Mathematical Modeling and Analysis of COVID-19 pandemic in Nigeria

AbstractA novel Coronavirus (COVID-19), caused by SARS-CoV-2, emerged from the Wuhan city of China at the end of 2019, causing devastating public health and socio-economic burden around the world. In the absence of a safe and effective vaccine or antiviral for use in humans, control and mitigation efforts against COVID-19 are focussed on using non-pharmaceutical interventions (aimed at reducing community transmission of COVID-19), such as social (physical)-distancing, community lockdown, use of face masks in public, isolation and contact tracing of confirmed cases and quarantine of people suspected of being exposed to COVID-19. We developed a mathematical model for understanding the transmission dynamics and control of COVID-19 in Nigeria, one of the main epicenters of COVID-19 in Africa. Rigorous analysis of the Kermack-McKendrick-type compartmental epidemic model we developed, which takes the form of a deterministic system of nonlinear differential equations, reveal that the model has a continuum of disease-free equilibria which is locally-asymptotically stable whenever a certain epidemiological threshold, called the control reproduction (denoted by ), is less than unity. The epidemiological implication of this result is that the pandemic can be effectively controlled (or even eliminated) in Nigeria if the control strategies implemented can bring (and maintain) the epidemiological threshold () to a value less than unity. The model, which was parametrized using COVID-19 data published by Nigeria Centre for Disease Control (NCDC), was used to assess the community-wide impact of various control and mitigation strategies in the entire Nigerian nation, as well as in two states (Kano and Lagos) within the Nigerian federation and the Federal Capital Territory (FCT Abuja). It was shown that, for the worst-case scenario where social-distancing, lockdown and other community transmission reduction measures are not implemented, Nigeria would have recorded a devastatingly high COVID-19 mortality by April 2021 (in hundreds of thousands). It was, however, shown that COVID-19 can be effectively controlled using social-distancing measures provided its effectiveness level is at least moderate. Although the use of face masks in the public can significantly reduce COVID-19 in Nigeria, its use as a sole intervention strategy may fail to lead to the realistic elimination of the disease (since such elimination requires unrealistic high compliance in face mask usage in the public, in the range of 80% to 95%). COVID-19 elimination is feasible in both the entire Nigerian nation, and the States of Kano and Lagos, as well as the FCT, if the public face masks use strategy (using mask with moderate efficacy, and moderate compliance in its usage) is complemented with a social-distancing strategy. The lockdown measures implemented in Nigeria on March 30, 2020 need to be maintained for at least three to four months to lead to the effective containment of COVID-19 outbreaks in the country. Relaxing, or fully lifting, the lockdown measures sooner, in an effort to re-open the economy or the country, may trigger a deadly second wave of the pandemic.

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Benefits of integrated screening and vaccination for infection control

10.1101/2021.12.18.21268047 ◽

2021 ◽

Author(s):

Marie Jeanne Rabil ◽

Sait Tunc ◽

Douglas R. Bish ◽

Ebru K. Bish

Keyword(s):

