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Montcho Y, Dako S, Salako VK, Tovissodé CF, Wolkewitz M, Glèlè Kakaï R. Assessing marginal effects of non-pharmaceutical interventions on the transmission of SARS-CoV-2 across Africa: a hybrid modeling study. MATHEMATICAL MEDICINE AND BIOLOGY : A JOURNAL OF THE IMA 2024; 41:225-249. [PMID: 39083019 DOI: 10.1093/imammb/dqae013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 07/19/2024] [Accepted: 07/30/2024] [Indexed: 09/18/2024]
Abstract
Since 2019, a new strain of coronavirus has challenged global health systems. Due its fragile healthcare systems, Africa was predicted to be the most affected continent. However, past experiences of African countries with epidemics and other factors, including actions taken by governments, have contributed to reducing the spread of SARS-CoV-2. This study aims to assess the marginal impact of non-pharmaceutical interventions in fifteen African countries during the pre-vaccination period. To describe the transmission dynamics and control of SARS-CoV-2 spread, an extended time-dependent SEIR model was used. The transmission rate of each infectious stage was obtained using a logistic model with NPI intensity as a covariate. The results revealed that the effects of NPIs varied between countries. Overall, restrictive measures related to assembly had, in most countries, the largest reducing effects on the pre-symptomatic and mild transmission, while the transmission by severe individuals is influenced by privacy measures (more than $10\%$). Countries should develop efficient alternatives to assembly restrictions to preserve the economic sector. This involves e.g. training in digital tools and strengthening digital infrastructures.
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Affiliation(s)
- Yvette Montcho
- Laboratoire de Biomathématiques et d'Estimations Forestières, Universty of Abomey-Calavi, 04 BP 1525, Cotonou, Benin
| | - Sidoine Dako
- Laboratoire de Biomathématiques et d'Estimations Forestières, Universty of Abomey-Calavi, 04 BP 1525, Cotonou, Benin
| | - Valère Kolawole Salako
- Laboratoire de Biomathématiques et d'Estimations Forestières, Universty of Abomey-Calavi, 04 BP 1525, Cotonou, Benin
| | - Chénangnon Frédéric Tovissodé
- Laboratoire de Biomathématiques et d'Estimations Forestières, Universty of Abomey-Calavi, 04 BP 1525, Cotonou, Benin
| | - Martin Wolkewitz
- Institute of Medical Biometry and Statistics, Faculty of Medicine and Medical Center, University of Freiburg, 79104, Freiburg, Germany
| | - Romain Glèlè Kakaï
- Laboratoire de Biomathématiques et d'Estimations Forestières, Universty of Abomey-Calavi, 04 BP 1525, Cotonou, Benin
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Yang C, Li Q, Zhao Z, Chen Z, Guo H, Huang D, Yin W. COVID-19 prevention and control effect of non-pharmaceutical interventions-fuzzy-sets qualitative comparative analysis based on 69 countries in the world. Front Public Health 2024; 12:1419109. [PMID: 39131571 PMCID: PMC11310030 DOI: 10.3389/fpubh.2024.1419109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Accepted: 07/10/2024] [Indexed: 08/13/2024] Open
Abstract
Introduction Coronavirus disease 2019 occurred unexpectedly in late December 2019, it was difficult to immediately develop an effective vaccine or propose targeted medical interventions in the early stages of the outbreak. At this point, non-pharmaceutical interventions (NPIs) are essential components of the public health response to COVID-19. How to combine different NPIs in the early stages of an outbreak to control the spread of epidemics and ensure that the policy combination does not incur high socio-economic costs became the focus of this study. Methods We mainly used the fuzzy set qualitative comparative analysis to assess the impact of different combinations of NPIs on the effectiveness of control in the COVID-19 pandemic early stage, using open datasets containing case numbers, country populations and policy responses. Results We showed that the configuration of high morbidity results includes one, which is the combination of non-strict face covering, social isolation and travel restrictions. The configuration of non-high morbidity results includes three, one is strict mask wearing measures, which alone constitute sufficient conditions for interpreting the results; the second is strict testing and contact tracing, social isolation; the third is strict testing and contact tracing, travel restriction. The results of the robustness test showed that the number, components and consistency of the configurations have not changed after changing the minimum case frequency, which proved that the analysis results are reliable. Conclusion In the early stages of the epidemic, the causes of high morbidity are not symmetrical with the causes of non-high morbidity. Strict face covering is the most basic measure required to prevent and control epidemics, and the combination of non-strict face covering and containment is the most important factor leading to poor prevention and control, and the combination of strict containment and proactive pursuit is the way to achieve superior prevention and control, timely and proactive containment strategies have better prevention and control, and should mobilize the public to cooperate.
