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Review
. 2023 Dec:5:100103.
doi: 10.1016/j.gloepi.2023.100103. Epub 2023 Mar 9.

Effective contact tracing for COVID-19: A systematic review

Carl-Etienne Juneau  1 , Anne-Sara Briand  2 , Pablo Collazzo  3 , Uwe Siebert  4   5 , Tomas Pueyo  6
Affiliations
Review

Effective contact tracing for COVID-19: A systematic review

Carl-Etienne Juneau et al. Glob Epidemiol. 2023 Dec.

Abstract

Contact tracing is commonly recommended to control outbreaks of COVID-19, but its effectiveness is unclear. Following PRISMA guidelines, we searched four databases using a range of terms related to contact tracing effectiveness for COVID-19. We found 343 papers; 32 were included. All were observational or modelling studies. Observational studies (n = 14) provided consistent, very-low certainty evidence that contact tracing (alone or in combination with other interventions) was associated with better control of COVID-19 (e.g. in Hong Kong, only 1084 cases and four deaths were recorded in the first 4.5 months of the pandemic). Modelling studies (n = 18) provided consistent, high-certainty evidence that under assumptions of prompt and thorough tracing with effective quarantines, contact tracing could stop the spread of COVID-19 (e.g. by reducing the reproduction number from 2.2 to 0.57). A cautious interpretation indicates that to stop the spread of COVID-19, public health practitioners have 2-3 days from the time a new case develops symptoms to isolate the case and quarantine at least 80% of its contacts.

Keywords: COVID-19; Contact tracing; Effectiveness; Epidemic control; Outbreak control; Systematic review.

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Conflict of interest statement

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: CEJ has contractual agreements with the Centre intégré universitaire de santé et de services sociaux du Centre-Sud-de-l'Île-de-Montréal and is founder of the COVID-19 Science Updates.

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