A simple model for control of COVID-19 infections on an urban campus

A customized susceptible, exposed, infected, and recovered compartmental model is presented for describing the control of asymptomatic spread of COVID-19 infections on a residential, urban college campus embedded in a large urban community by using public health protocols, founded on surveillance testing, contact tracing, isolation, and quarantine. Analysis in the limit of low infection rates—a necessary condition for successful operation of the campus—yields expressions for controlling the infection and understanding the dynamics of infection spread. The number of expected cases on campus is proportional to the exogenous infection rate in the community and is decreased by more frequent testing and effective contact tracing. Simple expressions are presented for the dynamics of superspreader events and the impact of partial vaccination. The model results compare well with residential data from Boston University’s undergraduate population for fall 2020.

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Using the LIST model to Estimate the Effects of Contact Tracing on COVID-19 Endemic Equilibria in England and its Regions

10.1101/2020.06.11.20128611 ◽

2020 ◽

Author(s):

Rosalyn J. Moran ◽

Alexander J. Billig ◽

Maell Cullen ◽

Adeel Razi ◽

Jean Daunizeau ◽

...

Keyword(s):

Endemic Equilibrium ◽

Contact Tracing ◽

Model Parameters ◽

Infection Rates ◽

Stable States ◽

Medium Term ◽

The Stability ◽

Lower Death Rate ◽

The Impact ◽

List Model

AbstractGovernments across Europe are preparing for the emergence from lockdown, in phases, to prevent a resurgence in cases of COVID-19. Along with social distancing (SD) measures, contact tracing – find, track, trace and isolate (FTTI) policies are also being implemented. Here, we investigate FTTI policies in terms of their impact on the endemic equilibrium. We used a generative model – the dynamic causal ‘Location’, ‘Infection’, ‘Symptom’ and ‘Testing’ (LIST) model to identify testing, tracing, and quarantine requirements. We optimised LIST model parameters based on time series of daily reported cases and deaths of COVID-19 in England— and based upon reported cases in the nine regions of England and in all 150 upper tier local authorities. Using these optimised parameters, we forecasted infection rates and the impact of FTTI for each area—national, regional, and local. Predicting data from early June 2020, we find that under conditions of medium-term immunity, a ‘40%’ FTTI policy (or greater), could reach a distinct endemic equilibrium that produces a significantly lower death rate and a decrease in ICU occupancy. Considering regions of England in isolation, some regions could substantially reduce death rates with 20% efficacy. We characterise the accompanying endemic equilibria in terms of dynamical stability, observing bifurcation patterns whereby relatively small increases in FTTI efficacy result in stable states with reduced overall morbidity and mortality. These analyses suggest that FTTI will not only save lives, even if only partially effective, and could underwrite the stability of any endemic steady-state we manage to attain.

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Possible fates of the dispersion of SARS-COV-2 in the Mexican context

10.1101/2020.07.15.20154526 ◽

2020 ◽

Author(s):

Ivan Santamaria-Holek ◽

Victor Castano

Keyword(s):

Time Evolution ◽

Compartmental Model ◽

Social Policies ◽

Infection Rates ◽

Conceptual Tool ◽

Epidemiological Research ◽

Social Distancing ◽

The Impact

The determination of the adequate time for house confinement and when social distancing restrictions should end are now two of the main challenges that any country has to face in an effective battle against. The possibility of a new outbreak of the pandemic and how to avoid it is, nowadays, one of the primary objectives of epidemiological research. In this work, we go deep in this subject by presenting an innovative compartmental model, that explicitly introduces the number of active cases, and employing it as a conceptual tool to explore the possible fates of the dispersion of SARS-COV-2 in the Mexican context. We incorporated the impact of starting, inattention, and end of restrictive social policies on the time evolution of the pandemics via time-in-run corrections to the infection rates. The magnitude and impact on the epidemic due to post-social restrictive policies are also studied. The scenarios generated by the model can help authorities to determine an adequate time and population load that may be allowed to reassume normal activities.

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Assessing the impact of varying levels of case detection and contact tracing on COVID-19 transmission in Canada during lifting of restrictive closures using a dynamic compartmental model

Canada Communicable Disease Report ◽

10.14745/ccdr.v46i1112a08 ◽

2020 ◽

Vol 46 (1112) ◽

pp. 409-421

Author(s):

Antoinette Ludwig ◽

Philippe Berthiaume ◽

Heather Orpana ◽

Claude Nadeau ◽

Maikol Diasparra ◽

...