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Affiliation(s)
- Chunxiao Yang
- School of Public Health, Shandong Second Medical University, Weifang, Shandong, China
| | - Qiusha Li
- School of Public Health, Shandong Second Medical University, Weifang, Shandong, China
| | - Zixuan Zhao
- School of Public Health, Shandong Second Medical University, Weifang, Shandong, China
| | - Zhongming Chen
- School of Management, Shandong Second Medical University, Weifang, Shandong, China
| | - Hongwei Guo
- School of Management, Shandong Second Medical University, Weifang, Shandong, China
| | - Dongmei Huang
- School of Management, Shandong Second Medical University, Weifang, Shandong, China
| | - Wenqiang Yin
- School of Management, Shandong Second Medical University, Weifang, Shandong, China
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Krauland MG, Roberts MS. Modeling the Impact of COVID-19 Mitigation Strategies in Pennsylvania, USA. MDM Policy Pract 2024; 9:23814683241260744. [PMID: 38911124 PMCID: PMC11191394 DOI: 10.1177/23814683241260744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 05/09/2024] [Indexed: 06/25/2024] Open
Abstract
Purpose. To estimate the impact on mortality of nonpharmaceutical interventions (NPIs) implemented early in the COVID-19 pandemic. Methods. We implemented an agent-based modified SEIR model of COVID-19, calibrated to match death numbers reported in Pennsylvania from January 2020 to April 2021 and including representations of NPIs implemented in Pennsylvania. To investigate the impact of these strategies, we ran the calibrated model with no interventions and with varying combinations, timings, and levels of interventions. Results. The model closely replicated death outcomes data for Pennsylvania. Without NPIs, deaths in the early months of the pandemic were estimated to be much higher (67,718 deaths compared to actual 6,969). Voluntary interventions alone were relatively ineffective at decreasing mortality. Delaying implementation of interventions led to higher deaths (∼9,000 more deaths with just a 1-week delay). School closure was insufficient as a single intervention but was an important part of a combined intervention strategy. Conclusions. NPIs were effective at reducing deaths early in the COVID-19 pandemic. Agent-based models can incorporate substantial detail on infectious disease spread and the impact of mitigations. Policy Implications. The model supports the importance and effectiveness of NPIs to decrease morbidity from respiratory pathogens. This is particularly important for emerging pathogens for which no vaccines or treatments exist, but such strategies are applicable to a variety of respiratory pathogens. Highlights Nonpharmaceutical interventions were used extensively during the early period of the COVID-19 pandemic, but their use has remained controversial.Agent-based modeling of the impact of these mitigation strategies early in the COVID-19 pandemic supports the effectiveness of nonpharmaceutical interventions at decreasing mortality.Since such interventions are not specific to a particular pathogen, they can be used to protect against any respiratory pathogen, known or emerging. They can be applied rapidly when conditions warrant.