Vaccination Coverage ◽

Vaccine Coverage ◽

Intervention Strategy ◽

College Campus ◽

Routine Screening ◽

Mitigation Strategies ◽

Disease Spread ◽

Effective Vaccine ◽

Model Parameters ◽

Worst Case

Importance. Screening and vaccination are essential in the fight against infectious diseases, but need to be integrated and customized based on community and disease characteristics. Objective. To develop effective screening and vaccination strategies, customized for a college campus, to reduce COVID-19 infections, hospitalizations, deaths, and peak hospitalizations. Design, Setting, and Participants. We construct a compartmental model of disease spread for vaccination and routine screening, and study the efficacy of four mitigation strategies (routine screening only, vaccination only, vaccination with partial routine screening, vaccination with full routine screening), and a no-intervention strategy. The study setting is a hypothetical college campus of 5,000 students and 455 faculty members, with 11 undetected, asymptotic SARS-CoV-2 infections at the start of an 80-day semester. For sensitivity analysis, we vary the screening frequency, daily vaccination rate, initial vaccination coverage, and screening and vaccination compliance; and consider three scenarios that represent low/medium/high transmission rates and test efficacy. Model parameters come from publicly available or published sources. Results. With low initial vaccination coverage, even aggressive vaccination and screening result in a high number of infections: 1,024/2,040 (1,532/1,773) with routine daily (every other day) screening of the unvaccinated; 275/895 with daily screening extended to the newly vaccinated in base- and worst-case scenarios, with reproduction numbers 4.75 and 6.75, respectively, representative of COVID-19 Delta variant. With the emergence of the Omicron variant, the reproduction number may increase and/or effective vaccine coverage may decrease if a booster shot is needed to maximize vaccine efficacy. Conclusion. Integrated vaccination and routine screening can allow for a safe opening of a college when initial vaccination coverage is sufficiently high. The interventions need to be customized considering the initial vaccination coverage, estimated compliance, screening and vaccination capacity, disease transmission and adverse outcome rates, and the number of infections/peak hospitalizations the college is willing to tolerate.

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Epidemiological modelling of the health and economic effects of COVID-19 control in Australia’s second wave

Journal of Public Health ◽

10.1007/s10389-021-01611-0 ◽

2021 ◽

Author(s):

R. Quentin Grafton ◽

John Parslow ◽

Tom Kompas ◽

Kathryn Glass ◽

Emily Banks

Keyword(s):

Public Health ◽

Health Outcomes ◽

Health Management ◽

Economic Effects ◽

Social Distancing ◽

The Public ◽

Long Duration ◽

Community Transmission ◽

Second Wave ◽

Detection Strategies

Abstract Background We investigated the public health and economy outcomes of different levels of social distancing to control a ‘second wave’ outbreak in Australia and identify implications for public health management of COVID-19. Methods Individual-based and compartment models were used to simulate the effects of different social distancing and detection strategies on Australian COVID-19 infections and the economy from March to July 2020. These models were used to evaluate the effects of different social distancing levels and the early relaxation of suppression measures, in terms of public health and economy outcomes. Results The models, fitted to observations up to July 2020, yielded projections consistent with subsequent cases and showed that better public health outcomes and lower economy costs occur when social distancing measures are more stringent, implemented earlier and implemented for a sufficiently long duration. Early relaxation of suppression results in worse public health outcomes and higher economy costs. Conclusions Better public health outcomes (reduced COVID-19 fatalities) are positively associated with lower economy costs and higher levels of social distancing; achieving zero community transmission lowers both public health and economy costs compared to allowing community transmission to continue; and early relaxation of social distancing increases both public health and economy costs.

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High national acceptance for COVID-19 contact tracing technologies in Taiwan (Preprint)

10.2196/preprints.31522 ◽

2021 ◽

Author(s):

Paul M. Garrett ◽

Yuwen Wang ◽

Joshua P. White ◽

Yoshihisa Kashima ◽

Simon Dennis ◽

...

Keyword(s):

Technology Acceptance ◽

Contact Tracing ◽

Virus Spread ◽

Security Measures ◽

Contributing Factors ◽

Privacy And Security ◽

Social Distancing ◽

The Public ◽

Privacy Measures ◽

Credible Intervals

BACKGROUND Governments worldwide have introduced COVID-19 tracing technologies. Taiwan, a world leader in controlling the virus’ spread, has introduced the Taiwan ‘Social Distancing App’ to facilitate COVID-19 contact tracing. However, for these technologies to be effective, they must be accepted and used by the public. OBJECTIVE Our study aimed to determine public acceptance for three hypothetical tracing technologies: a centralized Government App, a decentralized Bluetooth App (e.g., Taiwan’s Social Distancing App), and a Telecommunication tracing technology; and model what factors contributed to their acceptance. METHODS Four nationally representative surveys were conducted in April 2020 sampling 6,000 Taiwanese residents. Perceptions and impacts of COVID-19, government effectiveness, worldviews, and attitudes towards and acceptance of one-of-three hypothetical tracing technologies were assessed. RESULTS Technology acceptance was high across all hypothetical technologies (67% - 73%) and improved with additional privacy measures (82% - 88%). Bayesian modelling (using 95% highest density credible intervals) showed data sensitivity and perceived poor COVID-19 policy compliance inhibited technology acceptance. By contrast, technology benefits (e.g., returning to activities, reducing virus spread, lowering the likelihood of infection), higher education, and perceived technology privacy, security, and trust, were all contributing factors to overall acceptance. Bayesian ordinal probit models revealed higher COVID-19 concern for other people than for one’s self. CONCLUSIONS Taiwan is currently using a range of technologies to minimize the spread of COVID-19 as the country returns to normal economic and social activities. We observed high acceptance for COVID-19 tracing technologies among the Taiwanese public, a promising and necessary finding for the successful introduction of Taiwan’s new ‘Social Distancing App’. Policy makers may capitalize on this acceptance by focusing attention towards the App’s benefits, privacy and security measures, making the App’s privacy measures transparent to the public, and emphasizing App uptake and compliance among the public. CLINICALTRIAL Not applicable.