Keyword(s):

Compartmental Model ◽

Contact Tracing ◽

Case Detection ◽

The Impact

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Real-Time Digital Contact Tracing: Development of a System to Control COVID-19 Outbreaks in Nursing Homes and Long-Term Care Facilities

JMIR Public Health and Surveillance ◽

10.2196/20828 ◽

2020 ◽

Vol 6 (3) ◽

pp. e20828 ◽

Cited By ~ 1

Author(s):

Gerald Wilmink ◽

Ilyssa Summer ◽

David Marsyla ◽

Subhashree Sukhu ◽

Jeffrey Grote ◽

...

Keyword(s):

Nursing Homes ◽

Compartmental Model ◽

Long Term Care ◽

Contact Tracing ◽

Term Care ◽

Viral Spread ◽

Effective Manner ◽

Conventional Methods ◽

The Impact

Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can spread rapidly in nursing homes and long-term care (LTC) facilities. Symptoms-based screening and manual contact tracing have limitations that render them ineffective for containing the viral spread in LTC facilities. Symptoms-based screening alone cannot identify asymptomatic people who are infected, and the viral spread is too fast in confined living quarters to be contained by slow manual contact tracing processes. Objective We describe the development of a digital contact tracing system that LTC facilities can use to rapidly identify and contain asymptomatic and symptomatic SARS-CoV-2 infected contacts. A compartmental model was also developed to simulate disease transmission dynamics and to assess system performance versus conventional methods. Methods We developed a compartmental model parameterized specifically to assess the coronavirus disease (COVID-19) transmission in LTC facilities. The model was used to quantify the impact of asymptomatic transmission and to assess the performance of several intervention groups to control outbreaks: no intervention, symptom mapping, polymerase chain reaction testing, and manual and digital contact tracing. Results Our digital contact tracing system allows users to rapidly identify and then isolate close contacts, store and track infection data in a respiratory line listing tool, and identify contaminated rooms. Our simulation results indicate that the speed and efficiency of digital contact tracing contributed to superior control performance, yielding up to 52% fewer cases than conventional methods. Conclusions Digital contact tracing systems show promise as an effective tool to control COVID-19 outbreaks in LTC facilities. As facilities prepare to relax restrictions and reopen to outside visitors, such tools will allow them to do so in a surgical, cost-effective manner that controls outbreaks while safely giving residents back the life they once had before this pandemic hit.

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Excess Risk of COVID-19 to University Populations Resulting from In-Person Sporting Events

10.1101/2020.09.27.20202499 ◽

2020 ◽

Author(s):

Stephanie S Johnson ◽

Katelin C Jackson ◽

Matthew S Mietchen ◽

Samir Sbai ◽

Elissa J Schwartz ◽

...

Keyword(s):

Parameter Uncertainty ◽

Compartmental Model ◽

College Campus ◽

Sporting Events ◽

Campus Community ◽

Wide Range ◽

High Prevalence ◽

Low Prevalence ◽

The University ◽

The Impact

Background: One of the consequences of COVID-19 has been the cancelation of in-person collegiate sporting events. We explore the impact of having in-person sports on COVID-19 transmission on a college campus, specifically the excess cases within the campus community can be anticipated. Methods: Using a stochastic compartmental model representing the interactions between the university community, we model the impact of transient influxes of visitors attending sporting events and ancillary activities (bars, dining out, etc.). We consider a number of scenarios, varying the extent to which visitors interact with the campus, the number of infectious visitors, and the extent to which the campus has controlled COVID-19 absent events. We also conducted a sensitivity analysis, exploring the model's outcomes over a wide range of uncertainty. Results: Events caused an increase in the number of cases among the campus community, ranging from a 25% increase in a scenario where the campus already had an uncontrolled COVID-19 outbreak and visitors had a low prevalence of COVID-19 and mixed lightly with the campus community to an 822% increase where the campus had controlled their COVID-19 outbreak and visitors had both a high prevalence of COVID-19 and mixed heavily with the campus community. The model was insensitive to parameter uncertainty, save for the duration a symptomatic individual was infectious. Conclusion: In-person sporting events represent a threat to the health of the campus community. This is the case even in circumstances where COVID-19 seems controlled both on-campus and among the larger population visitors are drawn from.