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Affiliation(s)
- Mary G. Krauland
- Department of Health Policy and Management, School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
- Public Health Dynamics Laboratory, School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mark S. Roberts
- Department of Health Policy and Management, School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
- Public Health Dynamics Laboratory, School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
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Dudley L, Couper I, Kannangarage NW, Naidoo S, Ribas CR, Koller TS, Young T. COVID-19 preparedness and response in rural and remote areas: A scoping review. PLOS GLOBAL PUBLIC HEALTH 2023; 3:e0002602. [PMID: 37967067 PMCID: PMC10651055 DOI: 10.1371/journal.pgph.0002602] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 10/23/2023] [Indexed: 11/17/2023]
Abstract
This scoping review used the Arksey and O'Malley approach to explore COVID-19 preparedness and response in rural and remote areas to identify lessons to inform future health preparedness and response planning. A search of scientific and grey literature for rural COVID-19 preparedness and responses identified 5 668 articles published between 2019 and early 2022. A total of 293 articles were included, of which 160 (54.5%) were from high income countries and 106 (36.2%) from middle income countries. Studies focused mostly on the Maintenance of Essential Health Services (63; 21.5%), Surveillance, epidemiological investigation, contact tracing and adjustment of public health and social measures (60; 20.5%), Coordination and Planning (32; 10.9%); Case Management (30; 10.2%), Social Determinants of Health (29; 10%) and Risk Communication (22; 7.5%). Rural health systems were less prepared and national COVID-19 responses were often not adequately tailored to rural areas. Promising COVID-19 responses involved local leaders and communities, were collaborative and multisectoral, and engaged local cultures. Non-pharmaceutical interventions were applied less, support for access to water and sanitation at scale was weak, and more targeted approaches to the isolation of cases and quarantine of contacts were preferable to blanket lockdowns. Rural pharmacists, community health workers and agricultural extension workers assisted in overcoming shortages of health professionals. Vaccination coverage was hindered by weaker rural health systems. Digital technology enabled better coordination, communication, and access to health services, yet for some was inaccessible. Rural livelihoods and food security were affected through disruptions to local labour markets, farm produce markets and input supply chains. Important lessons include the need for rural proofing national health preparedness and response and optimizing synergies between top-down planning with localised planning and coordination. Equity-oriented rural health systems strengthening and action on rural social determinants is essential to better prepare for and respond to future outbreaks.
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Affiliation(s)
- Lilian Dudley
- Division of Health Systems and Public Health, Department of Global Health, Stellenbosch University, Cape Town, South Africa
| | - Ian Couper
- Ukwanda Centre for Rural Health, Department of Global Health, Stellenbosch University, Cape Town, South Africa
| | | | - Selvan Naidoo
- Ukwanda Centre for Rural Health, Department of Global Health, Stellenbosch University, Cape Town, South Africa
| | - Clara Rodriguez Ribas
- Health Emergencies Program, World Health Organisation, Headquarters, Geneva, Switzerland
- Universitat Pompeu Fabra, Barcelona, Spain
| | - Theadora Swift Koller
- Department for Gender, Equity and Human Rights, Director General’s Office, World Health Organization, Headquarters, Geneva, Switzerland
| | - Taryn Young
- Division of Epidemiology and Biostatistics, Department of Global Health, Stellenbosch University, Cape Town, South Africa
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Montcho Y, Nalwanga R, Azokpota P, Doumatè JT, Lokonon BE, Salako VK, Wolkewitz M, Glèlè Kakaï R. Assessing the Impact of Vaccination on the Dynamics of COVID-19 in Africa: A Mathematical Modeling Study. Vaccines (Basel) 2023; 11:vaccines11040857. [PMID: 37112769 PMCID: PMC10144609 DOI: 10.3390/vaccines11040857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Several effective COVID-19 vaccines are administered to combat the COVID-19 pandemic globally. In most African countries, there is a comparatively limited deployment of vaccination programs. In this work, we develop a mathematical compartmental model to assess the impact of vaccination programs on curtailing the burden of COVID-19 in eight African countries considering SARS-CoV-2 cumulative case data for each country for the third wave of the COVID-19 pandemic. The model stratifies the total population into two subgroups based on individual vaccination status. We use the detection and death rates ratios between vaccinated and unvaccinated individuals to quantify the vaccine's effectiveness in reducing new COVID-19 infections and death, respectively. Additionally, we perform a numerical sensitivity analysis to assess the combined impact of vaccination and reduction in the SARS-CoV-2 transmission due to control measures on the control reproduction number (Rc). Our results reveal that on average, at least 60% of the population in each considered African country should be vaccinated to curtail the pandemic (lower the Rc below one). Moreover, lower values of Rc are possible even when there is a low (10%) or moderate (30%) reduction in the SARS-CoV-2 transmission rate due to NPIs. Combining vaccination programs with various levels of reduction in the transmission rate due to NPI aids in curtailing the pandemic. Additionally, this study shows that vaccination significantly reduces the severity of the disease and death rates despite low efficacy against COVID-19 infections. The African governments need to design vaccination strategies that increase vaccine uptake, such as an incentive-based approach.
