An evaluation of the COVID-19 self-service digital contact tracing system in New Zealand

Tim Chambers; Andrew Anglemyer; Andrew Tzer-Yeu Chen; Michael G Baker

doi:10.1016/j.healthpol.2024.105073

An evaluation of the COVID-19 self-service digital contact tracing system in New Zealand

Health Policy. 2024 Apr 17:144:105073. doi: 10.1016/j.healthpol.2024.105073. Online ahead of print.

Authors

Tim Chambers¹, Andrew Anglemyer², Andrew Tzer-Yeu Chen³, Michael G Baker⁴

Affiliations

¹ Department of Public Health, University of Otago, Wellington, New Zealand. Electronic address: tim.chambers@otago.ac.nz.
² Department of Preventive and Social Medicine, University of Otago, Dunedin, New Zealand.
³ Koi Tū: The Centre for Informed Futures, The University of Auckland, New Zealand.
⁴ Department of Public Health, University of Otago, Wellington, New Zealand.

PMID: 38657315
DOI: 10.1016/j.healthpol.2024.105073

Abstract

Background: Digital contact tracing (DCT) aims to improve time-to-isolation (timeliness) and find more potentially exposed individuals (sensitivity) to enhance the utility of contact tracing. The aim of this study was to evaluate the public uptake of a DCT self-service survey and its integration with the Bluetooth exposure notification system within the New Zealand Covid Tracer App (NZCTA).

Methods: We adopted a retrospective cohort study design using community COVID-19 cases from February 2022 to August 2022 in New Zealand (1.2 million cases). We examined the proportion of cases completing a self-service survey and the time to complete the survey by age, sex and ethnicity.

Results: Overall, 66 % of cases completed their self-service survey. Completion was influenced by age, sex and ethnicity. The median completion time was 1.8 h (IQR 0.2, 17.2), with 95 % of those completing this survey doing so within 48 h of case identification. Around 13 % of all survey completers also uploaded their Bluetooth data, which resulted in an average of 663 cases per day notifying 4.5 contacts per case.

Conclusion: The combination of high public uptake and rapid response times suggest self-service DCT could be a useful tool for future outbreaks, particularly if implemented in conjunction with manual processes and other DCT tools (e.g. Bluetooth) to address issues related to performance (sensitivity, timeliness), effectiveness, and health equity.

Keywords: Bluetooth; Contact tracing; Covid-19; Digital contact tracing; Survey.