1
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Zhang D, Britton T. An SEIR network epidemic model with manual and digital contact tracing allowing delays. Math Biosci 2024; 374:109231. [PMID: 38914260 DOI: 10.1016/j.mbs.2024.109231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 06/03/2024] [Accepted: 06/04/2024] [Indexed: 06/26/2024]
Abstract
We consider an SEIR epidemic model on a network also allowing random contacts, where recovered individuals could either recover naturally or be diagnosed. Upon diagnosis, manual contact tracing is triggered such that each infected network contact is reported, tested and isolated with some probability and after a random delay. Additionally, digital tracing (based on a tracing app) is triggered if the diagnosed individual is an app-user, and then all of its app-using infectees are immediately notified and isolated. The early phase of the epidemic with manual and/or digital tracing is approximated by different multi-type branching processes, and three respective reproduction numbers are derived. The effectiveness of both contact tracing mechanisms is numerically quantified through the reduction of the reproduction number. This shows that app-using fraction plays an essential role in the overall effectiveness of contact tracing. The relative effectiveness of manual tracing compared to digital tracing increases if: more of the transmission occurs on the network, when the tracing delay is shortened, and when the network degree distribution is heavy-tailed. For realistic values, the combined tracing case can reduce R0 by 20%-30%, so other preventive measures are needed to reduce the reproduction number down to 1.2-1.4 for contact tracing to make it successful in avoiding big outbreaks.
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Affiliation(s)
- Dongni Zhang
- Department of Mathematics, Stockholm University, 106 91 Stockholm, Sweden.
| | - Tom Britton
- Department of Mathematics, Stockholm University, 106 91 Stockholm, Sweden
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2
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Chambers T, Anglemyer A, Chen A, Atkinson J, Baker MG. Population and contact tracer uptake of New Zealand's QR-code-based digital contact tracing app for COVID-19. Epidemiol Infect 2024; 152:e66. [PMID: 38629265 PMCID: PMC11062780 DOI: 10.1017/s0950268824000608] [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: 10/04/2023] [Revised: 02/27/2024] [Accepted: 04/10/2024] [Indexed: 04/30/2024] Open
Abstract
This study aimed to understand the population and contact tracer uptake of the quick response (QR)-code-based function of the New Zealand COVID Tracer App (NZCTA) used for digital contact tracing (DCT). We used a retrospective cohort of all COVID-19 cases between August 2020 and February 2022. Cases of Asian and other ethnicities were 2.6 times (adjusted relative risk (aRR) 2.58, 99 per cent confidence interval (95% CI) 2.18, 3.05) and 1.8 times (aRR 1.81, 95% CI 1.58, 2.06) more likely than Māori cases to generate a token during the Delta period, and this persisted during the Omicron period. Contact tracing organization also influenced location token generation with cases handled by National Case Investigation Service (NCIS) staff being 2.03 (95% CI 1.79, 2.30) times more likely to generate a token than cases managed by clinical staff at local Public Health Units (PHUs). Public uptake and participation in the location-based system independent of contact tracer uptake were estimated at 45%. The positive predictive value (PPV) of the QR code system was estimated to be close to nil for detecting close contacts but close to 100% for detecting casual contacts. Our paper shows that the QR-code-based function of the NZCTA likely made a negligible impact on the COVID-19 response in New Zealand (NZ) in relation to isolating potential close contacts of cases but likely was effective at identifying and notifying casual contacts.