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Affiliation(s)
- Yvette Montcho
- Laboratoire de Biomathématiques et d'Estimations Forestières, Université d'Abomey-Calavi, Cotonou 04 BP 1525, Benin
| | - Robinah Nalwanga
- Laboratoire de Biomathématiques et d'Estimations Forestières, Université d'Abomey-Calavi, Cotonou 04 BP 1525, Benin
| | - Paustella Azokpota
- Laboratoire de Biomathématiques et d'Estimations Forestières, Université d'Abomey-Calavi, Cotonou 04 BP 1525, Benin
| | - Jonas Têlé Doumatè
- Laboratoire de Biomathématiques et d'Estimations Forestières, Université d'Abomey-Calavi, Cotonou 04 BP 1525, Benin
- Faculté des Sciences et Techniques, Université d'Abomey-Calavi, Abomey-Calavi, Cotonou 01 BP 526, Benin
| | - Bruno Enagnon Lokonon
- Laboratoire de Biomathématiques et d'Estimations Forestières, Université d'Abomey-Calavi, Cotonou 04 BP 1525, Benin
| | - Valère Kolawole Salako
- Laboratoire de Biomathématiques et d'Estimations Forestières, Université d'Abomey-Calavi, Cotonou 04 BP 1525, Benin
| | - Martin Wolkewitz
- Institute of Medical Biometry and Statistics, Faculty of Medicine and Medical Center, University of Freiburg, 79104 Freiburg, Germany
| | - Romain Glèlè Kakaï
- Laboratoire de Biomathématiques et d'Estimations Forestières, Université d'Abomey-Calavi, Cotonou 04 BP 1525, Benin
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The effect of self-esteem on the spread of a pandemic. A cross-country analysis of the role played by self-esteem in the spread of the COVID-19 pandemic. Soc Sci Med 2023; 324:115866. [PMID: 37015169 PMCID: PMC10030268 DOI: 10.1016/j.socscimed.2023.115866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 02/23/2023] [Accepted: 03/20/2023] [Indexed: 03/24/2023]
Abstract
Extant research on COVID-19 suggests that many socio-economic determinants, by affecting personal behavior, have influenced the evolution of the pandemic. In this paper we study the role played in this regard by average levels of self-esteem in the public. There are reasons to believe that both low and very levels of self-esteem may have an effect on the spread of COVID-19, for opposite reasons. On the one hand, people with low self-esteem may not worry enough to behave in the way recommended (and prescribed, through non-pharmaceutical interventions) by the authorities; people with very high self-esteem, on the other hand, may be over-confident and fail to follow the prescriptions, believing that they do not need them. In this study we test this hypothesis by means of a quantitative cross-country analysis, using a hybrid model and the Rosenberg self-esteem scale. Our results suggest the existence of a U-shaped relationship between the trend of COVID-19 and average levels of self-esteem in a country.
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Al-Bazi A, Madi F, Monshar AA, Eliya Y, Adediran T, Khudir KA. Modelling the impact of non-pharmaceutical interventions on COVID-19 exposure in closed-environments using agent-based modelling. INTERNATIONAL JOURNAL OF HEALTHCARE MANAGEMENT 2023. [DOI: 10.1080/20479700.2023.2189555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Affiliation(s)
- Ammar Al-Bazi
- Aston Business School, Aston University, Birmingham, UK
| | - Faris Madi
- Faculty of Engineering, Environment and Computing, Coventry University, Coventry, UK
| | | | - Yousif Eliya
- Department of Health Research Methods, Evidence & Impact, Health Sciences Centre, McMaster University, Hamilton, Canada
| | - Tunde Adediran
- Faculty of Engineering, Environment and Computing, Coventry University, Coventry, UK
| | - Khaled Al Khudir
- Faculty of Engineering, Environment and Computing, Coventry University, Coventry, UK
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Luo W, Liu Z, Zhou Y, Zhao Y, Li YE, Masrur A, Yu M. Investigating Linkages Between Spatiotemporal Patterns of the COVID-19 Delta Variant and Public Health Interventions in Southeast Asia: Prospective Space-Time Scan Statistical Analysis Method. JMIR Public Health Surveill 2022; 8:e35840. [PMID: 35861674 PMCID: PMC9364972 DOI: 10.2196/35840] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 05/19/2022] [Accepted: 07/19/2022] [Indexed: 12/18/2022] Open
Abstract
