COVID-19 digital contact tracing: a cross-sectional survey on drivers of nonuse, use discontinuation and acceptance of app options. (Preprint)

BACKGROUND In several countries, contact tracing apps (CTAs) have been introduced to warn users if they have had high-risk contacts that could expose them to SARS-CoV-2 and therefore could develop COVID-19 or further transmit the virus. For CTAs to be effective, sufficient critical mass of users is needed. Until now, adoption of these apps in several countries has been limited, resulting in questions on which factors refrain app uptake or stimulate app use discontinuation. OBJECTIVE This study investigates individuals' reasons for not using or stop using a CTA, more particularly the app Coronalert. Users' and nonusers' attitudes towards the app's potential impact was assessed in Belgium. To further stimulate interest and potential use of a CTA, the study also investigated population's interest for new functionalities. METHODS An online survey was administered in Belgium, to a sample of 1,850 respondents aged 18 to 64. Data were collected between 30 October and 2 November 2020. Sociodemographic differences were assessed between users and nonusers. Both groups' attitude towards CTAs potential impact and their acceptance of new app functionalities were analysed. RESULTS Our data show that 64.9% (1201/1850) of our respondents were nonusers of the CTA under study (individuals who did not install the app, downloaded the app but did not activate is, uninstalled the app). While we did not find any sociodemographic differences between users and nonusers, attitudes towards the app and its functionalities seemed to differ. The main reasons for not downloading and using the app are a perceived lack of advantages (31.1%, 308/991), worries about privacy (29.3%, 290/991) and, to a lesser extent, not having a smartphone (18.5%, 183/991). Users of a CTA agree more on the potential of such apps to mitigate the consequences of the pandemic. Overall, nonusers find the possibility of extending the CTA with future functionalities less acceptable than current users. However, also among users, acceptability tends to differ. Among users, functionalities relating to access and control, such as digital certificates or 'green cards' for events, were less accepted (55.2%, 358/649) than functionalities focusing on informing citizens about the spread of the virus (69.8%, 453/649) or making an appointment to get tested (80.9%, 525/649). CONCLUSIONS Our results show that current users are more convinced of the CTA's utility and more inclined to accept new app features then nonusers. Moreover, nonusers have more CTA related privacy concerns. Therefore, to further stimulate app adoption and use its potential advantages and privacy-preserving mechanisms, need to be stressed. Building further knowledge on forms of resistance among nonusers is important to respond to these barriers through the app's further development, related policy, and communication campaigns. CLINICALTRIAL