Institute for Implementation Science in Healthcare, University of Zurich, Zurich, Switzerland.
Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland.
JMIR Public Health Surveill. 2021 Dec 6;7(12):e30004. doi: 10.2196/30004.
Mitigation of the spread of infection relies on targeted approaches aimed at preventing nonhousehold interactions. Contact tracing in the form of digital proximity tracing apps has been widely adopted in multiple countries due to its perceived added benefits of tracing speed and breadth in comparison to traditional manual contact tracing. Assessments of user responses to exposure notifications through a guided approach can provide insights into the effect of digital proximity tracing app use on managing the spread of SARS-CoV-2.
The aim of this study was to demonstrate the use of Venn diagrams to investigate the contributions of digital proximity tracing app exposure notifications and subsequent mitigative actions in curbing the spread of SARS-CoV-2 in Switzerland.
We assessed data from 4 survey waves (December 2020 to March 2021) from a nationwide panel study (COVID-19 Social Monitor) of Swiss residents who were (1) nonusers of the SwissCovid app, (2) users of the SwissCovid app, or (3) users of the SwissCovid app who received exposure notifications. A Venn diagram approach was applied to describe the overlap or nonoverlap of these subpopulations and to assess digital proximity tracing app use and its associated key performance indicators, including actions taken to prevent SARS-CoV-2 transmission.
We included 12,525 assessments from 2403 participants, of whom 50.9% (1222/2403) reported not using the SwissCovid digital proximity tracing app, 49.1% (1181/2403) reported using the SwissCovid digital proximity tracing app and 2.5% (29/1181) of the digital proximity tracing app users reported having received an exposure notification. Most digital proximity tracing app users (75.9%, 22/29) revealed taking at least one recommended action after receiving an exposure notification, such as seeking SARS-CoV-2 testing (17/29, 58.6%) or calling a federal information hotline (7/29, 24.1%). An assessment of key indicators of mitigative actions through a Venn diagram approach reveals that 30% of digital proximity tracing app users (95% CI 11.9%-54.3%) also tested positive for SARS-CoV-2 after having received exposure notifications, which is more than 3 times that of digital proximity tracing app users who did not receive exposure notifications (8%, 95% CI 5%-11.9%).
Responses in the form of mitigative actions taken by 3 out of 4 individuals who received exposure notifications reveal a possible contribution of digital proximity tracing apps in mitigating the spread of SARS-CoV-2. The application of a Venn diagram approach demonstrates its value as a foundation for researchers and health authorities to assess population-level digital proximity tracing app effectiveness by providing an intuitive approach for calculating key performance indicators.
感染传播的缓解依赖于旨在预防非家庭接触的靶向方法。数字接触追踪应用程序的接触追踪已在多个国家广泛采用，因为与传统的手动接触追踪相比，它具有更快、更广泛的追踪速度和广度的优势。通过引导式方法评估用户对接触者通知的反应，可以深入了解数字接触追踪应用程序使用对管理 SARS-CoV-2 传播的影响。
本研究旨在展示使用韦恩图来研究数字接触追踪应用程序的接触者通知及其后续缓解措施在瑞士遏制 SARS-CoV-2 传播方面的贡献。
我们评估了来自瑞士全国性面板研究（COVID-19 社会监测）的 4 个调查波次（2020 年 12 月至 2021 年 3 月）的数据，该研究纳入了（1）未使用瑞士新冠病毒接触者追踪应用程序的瑞士居民、（2）使用瑞士新冠病毒接触者追踪应用程序的瑞士居民和（3）收到接触者通知的瑞士新冠病毒接触者追踪应用程序使用者。应用韦恩图方法描述这些子人群的重叠或不重叠，并评估数字接触追踪应用程序的使用及其相关的关键绩效指标，包括采取措施预防 SARS-CoV-2 传播。
我们纳入了来自 2403 名参与者的 12525 次评估，其中 50.9%（1222/2403）报告未使用瑞士新冠病毒数字接触追踪应用程序，49.1%（1181/2403）报告使用瑞士新冠病毒数字接触追踪应用程序，2.5%（29/1181）的数字接触追踪应用程序使用者报告收到接触者通知。大多数数字接触追踪应用程序使用者（75.9%，22/29）在收到接触者通知后采取了至少一项推荐措施，例如进行 SARS-CoV-2 检测（17/29，58.6%）或拨打联邦信息热线（7/29，24.1%）。通过韦恩图方法评估缓解措施的关键指标显示，30%的数字接触追踪应用程序使用者（95%CI 11.9%-54.3%）在收到接触者通知后也检测出 SARS-CoV-2 阳性，这比未收到接触者通知的数字接触追踪应用程序使用者（8%，95%CI 5%-11.9%）高 3 倍以上。
收到接触者通知的 4 个人中有 3 个人采取了缓解措施，这表明数字接触追踪应用程序在减轻 SARS-CoV-2 传播方面可能发挥了作用。韦恩图方法的应用展示了其作为研究人员和卫生当局评估人群层面数字接触追踪应用程序效果的价值，为计算关键绩效指标提供了直观的方法。