Background The COVID-19 Delta variant has presented an unprecedented challenge to countries in Southeast Asia (SEA). Its transmission has shown spatial heterogeneity in SEA after countries have adopted different public health interventions during the process. Hence, it is crucial for public health authorities to discover potential linkages between epidemic progression and corresponding interventions such that collective and coordinated control measurements can be designed to increase their effectiveness at reducing transmission in SEA. Objective The purpose of this study is to explore potential linkages between the spatiotemporal progression of the COVID-19 Delta variant and nonpharmaceutical intervention (NPI) measures in SEA. We detected the space-time clusters of outbreaks of COVID-19 and analyzed how the NPI measures relate to the propagation of COVID-19. Methods We collected district-level daily new cases of COVID-19 from June 1 to October 31, 2021, and district-level population data in SEA. We adopted prospective space-time scan statistics to identify the space-time clusters. Using cumulative prospective space-time scan statistics, we further identified variations of relative risk (RR) across each district at a half-month interval and their potential public health intervention linkages. Results We found 7 high-risk clusters (clusters 1-7) of COVID-19 transmission in Malaysia, the Philippines, Thailand, Vietnam, and Indonesia between June and August, 2021, with an RR of 5.45 (P<.001), 3.50 (P<.001), 2.30 (P<.001), 1.36 (P<.001), 5.62 (P<.001), 2.38 (P<.001), 3.45 (P<.001), respectively. There were 34 provinces in Indonesia that have successfully mitigated the risk of COVID-19, with a decreasing range between –0.05 and –1.46 due to the assistance of continuous restrictions. However, 58.6% of districts in Malaysia, Singapore, Thailand, and the Philippines saw an increase in the infection risk, which is aligned with their loosened restrictions. Continuous strict interventions were effective in mitigating COVID-19, while relaxing restrictions may exacerbate the propagation risk of this epidemic. Conclusions The analyses of space-time clusters and RRs of districts benefit public health authorities with continuous surveillance of COVID-19 dynamics using real-time data. International coordination with more synchronized interventions amidst all SEA countries may play a key role in mitigating the progression of COVID-19.
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Affiliation(s)
- Wei Luo
- Department of Geography, National University of Singapore, Singapore, Singapore
| | - Zhaoyin Liu
- Department of Geography, National University of Singapore, Singapore, Singapore
| | - Yuxuan Zhou
- Department of Geography, National University of Singapore, Singapore, Singapore
| | - Yumin Zhao
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore, Singapore
| | - Yunyue Elita Li
- Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN, United States
| | - Arif Masrur
- Department of Geography, Pennsylvania State University, State College, PA, United States
| | - Manzhu Yu
- Department of Geography, Pennsylvania State University, State College, PA, United States
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Zhu H, Liu S, Zheng W, Belay H, Zhang W, Qian Y, Wu Y, Delele TG, Jia P. Assessing the dynamic impacts of non-pharmaceutical and pharmaceutical intervention measures on the containment results against COVID-19 in Ethiopia. PLoS One 2022; 17:e0271231. [PMID: 35881650 PMCID: PMC9321453 DOI: 10.1371/journal.pone.0271231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 06/24/2022] [Indexed: 11/18/2022] Open
Abstract
The rapid spread of COVID-19 in Ethiopia was attributed to joint effects of multiple factors such as low adherence to face mask-wearing, failure to comply with social distancing measures, many people attending religious worship activities and holiday events, extensive protests, country election rallies during the pandemic, and the war between the federal government and Tigray Region. This study built a system dynamics model to capture COVID-19 characteristics, major social events, stringencies of containment measures, and vaccination dynamics. This system dynamics model served as a framework for understanding the issues and gaps in the containment measures against COVID-19 in the past period (16 scenarios) and the spread dynamics of the infectious disease over the next year under a combination of different interventions (264 scenarios). In the counterfactual analysis, we found that keeping high mask-wearing adherence since the outbreak of COVID-19 in Ethiopia could have significantly reduced the infection under the condition of low vaccination level or unavailability of the vaccine supply. Reducing or canceling major social events could achieve a better outcome than imposing constraints on people's routine life activities. The trend analysis found that increasing mask-wearing adherence and enforcing more stringent social distancing were two major measures that can significantly reduce possible infections. Higher mask-wearing adherence had more significant impacts than enforcing social distancing measures in our settings. As the vaccination rate increases, reduced efficacy could cause more infections than shortened immunological periods. Offsetting effects of multiple interventions (strengthening one or more interventions while loosening others) could be applied when the levels or stringencies of one or more interventions need to be adjusted for catering to particular needs (e.g., less stringent social distancing measures to reboot the economy or cushion insufficient resources in some areas).