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COVID-19: Recent updates on SARS-CoV-2 and Preventing its Community Transmission in India by 21 Days Lockdown

Journal of Pure and Applied Microbiology ◽

10.22207/jpam.14.spl1.29 ◽

2020 ◽

Vol 14 (suppl 1) ◽

pp. 921-929

Author(s):

Satyajeet K. Pawar ◽

Shivaji T. Mohite

Keyword(s):

Hubei Province ◽

Hand Washing ◽

Contact Tracing ◽

Wuhan City ◽

Social Distancing ◽

First Case ◽

Rapid Spread ◽

Community Transmission ◽

Almost All

The current pandemic of COVID-19 has caused havoc all over world since its emergence and rapid spread. Within three months the virus SARS-CoV-2 which was isolated from pneumonia cases in Wuhan City, Hubei Province, China in late December 2019, has affected almost all countries. India reported its first case of COVID-19 from state of Kerala on January 30, 2020, a student returned from city of Wuhan. Till date in India the disease had affected 12759 patients with 420 deaths. With every passing day the mysterious virus is been uncovered with its unique characteristics enabling the researcher to unfold the various methods including hand washing and social distancing to curtail the pandemic. Measures like 21 days lockdown to certain extent are effective but considering asymptomatic spreaders, extended measured lockdowns will be useful in the long term war against COVID-19. Till the vaccine and therapeutic solutions are derived, answer to pandemic and SARS-CoV-2 lies in lockdown, social distancing, contact tracing and containment.

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Modelling the impact of reducing control measures on the COVID-19 pandemic in a low transmission setting

10.1101/2020.06.11.20127027 ◽

2020 ◽

Cited By ~ 1

Author(s):

Nick Scott ◽

Anna Palmer ◽

Dominic Delport ◽

Romesh Abeysuriya ◽

Robyn Stuart ◽

...

Keyword(s):

Public Transport ◽

Risk Mitigation ◽

Mitigation Strategies ◽

Control Measures ◽

Contact Tracing ◽

Policy Changes ◽

Low Transmission ◽

Transmission Setting ◽

Community Transmission ◽

The Impact

AbstractAimsWe assessed COVID-19 epidemic risks associated with relaxing a set of physical distancing restrictions in the state of Victoria, Australia – a setting with low community transmission – in line with a national framework that aims to balance sequential policy relaxations with longer-term public health and economic need.MethodsAn agent-based model, Covasim, was calibrated to the local COVID-19 epidemiological and policy environment. Contact networks were modelled to capture transmission risks in households, schools and workplaces, and a variety of community spaces (e.g. public transport, parks, bars, cafes/restaurants) and activities (e.g. community or professional sports, large events). Policy changes that could prevent or reduce transmission in specific locations (e.g. opening/closing businesses) were modelled in the context of interventions that included testing, contact tracing (including via a smartphone app), and quarantine.ResultsPolicy changes leading to the gathering of large, unstructured groups with unknown individuals (e.g. bars opening, increased public transport use) posed the greatest risk, while policy changes leading to smaller, structured gatherings with known individuals (e.g. small social gatherings) posed least risk. In the model, epidemic impact following some policy changes took more than two months to occur. Model outcomes support continuation of working from home policies to reduce public transport use, and risk mitigation strategies in the context of social venues opening, such as >30% population-uptake of a contact-tracing app, physical distancing policies within venues reducing transmissibility by >40%, or patron identification records being kept to enable >60% contact tracing.ConclusionsIn a low transmission setting, care should be taken to avoid lifting sequential COVID-19 policy restrictions within short time periods, as it could take more than two months to detect the consequences of any changes. These findings have implications for other settings with low community transmission where governments are beginning to lift restrictions.

