Table 4.
Availability and use.
| App | Country | Release date | Downloads, n (% of population) | Date reported | Source type |
| Corona Warn App | Germany | June 16, 2020 | 25.4 million (30.6%) | February 11, 2021 | Official [40] |
| TousAntiCovid | France | June 2, 2020 | 11 million (16.4%) | December 8, 2020 | Official [43] |
| Immuni | Italy | June 15, 2020 | 10.3 million (17.06%) | February 22, 2021 | Official [44] |
| Radar COVID | Spain | August 2020 | 7.03 million (17%) | February 14, 2021 | Official [45] |
| Koronavilkku | Finland | August 31, 2020 | >2.5 million (45.3%) | November 5, 2021 | Official [46] |
| NHSa COVID-19 | England and Wales | September 24, 2020 | 21.8 million (36.7%) | February 10, 2021 | Official [47] |
| TraceTogether | Singapore | March 20, 2020 | 4.2 million (73.7%) | February 23, 2021 | Official [34] |
| Self-Diagnosis app | South Korea | March 2020 | >500,000 (0.96%) | February 23, 2021 | Google Play Store [61] |
| Self-Quarantine app | South Korea | March 2020 | >500,000 (0.96%) | February 23, 2021 | Google Play Store [62] |
| Coronavirus-SUSb | Brazil | August 1, 2020 | 10 million (4.77%) | December 8, 2020 | Official [48] and press [63] |
| Various integrated tracing functions in apps (eg, WeChat) | China | February 2020 | —c | — | — |
aNHS: National Health Service.
bSUS: Sistema Único de Saúde.
cNot available.