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Affiliation(s)
- Hongli Zhu
- Research Institute of Economics and Management, Southwestern University of Finance and Economics, Chengdu, China
| | - Shiyong Liu
- Institute of Advanced Studies in Humanities and Social Sciences, Beijing Normal University at Zhuhai, Zhuhai, China
| | - Wenwen Zheng
- Personal Finance Department, HQ of China Construction Bank, Beijing, China
| | - Haimanote Belay
- Research Institute of Economics and Management, Southwestern University of Finance and Economics, Chengdu, China
- College of Business and Economics, University of Gondar, Gondar, Ethiopia
| | - Weiwei Zhang
- Research Institute of Economics and Management, Southwestern University of Finance and Economics, Chengdu, China
| | - Ying Qian
- Business School, University of Shanghai for Science & Technology, Shanghai, China
| | - Yirong Wu
- College of Business and Economics, University of Gondar, Gondar, Ethiopia
| | - Tadesse Guadu Delele
- Institute of Advanced Studies in Humanities and Social Sciences, Beijing Normal University at Zhuhai, Zhuhai, China
| | - Peng Jia
- Department of Public Health, College of Medicine & Health Science, University of Gondar, Gondar, Ethiopia
- School of Resources and Environmental Science, Wuhan University, Wuhan, China
- International Institute of Spatial Lifecourse Epidemiology (ISLE), Wuhan, China
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Yuan P, Aruffo E, Tan Y, Yang L, Ogden NH, Fazil A, Zhu H. Projections of the transmission of the Omicron variant for Toronto, Ontario, and Canada using surveillance data following recent changes in testing policies. Infect Dis Model 2022; 7:83-93. [PMID: 35372735 PMCID: PMC8964508 DOI: 10.1016/j.idm.2022.03.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 12/24/2022] Open
Abstract
At the end of 2021, with the rapid escalation of COVID19 cases due to the Omicron variant, testing centers in Canada were overwhelmed. To alleviate the pressure on the PCR testing capacity, many provinces implemented new strategies that promote self testing and adjust the eligibility for PCR tests, making the count of new cases underreported. We designed a novel compartmental model which captures the new testing guidelines, social behaviours, booster vaccines campaign and features of the newest variant Omicron. To better describe the testing eligibility, we considered the population divided into high risk and non-high-risk settings. The model is calibrated using data from January 1 to February 9, 2022, on cases and severe outcomes in Canada, the province of Ontario and City of Toronto. We conduct analyses on the impact of PCR testing capacity, self testing, different levels of reopening and vaccination coverage on cases and severe outcomes. Our results show that the total number of cases in Canada, Ontario and Toronto are 2.34 (95%CI: 1.22-3.38), 2.20 (95%CI: 1.15-3.72), and 1.97(95%CI: 1.13-3.41), times larger than reported cases, respectively. The current testing strategy is efficient if partial restrictions, such as limited capacity in public spaces, are implemented. Allowing more people to have access to PCR reduces the daily cases and severe outcomes; however, if PCR test capacity is insufficient, then it is important to promote self testing. Also, we found that reopening to a pre-pandemic level will lead to a resurgence of the infections, peaking in late March or April 2022. Vaccination and adherence to isolation protocols are important supports to the testing policies to mitigate any possible spread of the virus.