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Cost Benefit Analysis of Limited Reopening Relative to a Herd Immunity Strategy or Shelter in Place for SARS-CoV-2 in the United States

10.1101/2020.06.26.20141044 ◽

2020 ◽

Cited By ~ 1

Author(s):

Robert B. Schonberger ◽

Yair J. Listokin ◽

Ian Ayres ◽

Reza Yaesoubi ◽

Zachary R. Shelley

Keyword(s):

United States ◽

Cost Effectiveness ◽

Herd Immunity ◽

The United States ◽

Mitigation Strategies ◽

United States Government ◽

Effective Vaccine ◽

Social Distancing ◽

Mortality Effect ◽

Life Years

ABSTRACTBackgroundFierce debate about the health and financial tradeoffs presented by different COVID-19 pandemic mitigation strategies highlights the need for rigorous quantitative evaluation of policy options.ObjectiveTo quantify the economic value of the costs and benefits of a policy of continued limited reopening with social distancing relative to alternative COVID-19 response strategies in the United States.DesignWe estimate the number and value of quality-adjusted life-years (QALY) gained from mortality averted, with a value of $125,000 per QALY, and compare these benefits to the associated costs in terms of plausible effects on US GDP under a policy of continued limited reopening with social distancing relative to a policy of full reopening toward herd immunity. Using the same QALY value assumptions, we further evaluate cost-effectiveness of a return to Shelter-in-Place relative to a policy of limited reopening.SettingUnited StatesMeasurementsQALY and cost as percent of GDP of limited reopening with continued social distancing relative to a strategy of full reopening aimed at achieving herd immunity; a limited reopening “budget” measured in the number of months before this strategy fails to demonstrate cost-effectiveness relative to a full reopening; a shelter-in-place “threshold” measured in the number of lives saved at which a month of sheltering in place demonstrates cost effectiveness relative to the limited reopening strategy.ResultsQALY benefits from mortality averted by continued social distancing and limited reopening relative to a policy of full reopening exceed projected GDP costs if an effective vaccine or therapeutic can be developed within 11.1 months from late May 2020. White House vaccine projections fall within this date, supporting a partial reopening strategy. One month of shelter-in-place restrictions provides QALY benefits from averted mortality that exceed the associated GDP costs relative to limited reopening if the restrictions prevent at least 154,586 additional COVID-19 deaths over the course of the pandemic. Current models of disease progression suggest that limited reopening will not cause this many additional deaths, again supporting a limited reopening strategy.LimitationLimited horizon of COVID-19 mortality projections; infection fatality ratio stable across strategies, ignoring both the potential for ICU overload to increase mortality and the deployment of partially effective therapeutics to decrease mortality; effect on GDP modeled as constant within a given phase of the pandemic; accounts for age and sex distribution of QALYs, but not effect of comorbidities; only considers impact from QALY lost due to mortality and from changes in GDP, excluding numerous other considerations, such as non-fatal COVID-19 morbidity, reduced quality of life caused by prolonged social distancing, or educational regression associated with prolonged school closures and restrictions.ConclusionsA limited reopening to achieve partial mitigation of COVID-19 is cost effective relative to a full reopening if an effective therapeutic or vaccine can be deployed within 11.1 months of late May 2020. One additional month of shelter-in-place restrictions should only be imposed if it saves at least 154,586 lives per month before the development of an effective therapeutic or vaccine relative to limited reopening.FundingThis work was supported in part by grant K01AI119603 from the National Institute of Allergy and Infectious Diseases (NIAID). This work does not necessarily represent the opinions of the NIAID, the NIH, or the United States Government.