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Affiliation(s)
- Tim Chambers
- Department of Public Health, University of Otago, Wellington, New Zealand
| | - Andrew Anglemyer
- Department of Preventive and Social Medicine, University of Otago, Dunedin, New Zealand
| | - Andrew Chen
- Koi Tū: The Centre for Informed Futures, The University of Auckland, Auckland, New Zealand
| | - June Atkinson
- Department of Public Health, University of Otago, Wellington, New Zealand
| | - Michael G. Baker
- Department of Public Health, University of Otago, Wellington, New Zealand
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Ter Haar W, Bosdriesz J, Venekamp RP, Schuit E, van den Hof S, Ebbers W, Kretzschmar M, Kluijtmans J, Moons C, Schim van der Loeff M, Matser A, van de Wijgert JHHM. The epidemiological impact of digital and manual contact tracing on the SARS-CoV-2 epidemic in the Netherlands: Empirical evidence. PLOS DIGITAL HEALTH 2023; 2:e0000396. [PMID: 38157381 PMCID: PMC10756539 DOI: 10.1371/journal.pdig.0000396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 10/23/2023] [Indexed: 01/03/2024]
Abstract
The Dutch government introduced the CoronaMelder smartphone application for digital contact tracing (DCT) to complement manual contact tracing (MCT) by Public Health Services (PHS) during the 2020-2022 SARS-CoV-2 epidemic. Modelling studies showed great potential but empirical evidence of DCT and MCT impact is scarce. We determined reasons for testing, and mean exposure-testing intervals by reason for testing, using routine data from PHS Amsterdam (1 December 2020 to 31 May 2021) and data from two SARS-CoV-2 rapid diagnostic test accuracy studies at other PHS sites in the Netherlands (14 December 2020 to 18 June 2021). Throughout the study periods, notification of DCT-identified contacts was via PHS contact-tracers, and self-testing was not yet widely available. The most commonly reported reason for testing was having symptoms. In asymptomatic individuals, it was having been warned by an index case. Only around 2% and 2-5% of all tests took place after DCT or MCT notification, respectively. About 20-36% of those who had received a DCT or MCT notification had symptoms at the time of test request. Test positivity after a DCT notification was significantly lower, and exposure-test intervals after a DCT or MCT notification were longer, than for the above-mentioned other reasons for testing. Our data suggest that the impact of DCT and MCT on the SARS-CoV-2 epidemic in the Netherlands was limited. However, DCT impact might be enlarged if app use coverage is improved, contact-tracers are eliminated from the digital notification process to minimise delays, and DCT is combined with self-testing.
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Affiliation(s)
- Wianne Ter Haar
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
- Public Health Service (GGD) of Amsterdam, Amsterdam, Netherlands
| | - Jizzo Bosdriesz
- Public Health Service (GGD) of Amsterdam, Amsterdam, Netherlands
- Department of Internal Medicine, Division of Infectious Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Roderick P. Venekamp
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Ewoud Schuit
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Susan van den Hof
- National Institute for Public Health and the Environment, Bilthoven, Netherlands
| | - Wolfgang Ebbers
- Department of Public Administration and Sociology, Erasmus University Rotterdam, Rotterdam, Netherlands
| | - Mirjam Kretzschmar
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
- National Institute for Public Health and the Environment, Bilthoven, Netherlands
| | - Jan Kluijtmans
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Carl Moons
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Maarten Schim van der Loeff
- Public Health Service (GGD) of Amsterdam, Amsterdam, Netherlands
- Department of Internal Medicine, Division of Infectious Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Amy Matser
- Public Health Service (GGD) of Amsterdam, Amsterdam, Netherlands
- Department of Internal Medicine, Division of Infectious Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Janneke H. H. M. van de Wijgert
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
- National Institute for Public Health and the Environment, Bilthoven, Netherlands
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Muwonge A, Wee BA, Mugerwa I, Nabunya E, Mpyangu CM, Bronsvoort BMDC, Ssebaggala ER, Kiayias A, Mwaka E, Joloba M. An open-source digital contact tracing system tailored to haulage. Front Digit Health 2023; 5:1199635. [PMID: 37538199 PMCID: PMC10394895 DOI: 10.3389/fdgth.2023.1199635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 07/06/2023] [Indexed: 08/05/2023] Open
Abstract
