The SwissCovid Digital Proximity Tracing App after one year: Were expectations fulfilled?

Recent evidence on the SwissCovid app in Switzerland and digital proximity tracing (DPT) apps in an international context reveals DPT apps to be effective at mitigating non-household spread. Future pandemic management through DPT apps requires more investment in resources to advance digitalization in healthcare, educate relevant stakeholder groups and address concerns of user privacy and principles of voluntariness.

The SwissCovid tracing app was launched in Switzerland on 25 June 2020, with several objectives to mitigate the spread of the SARS-CoV-2 virus: (1) faster notification of exposed contacts, (2) communication of possible exposure to non-household contacts and (3) complementation of manual contacts tracing efforts, especially when they reach capacity limits.

Paola Daniore, who is part of Prof von Wyl’s team at IfIS, collected evidence on the effectiveness of digital proximity tracing (DPT) apps in Switzerland and in an international context, and assessed the implications of DPT apps on future pandemic management in a recent publication in the journal Swiss Medical Weekly Link

Some key messages and numbers:

- As of June 2021, almost 1 year after its launch, the SwissCovid app has been downloaded more than 3.1 million times and has approximately 1.7 million active users.

- Swiss studies (UZH, Uni Bern) evidenced that 69% of all persons with an exposure notification (EN) sought testing for COVID-19. Persons who sought testing after receiving an EN revealed more likely to test positive for COVID-19 than those without an EN.

- An analysis from the Zurich SARS-CoV-2 Cohort study suggested that contacts notified by the SwissCovid app about their non-household risk exposure entered quarantine on average 1 day earlier than contacts who did not receive a notification.

- International comparisons demonstrate that the SwissCovid app reached an adoption rate comparable to those of other countries that use DPT apps. Also the frequency of ENs sent upon contact with a person tested positive for SARS-CoV-2 was comparable.

- The SwissCovid app led to an estimated nationwide identification of approximately 500 to 1’000 persons per month who tested SARS-CoV-2-positive after receiving an EN between January and April 2021, when an average of approximately 50’000 persons tested positive each month.

⇒ Current evidence indicates a relevant impact of the SwissCovid app on notifying persons at risk and contributing to pandemic mitigation during months with higher infection rates, especially in the context of non-household spread.