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Real-Time Digital Contact Tracing: Development of a System to Control COVID-19 Outbreaks in Nursing Homes and Long-Term Care Facilities (Preprint)

10.2196/preprints.20828 ◽

2020 ◽

Author(s):

Gerald Wilmink ◽

Ilyssa Summer ◽

David Marsyla ◽

Subhashree Sukhu ◽

Jeffrey Grote ◽

...

Keyword(s):

Nursing Homes ◽

Compartmental Model ◽

Long Term Care ◽

Contact Tracing ◽

Term Care ◽

Viral Spread ◽

Effective Manner ◽

Conventional Methods ◽

The Impact

BACKGROUND Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can spread rapidly in nursing homes and long-term care (LTC) facilities. Symptoms-based screening and manual contact tracing have limitations that render them ineffective for containing the viral spread in LTC facilities. Symptoms-based screening alone cannot identify asymptomatic people who are infected, and the viral spread is too fast in confined living quarters to be contained by slow manual contact tracing processes. OBJECTIVE We describe the development of a digital contact tracing system that LTC facilities can use to rapidly identify and contain asymptomatic and symptomatic SARS-CoV-2 infected contacts. A compartmental model was also developed to simulate disease transmission dynamics and to assess system performance versus conventional methods. METHODS We developed a compartmental model parameterized specifically to assess the coronavirus disease (COVID-19) transmission in LTC facilities. The model was used to quantify the impact of asymptomatic transmission and to assess the performance of several intervention groups to control outbreaks: no intervention, symptom mapping, polymerase chain reaction testing, and manual and digital contact tracing. RESULTS Our digital contact tracing system allows users to rapidly identify and then isolate close contacts, store and track infection data in a respiratory line listing tool, and identify contaminated rooms. Our simulation results indicate that the speed and efficiency of digital contact tracing contributed to superior control performance, yielding up to 52% fewer cases than conventional methods. CONCLUSIONS Digital contact tracing systems show promise as an effective tool to control COVID-19 outbreaks in LTC facilities. As facilities prepare to relax restrictions and reopen to outside visitors, such tools will allow them to do so in a surgical, cost-effective manner that controls outbreaks while safely giving residents back the life they once had before this pandemic hit.

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The Impact of COVID-19 Testing on College Campuses

10.1101/2021.08.16.21262153 ◽

2021 ◽

Author(s):

Zhuoting Yu ◽

Akane B. Fujimoto ◽

Pinar Keskinocak ◽

Julie L Swann

Keyword(s):

Attack Rate ◽

Compartmental Model ◽

College Campuses ◽

College Campus ◽

Polymerase Chain ◽

Antigen Tests ◽

The Impact ◽

Antigen Testing ◽

Testing Protocols ◽

Partial Implementation

Background: After moving instruction online for more than a year, many colleges and universities are preparing to reopen and offering fully in-person classes for the Fall 2021 semester. In this paper, we study the impact of weekly testing protocols on college campuses. Methods: An extended susceptible-infectious-removed (SIR) compartmental model was used to simulate COVID-19 spread on a college campus setting. Seven scenarios were evaluated which considered polymerase chain reaction (PCR) and rapid antigen testing kits available at various levels of supply. The infection attack rate (IAR), the number of infections, and the number of tests utilized by the end of the simulation semester are reported and compared. Results: Weekly testing significantly reduces the number of infections compared to when testing is not available. The use of PCR tests results in the lowest infection attack rate and the total number of cases; however, using rapid antigen tests with higher coverage is more effective than using PCR tests with lower coverage. Conclusions: The implementation of COVID-19 testing protocols should be considered and evaluated as using testing allows for identification and isolation of cases which reduces the spread of COVID-19 on college campuses. Even if testing capacity is limited, its partial implementation can be beneficial.

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ECONOMIC ASSESSMENT OF THE MARKETING STRATEGY OF MUNICIPAL TRANSPORT

HERALD of Khmelnytskyi national university ◽

10.31891/2307-5740-2020-288-6-37 ◽

2020 ◽

Vol 288 (6) ◽

pp. 221-229

Author(s):

V. CHERNII ◽

Keyword(s):