Digital contact tracing presents numerous advantages compared to manual contact tracing methods, especially in terms of enhanced speed and automation. Nevertheless, a lack of comprehensive evaluation regarding functionality, efficiency, benefits, and acceptance within communities remains. Here we primarily focus on the functionality of THEA-GS, an open-source digital contact tracing tool developed through consultation with stakeholders. Additionally, we provide insights from its implementation on a limited sample of haulage drivers in Uganda, serving as a representative case for a low- and middle-income country. THEA-GS comprises two primary components: (a) a smartphone application, and (b) a suite of server-programs responsible for data processing and analysis, including databases and a web-based interface featuring dashboards. In essence, the mobile application records the timestamped location of haulage drivers within the road network and identifies possible transmission hotspots by analyzing factors such as the duration of stops and the communities associated with them. The tool can be integrated with national infrastructure to compare drivers' diagnostic results and contact structure, thereby generating individual and community risk assessments relative to the road network. During the Omicron-variant wave of the COVID-19 pandemic, a total of 3,270 haulage drivers were enrolled between October 2021 and October 2022. Around 75% of these drivers utilized THEA-GS for approximately two months. Based on an analysis of 3,800 test results, which included 48 positive cases, 125 contacts, and 40 million time-stamped GPS points, THEA-GS shows a significant speed improvement, being approximately 90 times faster than MCT. For instance, the average time from sample collection to notifying a case and their contacts was approximately 70 and 80 min, respectively. The adoption of this tool encountered challenges, mainly due to drivers' awareness of its purpose and benefits for public health. THEA-GS is a place-based digital contact tracing tool specifically designed to assist National Public Health Institutions in managing infectious disease outbreaks involving the haulage industry as a high-risk group. While its utility, acceptance, and accuracy have not been fully evaluated, our preliminary tests conducted in Uganda indicate the tool's functionality is robust, but social acceptance and adoption are heavily reliant on establishing trust among users.
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Affiliation(s)
- Adrian Muwonge
- Digital One Health Laboratory, The Roslin Institute, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom
- Blockchain Technology Laboratory, School of Informatics, University of Edinburgh, Edinburgh, United Kingdom
| | - Bryan A. Wee
- Digital One Health Laboratory, The Roslin Institute, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Emma Nabunya
- School of Biomedical Sciences, College of Health Sciences, Makerere University, Kampala, Uganda
| | | | - Barend M. de C. Bronsvoort
- Digital One Health Laboratory, The Roslin Institute, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Aggelos Kiayias
- Blockchain Technology Laboratory, School of Informatics, University of Edinburgh, Edinburgh, United Kingdom
| | - Erisa Mwaka
- Department of Anatomy, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Moses Joloba
- School of Biomedical Sciences, College of Health Sciences, Makerere University, Kampala, Uganda
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Chen S(J, Tran KT, Xia Z(R, Waseem D, Zhang JA, Potdar B. The double-edged effects of data privacy practices on customer responses. INTERNATIONAL JOURNAL OF INFORMATION MANAGEMENT 2023. [DOI: 10.1016/j.ijinfomgt.2022.102600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Handmann E, Camanor SW, Fallah MP, Candy N, Parker D, Gries A, Grünewald T. Feasibility of digital contact tracing in low-income settings - pilot trial for a location-based DCT app. BMC Public Health 2023; 23:146. [PMID: 36670358 PMCID: PMC9859743 DOI: 10.1186/s12889-022-14888-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Accepted: 12/16/2022] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Data about the effectiveness of digital contact tracing are based on studies conducted in countries with predominantly high- or middle-income settings. Up to now, little research is done to identify specific problems for the implementation of such technique in low-income countries. METHODS A Bluetooth-assisted GPS location-based digital contact tracing (DCT) app was tested by 141 participants during 14 days in a hospital in Monrovia, Liberia in February 2020. The DCT app was compared to a paper-based reference system. Hits between participants and 10 designated infected participants were recorded simultaneously by both methods. Additional data about GPS and Bluetooth adherence were gathered and surveys to estimate battery consumption and app adherence were conducted. DCT apps accuracy was evaluated in different settings. RESULTS GPS coordinates from 101/141 (71.6%) participants were received. The number of hours recorded by the participants during the study period, true Hours Recorded (tHR), was 496.3 h (1.1% of maximum Hours recordable) during the study period. With the paper-based method 1075 hits and with the DCT app five hits of designated infected participants with other participants have been listed. Differences between true and maximum recording times were due to failed permission settings (45%), data transmission issues (11.3%), of the participants 10.1% switched off GPS and 32.5% experienced other technical or compliance problems. In buildings, use of Bluetooth increased the accuracy of the DCT app (GPS + BT 22.9 m ± 21.6 SD vs. GPS 60.9 m ± 34.7 SD; p = 0.004). GPS accuracy in public transportation was 10.3 m ± 10.05 SD with a significant (p = 0.007) correlation between precision and phone brand. GPS resolution outdoors was 10.4 m ± 4.2 SD. CONCLUSION In our study several limitations of the DCT together with the impairment of GPS accuracy in urban settings impede the solely use of a DCT app. It could be feasible as a supplement to traditional manual contact tracing. DKRS, DRKS00029327 . Registered 20 June 2020 - Retrospectively registered.
