Understanding Trust and Sustained Use or Abandonment after a Year with the NHS Covid-19 Contact Tracing App in the United Kingdom: A Longitudinal Mixed-Method Study (Preprint)

BACKGROUND Digital contact tracing (DCT) apps have been recently implemented widely as a response to the Covid-19 pandemic. Research has focused on understanding the acceptance and adoption of these apps, but more work is needed to understand which factors may contribute to sustained use of the app. This is key in public health due to DCT apps needing a high uptake rate to decrease transmission of the virus within the general population. OBJECTIVE To understand changes in use of the NHS Test & Trace (T&T) Covid-19 DCT app and to explore how public trust in the app evolved over a one-year period. METHODS A longitudinal mixed-methods approach was conducted consisting of a digital survey in December 2020 followed by another digital survey and interview in November 2021 in which survey responses from 9 participants were explored in detail. Thematic analysis was used to analyse interview transcripts. This paper focuses on the thematic analysis of the qualitative data to unpack the reasoning behind participants answers to the surveys. RESULTS In this paper, five themes generated through thematic analysis are discussed in detail: flaws of the T&T app; usefulness and functionality affecting trust in the app; low trust in UK government; varying degrees of trust in other stakeholders; and public consciousness and compliance dropping over time. Twenty subthemes were developed within these themes. Mistrust evolved from participants’ experiencing sociotechnical flaws of the T&T app and led to concerns over the app’s usefulness. Likewise, mistrust in the government was linked to perceived poor pandemic handling and creation and procurement of the T&T app, including data management. However, more variability in trust in other stakeholders was highlighted, dependent on perceived competence and intentions. For example, Big Tech companies (i.e. Apple, Google), large hospitality venues, and private contractors were seen as more capable, but participants mistrust their intentions, and small hospitality venues, local councils and NHS (i.e. public health system) were seen as well-intentioned but there is mistrust in their ability to handle pandemic matters. Finally, participants reported complying –or not– with T&T and pandemic guidance to different degrees, but overall observed a drop in compliance over time, both at individual and external levels. CONCLUSIONS The findings of this research contribute to the wider implications of sustained app use for public health. Findings suggest that trust in the wider T&T app ecosystem is needed for sustained use of the app. Initial novelty effects occurred with the T&T app, which lessened over time as public concern and media representation of the pandemic decreased and normalisation occurred. Trust in the sociotechnical capabilities of the app, stakeholders involved, and maintaining salience of the T&T app in conjunction with other measures are needed for sustained use.