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Automated And Partly Automated Contact Tracing: A Systematic Review To Inform The Control Of COVID-19

Date: January 1 2021


Keywords: ##bibliography #contact #tracing #review #automated #ethics #archive


I. Braithwaite, T. Callender, M. Bullock, and R. W. Aldridge, "Automated and partly automated contact tracing: a systematic review to inform the control of COVID-19," The Lancet Digital Health, vol. 2, no. 11, pp. e607–e621, Nov. 2020, doi: 10.1016/S2589-7500(20)30184-9.

Table of Contents

    1. Implementing Effective Contact Tracing Systems
    2. Barriers and Concerns of Automated Contact Tracing
    3. Key Conclusions of Automated Contact Tracing
  1. How To Cite
  2. References
  3. Discussion:

Implementing Effective Contact Tracing Systems

Effective contact tracing systems rely on detection and isolation of cases which require rapid, active surveillance. [1]

Contact tracers reported an app-based system was faster and more accurate than a paper-based system and reduced travel time. [2] Technical support, like training, was a recurrent theme. Training on the Epi Info Viral Hemorrhagic Fever app in eight countries was often provided by staff who "had received only minimal training themselves" leading to "inefficient and incorrect use". [3] Technical expertise was emphasised as an important but scarce resource in two other studies. [2], [4] Training contact tracers took between 2-3 days [4], [5]

Barriers and Concerns of Automated Contact Tracing

The aspects involved in implementing automated contact tracing, such as the practical, technical, legal, and ethical, are complicated. [6]–[8] Uptake, privacy, security, and testing access have been identified as potential barriers to effectiveness. [7], [9] Automated contact tracing could lead to unprecedented surveillance and eroded public trust, if data is misused. [10]

With assumed 75% uptake of the system, Suppressing the COVID19 outbreak required concurrent measures (e.g., shielding vulnerable groups, [11] remote working, and limiting the number of contacts per day to fewer than 10 outside of work and school) [12] alongside automated contact tracing. According to Hinch and colleagues [11] most cases did not result in containment, except when quarantining all household members of contacts who had direct contact with a case (recursive contact tracing). [13]

Key Conclusions of Automated Contact Tracing

Key questions before implementing an automated contact-tracing system to be asked:

  1. Have public acceptability and privacy concerns been addressed

  2. How the system is implemented with public health expert supervision

  3. Likelihood of effectivity, cost, and equity of solution. [14], [15]

Manual contact tracing could be improved by or work with automated approaches. It could contribute to reducing transmission and offsetting work of manual contact tracing. Benefits of automated approaches should be weighed against implementation costs and broader risks.

The effectiveness of automated contact tracing in reducing disease transmission depends on both population uptake and timeliness of intervention. [16] As with manual contact tracing, automated contact tracing relies on accurate and reliable identification of encounters during which transmission occurs. Technology could be used for automated processing of test results or symptom reports and by use of smartphone sensors to identify and notify contacts instantaneously who are at risk of infection. [16]–[18]

How To Cite

Zelko, Jacob. Automated And Partly Automated Contact Tracing: A Systematic Review To Inform The Control Of COVID-19. January 1 2021.


[1] World Health Organization, “COVID-19 Strategy Update,” World Health Organization, Apr. 2020. Accessed: Nov. 09, 2020. [Online]. Available:

[2] L. O. Danquah et al., “Use of a mobile application for Ebola contact tracing and monitoring in northern Sierra Leone: A proof-of-concept study,” BMC Infect. Dis., vol. 19, no. 1, p. 810, 2019.

[3] I. J. Schafer, E. Knudsen, L. A. McNamara, S. Agnihotri, P. E. Rollin, and A. Islam, “The Epi Info Viral Hemorrhagic Fever (VHF) application: A resource for outbreak data management and contact tracing in the 2014–2016 West Africa Ebola epidemic,” J. Infect. Dis., vol. 214, pp. S122–S136, 2016.

[4] D. Tom-Aba et al., “Innovative technological approach to Ebola virus disease outbreak response in Nigeria using the open data kit and form hub technology,” PloS one, vol. 10, no. 6, p. e0131000, 2015.

[5] J. A. Sacks et al., “Introduction of mobile health tools to support Ebola surveillance and contact tracing in Guinea,” Glob. Health Sci. Pract., vol. 3, no. 4, pp. 646–659, 2015.

[6] M. Burgess, “Why the NHS Covid-19 contact tracing app failed,” Wired UK, Jun. 19, 2020. Accessed: Nov. 09, 2020. [Online]. Available:

[7] Ada Lovelace Institute, “Ada Lovelace Institute Rapid Evidence Review: Exit through the App Store?” Ada Lovelace Institute, Apr. 2020. Accessed: Nov. 09, 2020. [Online]. Available:

[8] M. Klenk, H. Duijf, and C. Engels, “Ethics of digital contact tracing and COVID-19: Who is (not) free to go?” Available SSRN 3595394, 2020.

[9] H. Cho, D. Ippolito, and Y. W. Yu, “Contact tracing mobile apps for COVID-19: Privacy considerations and related trade-offs,” 2020.Available:

[10] S. Venkataramakrishnan, “Contact-tracing apps must not be used for mass surveillance, warn experts,” Apr. 20, 2020. (accessed Nov. 09, 2020).

[11] R. Hinch et al., “Effective configurations of a digital contact tracing app: A report to NHSX,” En InApr 2020 Available Here Url Httpsgithub ComBDI-Pathog.-19instanttracingblobmasterReport, 2020.

[12] A. J. Kucharski et al., “Effectiveness of isolation, testing, contact tracing and physical distancing on reducing transmission of SARS-CoV-2 in different settings,” medRxiv, 2020.

[13] D. Moher, A. Liberati, J. Tetzlaff, D. G. Altman, P. Group, et al., “Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement,” PLoS med, vol. 6, no. 7, p. e1000097, 2009.

[14] C. Fraser, L. Abeler-Dörner, L. Ferretti, M. Parker, M. Kendall, and D. Bonsall, “Digital contact tracing: Comparing the capabilities of centralised and decentralised data architectures to effectively suppress the COVID-19 epidemic whilst maximising freedom of movement and maintaining privacy,” Univ. Oxf., 2020.

[15] J. Hellewell et al., “Feasibility of controlling COVID-19 outbreaks by isolation of cases and contacts,” Lancet Glob. Health, 2020.

[16] L. Ferretti et al., “Quantifying SARS-CoV-2 transmission suggests epidemic control with digital contact tracing,” Science, vol. 368, no. 6491, 2020.

[17] M. N. Lochlainn et al., “Key predictors of attending hospital with COVID19: An association study from the COVID Symptom Tracker App in 2,618,948 individuals,” medRxiv, 2020.

[18] J. Chan et al., “Pact: Privacy sensitive protocols and mechanisms for mobile contact tracing,” 2020.Available:


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