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Affiliation(s)
- Eric Handmann
- Department for Emergency Medicine, University Hospital Leipzig, Leipzig, Germany.
| | | | - Mosoka P. Fallah
- grid.512250.1National Public Health Institute of Liberia (NPHIL), Monrovia, Liberia
| | - Neima Candy
- grid.512250.1National Public Health Institute of Liberia (NPHIL), Monrovia, Liberia
| | | | - André Gries
- grid.411339.d0000 0000 8517 9062Department for Emergency Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Thomas Grünewald
- grid.459629.50000 0004 0389 4214Clinic for Infectious Diseases and Tropical Medicine and Department for Hospital and Environmental Hygiene, Klinikum Chemnitz, Chemnitz, Germany
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7
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Understanding the impact of digital contact tracing during the COVID-19 pandemic. PLOS DIGITAL HEALTH 2022; 1:e0000149. [PMID: 36812611 PMCID: PMC9931320 DOI: 10.1371/journal.pdig.0000149] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 10/23/2022] [Indexed: 12/12/2022]
Abstract
Digital contact tracing (DCT) applications have been introduced in many countries to aid the containment of COVID-19 outbreaks. Initially, enthusiasm was high regarding their implementation as a non-pharmaceutical intervention (NPI). However, no country was able to prevent larger outbreaks without falling back to harsher NPIs. Here, we discuss results of a stochastic infectious-disease model that provide insights in how the progression of an outbreak and key parameters such as detection probability, app participation and its distribution, as well as engagement of users impact DCT efficacy informed by results of empirical studies. We further show how contact heterogeneity and local contact clustering impact the intervention's efficacy. We conclude that DCT apps might have prevented cases on the order of single-digit percentages during single outbreaks for empirically plausible ranges of parameters, ignoring that a substantial part of these contacts would have been identified by manual contact tracing. This result is generally robust against changes in network topology with exceptions for homogeneous-degree, locally-clustered contact networks, on which the intervention prevents more infections. An improvement of efficacy is similarly observed when app participation is highly clustered. We find that DCT typically averts more cases during the super-critical phase of an epidemic when case counts are rising and the measured efficacy therefore depends on the time of evaluation.
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Buesching FB, Steininger DM, Veit DJ. Governing digital crisis responses: platform standards and the dilemma of COVID-19 contact tracing. JOURNAL OF BUSINESS ECONOMICS 2022; 93:267-323. [PMID: 38013850 PMCID: PMC9672648 DOI: 10.1007/s11573-022-01118-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Accepted: 10/12/2022] [Indexed: 11/19/2022]
Abstract
In response to the impact of the SARS-CoV-2 (COVID-19) pandemic, various developers turned to smartphone-based contact tracing to address the challenges of manual tracing. Due to the presence of network effects, i.e., the effectiveness of contact tracing applications increases with the number of users, information technology standards were critical to the technology's success. The standardization efforts in Europe led to a variety of trade-offs concerning the choice of an appropriate technological architecture due to the contradictory tensions resulting from the dualism between the need for contact tracing data to contain the pandemic and the need for data minimization to preserve user privacy. Drawing predominantly on the software platform and standards literature, we conduct an interpretive case study to examine the emergence and consequences of this multi-layered decision situation. Our findings reveal how Google and Apple were able to limit the individual leeway of external developers, thereby effectively resolving the European standards war. Furthermore, we identify and discuss the various short-term and long-term trade-offs associated with the standardization of contact tracing applications and translate our findings into recommendations for policy makers with respect to future crisis situations. Specifically, we propose a strategy grounded in our data that enables responsible actors to make goal-oriented and rapid decisions under time constraints.
