Corona app: as effective as all health departments combined?

The official Corona warning app (CWA) has taken a lot of criticism since its launch a year ago: "Unfortunately, the app has been a zunsuspecting tiger", said Bavaria's premier, for example Markus Soder (CSU) in conversation with our editors. After all: That was in October.

Updates followed, the developers from Telekom and SAP fine-tuned the application, and in the meantime the app, which has been downloaded around 28 million times, has many functions that critics had long demanded; for example, the ability to check in at restaurants and events.

Behind all this, however, is the fundamental question: How effective is this software, for which the German Federal Ministry of Finance is spending up to 69 million euros has calculated? How many users actually enter a positive test on their smartphone and warn other people?

Corona warning app: RKI and BMG with first data on effectiveness

The Federal Ministry of Health (BMG) and Robert Koch Institute (RKI) have celebrated their first birthday (16. June) of the Corona Warning App as an opportunity to take stock of the first interim results. It's not easy, because the Contact tracking of the app anonymous and decentralized runs. The program's creators therefore resorted to data that users voluntarily shared. For example, a survey from March to May 2021, in which users with the warning "increased risk" could participate. In addition, since March 2021, users have been able to make a data donation, i.e., answer questions about the app and how they use it.

In a blog post, however, the developers point out that this is an initial, preliminary evaluation. "A detailed processing and analysis of this data will be regularly in greater detail in the coming weeks," they write. But already show tendencies.

  • Around 73 percent were surprised by the display of increased risk. The developers interpret this as an indication that the app also frequently warned people outside the family or circle of colleagues, where a risk might be easier to assess without software.
  • A total of 61 percent of users who registered a positive test result via the app also alerted others by sharing the finding.
  • The majority of users actually had themselves tested after a red warning, according to the survey.

According to the RKI, nearly half a million people (472.900), the Corona warning app alerts others of a dangerous risk encounter. As a result, according to information from government circles, in over 200.000 cases of infection chains interrupted, writes the German Press Agency. The number of relevant warnings could be much higher, however, if all users of the app who tested positive were to enter this fact. Initially, however, not even 40 percent of those affected dared to trigger this chain of alarms.

As reported by the specialist portal "our site", according to RKI estimates 110.000 to 230.000 CWA users have tested positive after a red warning and thus been pulled out of infection chains. This corresponds "approximately to the positive rate achieved with analogous Contact tracing can be observed," according to "our site" in a paper from BMG and RKI. That, in turn, would mean: The contribution that the Corona app makes to the Pandemic Fight The RKI estimates that the vaccination rate is about as high as that of all health authorities combined