Modeling COVID-19 Outbreaks in Long-Term Care Facilities Using an Agent-Based Modeling and Simulation Approach.

Ali Asgary,Mahdi Najafabadi,Hudson Blue,Zachary Mccarthy,Mohammad Ali Tofighi,Jianhong Wu,Adriano O Solis

doi:10.3390/ijerph19052635

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.

Highlights

The COVID-19 pandemic has passed through communities, affecting the most vulnerable people, especially the elderly [1]
The Long-term care facilities (LTCFs) typically have several residents living in close proximity inside a single building, giving a communicable disease such as COVID-19—which is transmitted by droplets—the opportunity to spread quickly among susceptible residents who are in close contact with an infected viral vector [27]
These parameters define how the disease spreads among individuals during the simulation. They are based on the parameters used in [21], which examined COVID-19 testing rates in schools using a similar agent-based modeling and simulation approach

Summary

Introduction

The COVID-19 pandemic has passed through communities, affecting the most vulnerable people, especially the elderly [1]. 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]. In Ontario, Canada, 82% of LTCF residents are 75 years old or above, and more than 50% are over 85 [30] These residents are at higher risk of hospitalization and death from COVID-19 [29]. The LTCFs typically have several residents living in close proximity inside a single building, giving a communicable disease such as COVID-19—which is transmitted by droplets—the opportunity to spread quickly among susceptible residents who are in close contact with an infected viral vector [27]

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