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Affiliation(s)
- Felix B. Buesching
- University of Augsburg, Universitaetsstrasse 16, 86159 Augsburg, Germany
| | - Dennis M. Steininger
- University of Kaiserslautern, Kurt-Schumacher-Strasse 74a, 67663 Kaiserslautern, Germany
| | - Daniel J. Veit
- University of Augsburg, Universitaetsstrasse 16, 86159 Augsburg, Germany
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Wu M, Li C, Shen Z, He S, Tang L, Zheng J, Fang Y, Li K, Cheng Y, Shi Z, Sheng G, Liu Y, Zhu J, Ye X, Chen J, Chen W, Li L, Sun Y, Chen J. Use of temporal contact graphs to understand the evolution of COVID-19 through contact tracing data. COMMUNICATIONS PHYSICS 2022; 5:270. [PMID: 36373056 PMCID: PMC9638278 DOI: 10.1038/s42005-022-01045-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 10/17/2022] [Indexed: 06/16/2023]
Abstract
Digital contact tracing has been recently advocated by China and many countries as part of digital prevention measures on COVID-19. Controversies have been raised about their effectiveness in practice as it remains open how they can be fully utilized to control COVID-19. In this article, we show that an abundance of information can be extracted from digital contact tracing for COVID-19 prevention and control. Specifically, we construct a temporal contact graph that quantifies the daily contacts between infectious and susceptible individuals by exploiting a large volume of location-related data contributed by 10,527,737 smartphone users in Wuhan, China. The temporal contact graph reveals five time-varying indicators can accurately capture actual contact trends at population level, demonstrating that travel restrictions (e.g., city lockdown) in Wuhan played an important role in containing COVID-19. We reveal a strong correlation between the contacts level and the epidemic size, and estimate several significant epidemiological parameters (e.g., serial interval). We also show that user participation rate exerts higher influence on situation evaluation than user upload rate does, indicating a sub-sampled dataset would be as good at prediction. At individual level, however, the temporal contact graph plays a limited role, since the behavior distinction between the infected and uninfected individuals are not substantial. The revealed results can tell the effectiveness of digital contact tracing against COVID-19, providing guidelines for governments to implement interventions using information technology.