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Containing Covid-19 outbreaks with spatially targeted short-term lockdowns and mass-testing

10.1101/2020.05.05.20092221 ◽

2020 ◽

Cited By ~ 1

Author(s):

Justin Alsing ◽

Thomas Kirk ◽

Naïri Usher ◽

Philip JD Crowley

Keyword(s):

Process Model ◽

Interaction Model ◽

Transmission Dynamics ◽

Contact Tracing ◽

Moderate Increase ◽

Mobility Patterns ◽

Social Distancing ◽

Targeted Interventions ◽

Community Transmission ◽

The Uk

ABSTRACTWe assess the efficacy of spatially targeted lockdown or mass-testing and case-isolation in individual communities, as a compliment to contact-tracing and social-distancing, for containing SARS-CoV-2 outbreaks. Using the UK as a case study, we construct a stochastic branching process model for the virus transmission, embedded on a network interaction model encoding mobility patterns in the UK. The network model is based on commuter data from the 2011 census, a catchment area model for schools, and a phenomenological model for mobility and interactions outside of work, school, and the home. We show that for outbreak scenarios where contact-tracing and moderate social distancing alone provide suppression but do not contain the spread, targeted lockdowns or mass-testing interventions at the level of individual communities (with just a few thousand inhabitants) can be effective at containing outbreaks. For spatially targeted mass-testing, a moderate increase in testing capacity would be required (typically < 40000 additional tests per day), while for local lockdowns we find that only a small fraction (typically < 0.1%) of the population needs to be locked down at any one time (assuming that one third of transmission occurs in the home, at work or school, and out in the wider community respectively). The efficacy of spatially targeted interventions is contingent on an appreciable fraction of transmission events occurring within (relative to across) communities. Confirming the efficacy of community-level interventions therefore calls for detailed investigation of spatial transmission patterns for SARS-CoV-2, accounting for sub-community-scale transmission dynamics, and changes in mobility patterns due to the presence of other containment measures (such as social distancing and travel restrictions).Disclaimer: We stress that this is a working paper where results are preliminary and subject to change. In particular, we note that the efficacy of spatially targeted interventions are sensitive to the relative proportions of intra-versus inter-community transmission (for a given definition of community boundaries), which in turn is sensitive to the assumptions about the transmission dynamics across different contexts. Whilst the assumptions made here about transmission across contexts are motivated, we are currently updating our model to make the estimated inter- and intra-community transmission rates as robust as possible, as well as running a comprehensive suite of sensitivity tests and different outbreak scenarios.

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Coronavirus Disease 2019: Community Risk Mitigation Strategies in China

Journal of Emergency Management and Disaster Communications ◽

10.1142/s2689980920400084 ◽

2020 ◽

Vol 01 (01) ◽

pp. 73-87

Author(s):

Benran Jiang ◽

Wei Li ◽

Ting Yuan

Keyword(s):

Risk Mitigation ◽

Mitigation Strategies ◽

Contact Tracing ◽

Targeted Prevention ◽

Risk Levels ◽

The Public ◽

Effective Contact ◽

Community Risk ◽

Risk Mitigation Strategies ◽

And Control

The COVID-19 pandemic has been a global health emergency. In the absence of effective pharmaceutical interventions and vaccine, long-term community risk mitigation strategies are crucial to prevent and control the resurgence of the epidemic in China. A multi-level, region-specific and dynamic approach has been applied to ensure early detection, quick response, effective contact tracing and management, and targeted prevention and control on the basis of risk levels. Science popularization of the public health measures in the community is also an important strategy to curb the risk of pandemic.