Marketing Strategy ◽

Economic Assessment ◽

Marketing Strategies ◽

Point Of View ◽

Necessary Condition ◽

Successful Operation ◽

Pricing Policy ◽

Business Course ◽

Environmental Relations ◽

The Impact

Increasing globalization is leading to increased competition among businesses, which need to pay more attention to the needs of markets and customers. From the point of view of efficiency of activity of the enterprise it means increase of a role of marketing strategies of the enterprise. Despite the fact that the company is the main economic unit of the country, the problems of enterprise marketing are not given due attention both from a theoretical and practical point of view. The main conclusion based on the results of the analysis of publications is that the issues of the impact of economic analysis and evaluation of the effectiveness of marketing strategy in municipal transport enterprises are absent. The purpose of the article is to analyze the existing tools for conducting an economic assessment of the marketing strategy implemented at municipal transport enterprises. Quantifying the effectiveness of a system requires that it be described by a set of criteria. The choice of criteria is not a trivial task, because the system of a marketing enterprise is multifaceted. All these aspects should be turned into criteria. To do this, the system should be classified, ie grouped by their common features. Analysis of the literature on the problem shows that there are a large number of different classifications. This variation can be explained by the fact that the classification uses different characteristics of the system, such as the nature of the system, its management, the type of relationships between components, general characteristics of the system, relationship with the goal, complexity, variability, implementation, environmental relations, mathematical models used to describe the system, physical and other characteristics, level of organization, etc. Implementation of an effective marketing policy of municipal transport enterprises is a necessary condition for their successful operation, regardless of the size of the business. Carefully designed marketing strategies not only optimize the process of updating services, pricing policy, but also determine the business course of the enterprise. Ukrainian enterprises are actively implementing marketing technologies, although there are a number of difficulties for municipal transport enterprises that hinder this process.

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Possible fates of the spread of SARS-CoV-2 in the Mexican context

Royal Society Open Science ◽

10.1098/rsos.200886 ◽

2020 ◽

Vol 7 (9) ◽

pp. 200886

Author(s):

I. Santamaría-Holek ◽

V. Castaño

Keyword(s):

Time Evolution ◽

Compartmental Model ◽

Time Dependent ◽

Social Policies ◽

Infection Rates ◽

Conceptual Tool ◽

Epidemiological Research ◽

Social Distancing ◽

The Impact

The determination of the adequate time for house confinement and when social distancing restrictions should end are now two of the main challenges that any country has to face in an ongoing battle against SARS-CoV-2. The possibility of a new outbreak of the pandemic and how to avoid it is, nowadays, one of the primary objectives of epidemiological research. In this work, we present an innovative compartmental model that explicitly introduces the number of active cases, and employ it as a conceptual tool to explore the possible fates of the spread of SARS-CoV-2 in the Mexican context. We incorporated the impact of starting, inattention and end of restrictive social policies on the pandemic’s time evolution via time-dependent corrections to the infection rates. The magnitude and impact on the epidemic due to post-social restrictive policies are also studied. The scenarios generated by the model could help authorities determine an adequate time and population load that may be allowed to reassume normal activities.

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Excess Risk of COVID-19 to University Populations Resulting from In-Person Sporting Events

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18168260 ◽

2021 ◽

Vol 18 (16) ◽

pp. 8260

Author(s):

Stephanie S. Johnson ◽

Katelin C. Jackson ◽

Matthew S. Mietchen ◽

Samir Sbai ◽

Elissa J. Schwartz ◽

...

Keyword(s):

Parameter Uncertainty ◽

Compartmental Model ◽

Global Sensitivity Analysis ◽

College Campus ◽

Sporting Events ◽

Campus Community ◽

High Prevalence ◽

Low Prevalence ◽

The University ◽

The Impact

Background: One of the consequences of COVID-19 has been the cancelation of collegiate sporting events. We explore the impact of sports on COVID-19 transmission on a college campus. Methods: Using a compartmental model representing the university, we model the impact of influxes of 10,000 visitors attending events and ancillary activities (dining out, visiting family, shopping, etc.) on 20,000 students. We vary the extent visitors interact with the campus, the number of infectious visitors, and the extent to which the campus has controlled COVID-19 absent events. We also conduct a global sensitivity analysis. Results: Events caused an increase in the number of cases ranging from a 25% increase when the campus already had an uncontrolled COVID-19 outbreak and visitors had a low prevalence of COVID-19 and mixed lightly with the campus community to an 822% increase where the campus had controlled their COVID-19 outbreak and visitors had both a high prevalence of COVID-19 and mixed heavily with the campus community. The model was insensitive to parameter uncertainty, save for the duration a symptomatic individual was infectious. Conclusion: Sporting events represent a threat to the health of the campus community. This is the case even in circumstances where COVID-19 seems controlled both on-campus and among the general population.

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