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Affiliation(s)
- Mincheng Wu
- State Key Laboratory of Industrial Control Technology, Zhejiang University, Hangzhou, 310027 China
- College of Control Science and Engineering, Zhejiang University, Hangzhou, 310027 China
| | - Chao Li
- State Key Laboratory of Industrial Control Technology, Zhejiang University, Hangzhou, 310027 China
- College of Control Science and Engineering, Zhejiang University, Hangzhou, 310027 China
| | - Zhangchong Shen
- College of Control Science and Engineering, Zhejiang University, Hangzhou, 310027 China
| | - Shibo He
- State Key Laboratory of Industrial Control Technology, Zhejiang University, Hangzhou, 310027 China
- College of Control Science and Engineering, Zhejiang University, Hangzhou, 310027 China
| | - Lingling Tang
- Shulan (Hangzhou) Hospital Affiliated to Shulan International Medical College, Zhejiang Shuren University, Hangzhou, 310015 China
| | - Jie Zheng
- Zhejiang Institute of Medical-care Information Technology, Hangzhou, 311100 China
| | - Yi Fang
- Westlake Institute for Data Intelligence, Hangzhou, 310012 China
| | - Kehan Li
- College of Control Science and Engineering, Zhejiang University, Hangzhou, 310027 China
| | - Yanggang Cheng
- College of Control Science and Engineering, Zhejiang University, Hangzhou, 310027 China
| | - Zhiguo Shi
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027 China
| | - Guoping Sheng
- Shulan (Hangzhou) Hospital Affiliated to Shulan International Medical College, Zhejiang Shuren University, Hangzhou, 310015 China
| | - Yu Liu
- Westlake Institute for Data Intelligence, Hangzhou, 310012 China
| | - Jinxing Zhu
- Westlake Institute for Data Intelligence, Hangzhou, 310012 China
| | - Xinjiang Ye
- Westlake Institute for Data Intelligence, Hangzhou, 310012 China
| | - Jinlai Chen
- Westlake Institute for Data Intelligence, Hangzhou, 310012 China
| | - Wenrong Chen
- Westlake Institute for Data Intelligence, Hangzhou, 310012 China
| | - Lanjuan Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, 310027 China
| | - Youxian Sun
- State Key Laboratory of Industrial Control Technology, Zhejiang University, Hangzhou, 310027 China
- College of Control Science and Engineering, Zhejiang University, Hangzhou, 310027 China
| | - Jiming Chen
- State Key Laboratory of Industrial Control Technology, Zhejiang University, Hangzhou, 310027 China
- College of Control Science and Engineering, Zhejiang University, Hangzhou, 310027 China
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Ellmann S, Maryschok M, Schöffski O, Emmert M. The German COVID-19 Digital Contact Tracing App: A Socioeconomic Evaluation. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:14318. [PMID: 36361198 PMCID: PMC9654962 DOI: 10.3390/ijerph192114318] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/29/2022] [Accepted: 10/31/2022] [Indexed: 06/16/2023]
Abstract
The COVID-19 pandemic posed challenges to governments in terms of contact tracing. Like many other countries, Germany introduced a mobile-phone-based digital contact tracing solution ("Corona Warn App"; CWA) in June 2020. At the time of its release, however, it was hard to assess how effective such a solution would be, and a political and societal debate arose regarding its efficiency, also in light of its high costs. This study aimed to analyze the effectiveness of the CWA, considering prevented infections, hospitalizations, intensive care treatments, and deaths. In addition, its efficiency was to be assessed from a monetary point of view, and factors with a significant influence on the effectiveness and efficiency of the CWA were to be determined. Mathematical and statistical modeling was used to calculate infection cases prevented by the CWA, along with the numbers of prevented complications (hospitalizations, intensive care treatments, deaths) using publicly available CWA download numbers and incidences over time. The monetized benefits of these prevented cases were quantified and offset against the costs incurred. Sensitivity analysis was used to identify factors critically influencing these parameters. Between June 2020 and April 2022, the CWA prevented 1.41 million infections, 17,200 hospitalizations, 4600 intensive care treatments, and 7200 deaths. After offsetting costs and benefits, the CWA had a net present value of EUR 765 m in April 2022. Both the effectiveness and efficiency of the CWA are decisively and disproportionately positively influenced by the highest possible adoption rate among the population and a high rate of positive infection test results shared via the CWA.
