuals in long-term care facilities. The simulation results were compared to
actual COVID-19 outbreaks in some of the long-term care facilities in Ontario, Canada. Our analysis
shows that this simulation tool is capable of predicting the number of resident deaths after 50 days
with a less than 0.1 variation in death rate. We modeled and predicted the effectiveness of infection
control measures by utilizing this simulation tool. We found that to reduce the number of resident
deaths, the effectiveness of personal protective equipment must be above 50%. We also found that
daily random COVID-19 tests for as low as less than 10% of a long-term care facility’s population will
reduce the number of resident deaths by over 75%. The results further show that combining several
infection control measures will lead to more effective outcomes.
Keywords:
COVID-19; long-term care facilities; agent-based modeling; disease modeling;
contact matrix
1. Introduction
The COVID-19 pandemic has passed through communities, affecting the most vul-
nerable people, especially the elderly [
1
]. Long-term care facilities (LTCFs) were hit hard
by the pandemic, resulting in a significant number of deaths [
2
]. LTCFs have high contact
environments with several high-risk individuals living very close to each other [
3
]. To
reduce the spread of COVID-19 within an LTCF, several measures were introduced in
addition to normal health and safety practices. These include stricter social distancing,
scheduled and random testing of facility residents and staff, as well as the use of personal
protective equipment (PPE) [
2
]. While these measures reduced the spread of COVID-19
infection, fatality rates in LTCFs remained at a higher level compared to the general fatality
rate [
2
]. This calls for a better understanding of the measures listed above in terms of their
capability to control the virus spread in an LTCF.
In the past couple of decades and prior to the onset of the COVID-19 pandemic,
agent-based modeling (ABM) has been used in a good number of infectious disease epi-
demiological studies [
4
]. The traditional equation-based epidemiological models in earlier
Int. J. Environ. Res. Public Health 2022, 19, 2635. https://doi.org/10.3390/ijerph19052635 https://www.mdpi.com/journal/ijerph
