The widespread popularity of mobile applications and their practicality made them the perfect vehicle to deliver capillary contact tracing services. As the COVID-19 virus is transmitted by proximity to infected individuals, a large number of the contact tracing apps launched allowed for wireless data exchange between devices via Bluetooth technology. During the last quarter of 2021, the NHS COVID-19 app has generated more than 6.36 million downloads, while the German CovPass saw around 6.29 million downloads, and the Indian Aarogya Setu generated 2.56 million downloads in October 2021 alone.
Contact tracingIn February 2020, China was the first country to officially roll out a mobile app feature with a contact tracing system. The “Health Code” integration, which was developed by Tencent and Alipay, launched first in Hangzhou but was soon made available in more municipalities via the mobile social media app WeChat and mobile payment app Alipay. Users were asked to scan QR codes positioned in numerous locations to help track the COVID-19 infection spread. The mobile integration calculated users’ risk exposure based on their movements as well as on self-reported health parameters and eventual symptoms, generating a personal QR code: green allowed for freedom of movement, while with yellow or red users were prompted to isolate and take measures.
In other parts of the world which lacked such encompassing mobile ecosystems as WeChat, creating new mobile applications with similar features was deemed as the most suitable solution. India was the second country to lunch a contact tracing app: the Aarogya Setu (‘bridge to health’) mobile app was developed by the Government of India and its Ministry of Health. Installation was mandated for government employees and those in the private sector. Despite the large numbers of downloads, as of May 2021, there were notable geographical disparities in the app reach. In the states of Chandigarh and Delhi, the Aarogya Setu app saw a population reach of 48.1 percent and 45.9 percent, respectively. By comparison, the state of Meghalaya and the state of Lakshadweep saw a population reach of 4.1 percent and less than three percent, respectively.
In April 2020, Apple and Google joined forces to develop complementary application programming interfaces (API) that could be interoperative and work with Bluetooth technology for a seamless automated contact tracing feature. Several countries, including Austria, Canada, Italy, Germany, Japan, and Saudi Arabia opted to develop their official apps using the Exposure Notifications System (ENS) made available by the two tech giants.
Users reception and vaccine verification featuresIn Europe, Italy was the first country to see its coronavirus infection numbers skyrocket in 2020. The mobile app Immuni was launched in early June of the same year as a contact tracing app, amassing 3.22 million downloads during the second quarter of that year. The German Corona WarnApp was also launched in June 2020, and has amassed more than 15 million cumulative downloads from the Apple App Store, and approximately 19.3 million downloads from the Google Play Store as of September 2021.
In France, the TousAntiCovid mobile app saw approximately 3.92 million downloads during the last quarter of 2021, while in the United Kingdom, the NHS COVID-19 mobile app reached 29.69 million cumulative downloads at the end of the same year. In the United States, contact tracing apps did not experience a linear development, as each state that opted to make usage of a mobile contact tracing solution ended up creating a specific app for the purpose.
The reception of contact tracing apps was ambivalent in numerous countries that implemented the system. However, with the rollout of vaccination plans in 2021, coronavirus-related apps became even more prominent for users, due to the introduction of vaccine verification systems. COVID-19 digital travel passports, which are passes attesting individuals’ vaccination status, recovery, or negative test results, have become indispensable for international travels. In the United States, the most popular apps used to give proof of COVID-19 vaccination reached 1.6 million downloads in August 2021 alone. In Italy, as of February the 1st, 2022, approximately 186.98 million digital "green pass” certifications were downloaded via the IO mobile app, and almost 20 million using the Immuni mobile app. In Germany, the CovPass Check app and the CovPass app, which are primarily intended to display COVID-19 vaccination status, generated 2.25 million and 6.2 million downloads, respectively.