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Affiliation(s)
- Stephan Ellmann
- Department of Radiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, University Hospital Erlangen, Maximiliansplatz 3, 91054 Erlangen, Germany
| | - Markus Maryschok
- School of Business, Economics and Society, Chair for Health Management, Friedrich-Alexander-Universität Erlangen-Nürnberg, Lange Gasse 20, 90403 Nürnberg, Germany
| | - Oliver Schöffski
- School of Business, Economics and Society, Chair for Health Management, Friedrich-Alexander-Universität Erlangen-Nürnberg, Lange Gasse 20, 90403 Nürnberg, Germany
| | - Martin Emmert
- Faculty of Law, Business and Economics, Institute for Healthcare Management and Health Sciences, University of Bayreuth, Prieserstraße 2, 95444 Bayreuth, Germany
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Liu J, Ong GP, Pang VJ. Modelling effectiveness of COVID-19 pandemic control policies using an Area-based SEIR model with consideration of infection during interzonal travel. TRANSPORTATION RESEARCH. PART A, POLICY AND PRACTICE 2022; 161:25-47. [PMID: 35603124 PMCID: PMC9110328 DOI: 10.1016/j.tra.2022.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
This paper studies the effectiveness of several pandemic restriction measures adopted in Singapore during the COVID-19 outbreak. To this end, the classical Susceptible-Exposed-Infectious-Recovered (SEIR) model widely used to describe the dynamic process of epidemic propagation is extended to an area-based SEIR model with the consideration of exposure to infections during commute and quarantine. The proposed model considers infections within areas and infections occurred during the commute of individuals. A case study of the Singapore MRT system is presented to show the effectiveness of pandemic restriction policies implemented in Singapore, namely social distancing, work shift and Circuit Breaker (CB) and phase advisories. A long-term investigation of COVID-19 pandemic in Singapore is performed, and the disease transmission dynamics in 2020-2021 (which covers the first wave and second wave of COVID-19 pandemic in Singapore) is modelled.
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Affiliation(s)
- Jielun Liu
- Department of Civil & Environmental Engineering, National University of Singapore, 117576, Singapore
| | - Ghim Ping Ong
- Department of Civil & Environmental Engineering, National University of Singapore, 117576, Singapore
| | - Vincent Junxiong Pang
- Saw Swee Hock School of Public Health, National University of Singapore, 117549, Singapore
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12
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Ballouz T, Menges D, Aschmann HE, Jung R, Domenghino A, Fehr JS, Puhan MA, von Wyl V. Individual-level Evaluation of the Exposure Notification Cascade in the SwissCovid Digital Proximity Tracing App: An Observational Study. JMIR Public Health Surveill 2022; 8:e35653. [PMID: 35476726 PMCID: PMC9122110 DOI: 10.2196/35653] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 02/03/2022] [Accepted: 04/26/2022] [Indexed: 12/31/2022] Open
Abstract
Background Digital proximity tracing (DPT) aims to complement manual contact tracing (MCT) in identifying exposed contacts and preventing further transmission of SARS-CoV-2 in the population. Although several DPT apps, including SwissCovid, have shown to have promising effects on mitigating the pandemic, several challenges have impeded them from fully achieving the desired results. A key question now relates to how the effectiveness of DPT can be improved, which requires a better understanding of factors influencing its processes. Objective In this study, we aim to provide a detailed examination of the exposure notification (EN) cascade and to evaluate potential contextual influences for successful receipt of an EN and subsequent actions taken by cases and contacts in different exposure settings. Methods We used data from 285 pairs of SARS-CoV-2-infected cases and their contacts within an observational cohort study of cases and contacts identified by MCT and enrolled between August 6, 2020, and January 17, 2021, in the canton of Zurich, Switzerland. We surveyed participants with electronic questionnaires. Data were summarized descriptively and stratified by exposure setting. Results We found that only 79 (58.5%) of 135 contacts using the SwissCovid app whose corresponding cases reported to have triggered the EN also received one. Of these, 18 (22.8%) received the EN before MCT. Compared to those receiving an EN after MCT (61/79, 77.2%), we observed that a higher proportion of contacts receiving an EN before MCT were exposed in nonhousehold settings (11/18, 61.1%, vs 34/61, 55.7%) and their corresponding cases had more frequently reported mild-to-moderate symptoms (14/18, 77.8%, vs 42/61, 68.9%). Of the 18 contacts receiving an EN before MCT, 14 (77.8%) took recommended measures: 12 (66.7%) were tested for SARS-CoV-2, and 7 (38.9%) called the SwissCovid Infoline. In nonhousehold