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Estimating Household Transmission of SARS-CoV-2

10.1101/2020.05.23.20111559 ◽

2020 ◽

Cited By ~ 8

Author(s):

Mihaela Curmei ◽

Andrew Ilyas ◽

Owain Evans ◽

Jacob Steinhardt

Keyword(s):

Attack Rate ◽

False Negative ◽

Policy Implications ◽

Contact Tracing ◽

Reliable Estimate ◽

False Negatives ◽

Social Distancing ◽

Household Transmission ◽

Contact Patterns ◽

Community Transmission

Introduction and GoalsSARS-CoV-2 is transmitted both in the community and within households. Social distancing and lockdowns reduce community transmission but do not directly address household transmission. We provide quantitative measures of household transmission based on empirical data, and estimate the contribution of households to overall spread. We highlight policy implications from our analysis of household transmission, and more generally, of changes in contact patterns under social distancing.MethodsWe investigate the household secondary attack rate (SAR) for SARS-CoV-2, as well as Rh, which is the average number of within-household infections caused by a single index case. We identify previous works that estimated the SAR. We correct these estimates based on the false-negative rate of PCR testing and the failure to test asymptomatics. Results are pooled by a hierarchical Bayesian random-effects model to provide a meta-analysis estimate of the SAR. We estimate Rh using results from population testing in Vo’, Italy and contact tracing data that we curate from Singapore. The code and data behind our analysis are publicly available1.ResultsWe identified nine studies of the household secondary attack rate. Our modeling suggests the SAR is heterogeneous across studies. The pooled central estimate of the SAR is 30% but with a posterior 95% credible interval of (0%, 67%) reflecting this heterogeneity. This corresponds to a posterior mean for the SAR of 30% (18%, 43%) and a standard deviation of 15% (9%, 27%). If results are not corrected for false negatives and asymptomatics, the pooled central estimate for the SAR is 20% (0%, 43%). From the same nine studies, we estimate Rh to be 0.47 (0.13, 0.77). Using contact tracing data from Singapore, we infer an Rh value of 0.32 (0.22, 0.42). Population testing data from Vo’ yields an Rh estimate of 0.37 (0.34, 0.40) after correcting for false negatives and asymptomatics.InterpretationOur estimates of Rh suggest that household transmission was a small fraction (5%-35%) of R before social distancing but a large fraction after (30%-55%). This suggests that household transmission may be an effective target for interventions. A remaining uncertainty is whether household infections actually contribute to further community transmission or are contained within households. This can be estimated given high-quality contact tracing data.More broadly, our study points to emerging contact patterns (i.e., increased time at home relative to the community) playing a role in transmission of SARS-CoV-2. We briefly highlight another instance of this phenomenon (differences in contact between essential workers and the rest of the population), provide coarse estimates of its effect on transmission, and discuss how future data could enable a more reliable estimate.

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Barriers in Social Distancing during Covid19 pandemic - Is a message for forced lockdown

Journal of Medical Research and Innovation ◽

10.32892/jmri.222 ◽

2020 ◽

Vol 4 (2) ◽

pp. e000222 ◽

Cited By ~ 1

Author(s):

Ibad Ur Rehman ◽

Hamza Rafique Khan ◽

Wafa E Zainab ◽

Areeba Ahmed ◽

Muhammad Danial Ishaq ◽

...

Keyword(s):

Preventive Measure ◽

Effective Vaccine ◽

Practical Implementation ◽

Theoretical Concepts ◽

Social Distancing ◽

The Public ◽

New Information ◽

Novel Coronavirus ◽

The Masses ◽

Incident Cases

The world currently faces the predicament of the fast-spreading COVID-19 which as of 21st April 2020 affects 210 countries over the globe. As the disease started spreading its shadow at an alarmingly rapid rate, new information about the novel coronavirus was extracted and it has been reported to be mainly transmitted directly from person-to-person, droplet spread by cough or sneezing or by fomites. Till an effective vaccine becomes available the most potent preventive measure that can be taken is for people to maintain distance and avoid gatherings. Importance of social distancing has been discussed on many forums and disseminated among the public but the problem arises when the practical implementation does not encompass the entirety of the theoretical concepts. Understanding the barriers that stand between applying social distance in community is imperative if authorities and public health sectors expect a substantial change in incident cases. It's imperative that measures should be taken to stop the spread of misinformation, and guide the masses regarding the importance of social distancing. Since the virus spreads by droplet transmission, so without these proper social distancing measures, the burden will increase and it will not be possible to put a stop to this pandemic.

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