Digital contact tracing technology in the COVID-19 pandemic: a systematic review

Introduction The COVID-19 pandemic prompted public health teams across the world to emphasize case identification, contact tracing, and isolation in outbreak management strategies. Contact tracing was advanced by global access to mobile phones to develop and implement digital contact tracing (DCT) technology with the objective of increasing the rate of contact tracing while reducing the resources required.Purpose This study aimed to describe the DCT technology used during the COVID-19 pandemic across the world, and to identify differences and similarities between characteristics and uses.Methods This review followed the PRISMA (2020) guidelines for systematic reviews. Literature searches were conducted using Embase, MEDLINE, and PubMed and were restricted to English studies published between 2019 to 2023. Studies were excluded if they did not report findings for DCT during COVID-19, did not provide data for technology characteristics or outcomes, or were a study design listed for exclusion.Results Sixty one studies were included in the review producing results for 147 digital contact tracing technologies across 83 countries. The majority of digital contact tracing (DCT) technologies are government-owned (75.6%), primarily developed for COVID-19 tracing (96.4%). Bluetooth is the most favored technology (70%) used in their development, followed by GPS (30%) and QR codes (22%). Applications are the preferred platform (90.9%), with a few using applets (6.3%) and wearable devices (1.4%). Only 2 DCT technologies have achieved over 100 million downloads or uses (3.1%). Most DCTs fall into the 1-9.99 million downloads range (27.7%) and 10,000-99,999 downloads (20%). The majority of DCTs are voluntarily used by the population (63.6%), while 27.3% are mandated for use.Conclusions Digital contact tracing technologies were developed and implemented globally as a strategy in emergency outbreak management to reduce the spread of disease. This review describes the use of DCT across the world by identifying key features and characteristics that will serve as a lesson learned for improvement of existing DCT technologies for other emergency response outbreak management.