settings, the proportion of contacts taking preventive actions after receiving an EN was higher compared to same-household settings (82%, vs 67%). In addition, 1 (9%) of 11 ENs received in the nonhousehold setting before MCT led to the identification of a SARS-CoV-2-infected case by prompting the contact to get tested. This corresponds to 1 in 85 exposures of a contact to a case in a nonhousehold setting, in which both were app users and the case triggered the EN. Conclusions Our descriptive evaluation of the DPT notification cascade provides further evidence that DPT is an important complementary tool in pandemic mitigation, especially in nonhousehold exposure settings. However, the effect of DPT apps can only be exerted if code generation processes are efficient and exposed contacts are willing to undertake preventive actions. This highlights the need to focus efforts on keeping barriers to efficient code generation as low as possible and promoting not only app adoption but also compliance with the recommended measures upon an EN. Trial Registration International Standard Randomised Controlled Trial Number Registry 14990068; https://doi.org/10.1186/ISRCTN14990068
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Affiliation(s)
- Tala Ballouz
- Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Hirschengraben 84, Zurich, CH
| | - Dominik Menges
- Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Hirschengraben 84, Zurich, CH
| | - Hélène E Aschmann
- Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Hirschengraben 84, Zurich, CH.,Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, US
| | - Ruedi Jung
- Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Hirschengraben 84, Zurich, CH
| | - Anja Domenghino
- Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Hirschengraben 84, Zurich, CH.,Department of Visceral and Transplantation Surgery, University Hospital Zurich (USZ), University of Zurich, Zurich, CH
| | - Jan S Fehr
- Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Hirschengraben 84, Zurich, CH
| | - Milo Alan Puhan
- Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Hirschengraben 84, Zurich, CH
| | - Viktor von Wyl
- Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Hirschengraben 84, Zurich, CH.,Institute for Implementation Science in Health Care, University of Zurich, Zurich, CH
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Niwa M, Lim Y, Sengoku S, Kodama K. A Layered Adopter-Structure Model for the Download of COVID-19 Contact Tracing Apps: A System Dynamics Study for mHealth Penetration. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:4331. [PMID: 35410014 PMCID: PMC8998972 DOI: 10.3390/ijerph19074331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 03/31/2022] [Accepted: 04/01/2022] [Indexed: 02/05/2023]
Abstract
(1) Background: Contact tracing and notification apps for coronavirus disease 2019 (COVID-19) are installed on smartphones and are intended to detect contact with another person's device. A high installation rate is important for these apps to enable them to be effective countermeasures against the silent transmission of diseases. However, the installation rate varies among apps and regions and the penetration dynamics of these applications are unclear. (2) Methods: The download behavior of contact tracing applications was investigated using publicly available datasets. The increase in downloads was modeled using a system dynamics model derived from the product growth model. (3) Results: The imitation effects present in the traditional product growth model were not observed in COVID-19 contact tracing apps. The system dynamics model, without the imitation effect, identified the downloads of the Australian COVIDSafe app. The system dynamics model, with a layered adopter, identified the downloads of the Japanese tracing app COCOA. The spread of COVID-19 and overall anti-COVID-19 government intervention measures in response to the spread of infection seemed to result in an increase in downloads. (4) Discussion: The suggested layered structure of users implied that individualized promotion for each layer was important. Addressing the issues among users who are skeptical about adoption is pertinent for optimal penetration of the apps.
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Affiliation(s)
- Makoto Niwa
- Graduate School of Technology Management, Ritsumeikan University, Ibaraki 567-8570, Japan;
- Discovery Research Laboratories, Nippon Shinyaku Co., Ltd., Kyoto 601-8550, Japan
| | - Yeongjoo Lim
- Faculty of Business Administration, Ritsumeikan University, Ibaraki 567-8570, Japan;
| | - Shintaro Sengoku
- Life Style by Design Research Unit, Institute for Future Initiatives, University of Tokyo, Tokyo 113-0033, Japan;
| | - Kota Kodama
- Graduate School of Technology Management, Ritsumeikan University, Ibaraki 567-8570, Japan;
- Center for Research and Education on Drug Discovery, The Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
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