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Affiliation(s)
- Pei Yuan
- Laboratory of Mathematical Parallel Systems (LAMPS), Centre for Diseases Modelling, Department of Mathematics and Statistics, York University, Toronto, ON, Canada
| | - Elena Aruffo
- Laboratory of Mathematical Parallel Systems (LAMPS), Centre for Diseases Modelling, Department of Mathematics and Statistics, York University, Toronto, ON, Canada
| | - Yi Tan
- Laboratory of Mathematical Parallel Systems (LAMPS), Centre for Diseases Modelling, Department of Mathematics and Statistics, York University, Toronto, ON, Canada
| | - Liu Yang
- Laboratory of Mathematical Parallel Systems (LAMPS), Centre for Diseases Modelling, Department of Mathematics and Statistics, York University, Toronto, ON, Canada
| | | | - Aamir Fazil
- Public Health Agency of Canada (PHAC), Ottawa, ON, Canada
| | - Huaiping Zhu
- Laboratory of Mathematical Parallel Systems (LAMPS), Centre for Diseases Modelling, Department of Mathematics and Statistics, York University, Toronto, ON, Canada
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Empirical Modeling of COVID-19 Evolution with High/Direct Impact on Public Health and Risk Assessment. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19063707. [PMID: 35329394 PMCID: PMC8948883 DOI: 10.3390/ijerph19063707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/18/2022] [Accepted: 03/16/2022] [Indexed: 12/28/2022]
Abstract
This report develops a conceivable mathematical model for the transmission and spread of COVID-19 in Romania. Understanding the early spread dynamics of the infection and evaluating the effectiveness of control measures in the first wave of infection is crucial for assessing and evaluating the potential for sustained transmission occurring in the second wave. The main aim of the study was to emphasize the impact of control measures and the rate of case detection in slowing the spread of the disease. Non pharmaceutical control interventions include government actions, public reactions, and other measures. The methodology consists of an empirical model, taking into consideration the generic framework of the Stockholm Environment Institute (SEI) Epidemic–Macroeconomic Model, and incorporates the effect of interventions through a multivalued parameter, a stepwise constant varying during different phases of the interventions designed to capture their impact on the model. The model is mathematically consistent and presents various simulation results using best-estimated parameter values. The model can be easily updated later in response to real-world alterations, for example, the easing of restrictions. We hope that our simulation results may guide local authorities to make timely, correct decisions for public health and risk assessment.
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Rwezaura H, Tchoumi S, Tchuenche J. Impact of environmental transmission and contact rates on Covid-19 dynamics: A simulation study. INFORMATICS IN MEDICINE UNLOCKED 2021; 27:100807. [PMID: 34901380 PMCID: PMC8648373 DOI: 10.1016/j.imu.2021.100807] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/23/2021] [Accepted: 11/23/2021] [Indexed: 01/31/2023] Open
Abstract
The emergence of the COVID-19 pandemic has been a major social and economic challenge globally. Infections from infected surfaces have been identified as drivers of Covid-19 transmission, but many epidemiological models do not include an environmental component to account for indirect transmission. We formulate a deterministic Covid-19 model with both direct and indirect transmissions. The computed basic reproduction number R 0 represents the average number of secondary direct human-to-human infections, and the average number of secondary indirect infections from the environment. Using Partial Rank Correlation Coefficient, we compute sensitivity indices of the basic reproductive number R 0 . As expected, the most significant parameter to reduce initial disease transmission is the natural death rate of pathogens in the environment. Variation of the basic reproduction number for different values of direct and indirect transmissions are numerically investigated. Decreasing the effective direct human-to-human contact rate and indirect transmission from human-to-environment will decrease the spread of the disease as R 0 decreases and vice versa. Since the effective contact rate often accounted for as a factor of the force of infection and other interventions measures such as treatment rate are prominent features of infectious diseases, we consider several functional forms of the incidence function, and numerically investigate their potential impact on the long-term dynamics of the disease. Simulations results revealed some differences for the time and infection to reach its peak. Thus, the choice of the functional form of the force of infection should mainly be influenced by the specifics of the prevention measures being implemented.
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Affiliation(s)
- H. Rwezaura
- Mathematics Department, University of Dar es Salaam, P.O. Box 35062, Dar es Salaam, Tanzania
| | - S.Y. Tchoumi
- Department of Mathematics and Computer Sciences ENSAI, University of Ngaoundere, P.O. Box 455, Ngaoundere, Cameroon,Corresponding author
| | - J.M. Tchuenche
- School of Computational and Communication Sciences and Engineering, Nelson Mandela African Institute of Science and Technology, P.O. Box 447, Arusha, Tanzania
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