Cross-national survey on the termination of Digital Contact Tracing apps: Have we killed the goose that lays the golden eggs?
Yuki Kamei, Wataru Tanabe, Manabu Ichikawa, Takashi Okumura · Informatics in Medicine Unlocked · 2025
During the COVID-19 pandemic, Digital Contact Tracing (DCT) tools were deployed worldwide as critical Non-Pharmaceutical Interventions aimed at controlling virus transmission. While simulation studies and some real-world evaluations suggested their potential effectiveness, many were discontinued before the pandemic ended. The reasons behind these decisions and the full lifecycle of these applications remain poorly documented. To address this gap, we conducted a cross-national multi-lingual survey on the status and discontinuation of contact tracing apps. We developed a registry of countries and their DCT apps by combining existing study results with new online surveys. For each app, we manually collected data on operational status, reasons for termination, and contextual factors. A qualitative analysis was then conducted to identify common patterns and their potential association with national pandemic trajectories. The registry includes 184 DCT apps across 158 countries and regions. Among these, 45.7% had been terminated by the time of analysis. Termination reasons were categorized into five primary areas: pandemic stage, government policy shifts, privacy concerns, technical challenges, and user acceptance issues. Notably, apps that did not use the Google/Apple Exposure Notification framework were more likely to face privacy and technical barriers, contributing to early shutdowns. We also observed cases where app termination was followed by infection surges. This study showed that effectiveness and continuity of DCT apps depend not only on technical performance but also on strategic alignment with infection control measures and adequate supporting resources. Based on the findings, Future DCT systems should be designed to remain viable throughout pandemics. • DCT apps were deployed worldwide but their termination status remains mostly unclear. • Among 184 DCT apps released during the pandemic, 45.7% have already been terminated. • DCT terminations were due to policy, privacy, tech, trust, and epidemic-stage factors. • In some countries, infection rates increased following the termination of DCT apps. • Toward effective DCT, sustained use beyond pandemic periods is considered essential.