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“Low risk”, “no risk encounters”: This has been reported by the Corona Warning App from the Robert Koch Institute (RKI) to most users for weeks.
Until mid-December, on the other hand, the app regularly displayed low-risk, reassuringly green encounters for many users - especially when they moved around in an urban environment, used the bus or train and went shopping.
But that ended on December 18th.
Because there was an update for the app on the users' phones, with which the calculation of the risk of infection was fundamentally changed.
Since then, the app has been silent.
Many users are surprised, for example on Twitter: More than 600 users responded to a request from user “Toto” at the beginning of January.
"I suddenly have zero risk contacts since around mid-December," comments technology journalist Stephan Dörner.
"Since the update dead pants despite staying at 3 airports (waiting areas, queues, lounges), in 4 flights and min.
2 train journeys, ”writes Leeor A. Engländer.
How proportionate is the 15-kilometer rule?
Anyone who lives in a corona hotspot should not be able to move further than 15 kilometers from their place of residence in the future.
Prof. Volker Boehme-Neßler explains how this measure is to be assessed under constitutional law.
Source: WORLD
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The answer lies in Update 1.9 of the Corona Warning app, because with it SAP - the RKI's program partner for the app - switched to a completely new method for determining the risk of infection.
The new software should now measure much more precisely and take into account more factors, and it comes directly from Apple and Google.
The "Exposure Notification Framework 2.0" uses the phones' Bluetooth receivers to record the distance and duration of encounters more precisely - only if the signal from a counterpart has been measured for over ten minutes with a defined signal strength of over -73 Db the encounter as relevant.
At the same time, new data are to be incorporated into which a risk value is calculated, the so-called "Transmission Risk Level".
To calculate this, app users who tested positive should provide more precise information about their risk profile and symptoms such as coughing and sneezing with precise times when the symptoms started.
If an app user who tested positive was already coughing at the time of an encounter, the level is higher - the app warns from level 3.
"With the new calculation, we are able to better and more precisely filter out encounters under ten minutes and those that are not in the immediate vicinity," explains a SAP spokeswoman.
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The low-risk encounters that have been displayed so far now fall off the grid.
But they are still stored in the depths of the operating system, as the SAP spokeswoman explains.
If you want to see them, you can click on the individual checks under Settings -> Encounter records -> Active -> Encounter reviews and see the number under a matching key.
The conversion to the new technology was developed under the leadership of Apple and Google for all warning apps internationally.
The Robert Koch Institute, however, can still determine how strictly the app interprets the encounters and from what duration of the encounter the algorithm sounds the alarm.
The RKI experts also continue to assess the symptoms.
How useful the warning app works in everyday use, however, remains questionable: So far, only a good 24 million people in Germany have installed the app on their smartphones.
Asian countries such as Singapore or South Korea have much higher rates with their apps.
So that the warning app can actually prevent chains of infection far-reaching, between 60 and 80 percent of all people in Germany would have to use the app, depending on the study situation.
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Researchers from the Humboldt University of Berlin and the Ruhr University Bochum have investigated which population groups are most likely to use the Corona warning app.
To do this, they used data from a non-representative online diary study on Covid-19 that has been carried out since mid-March of last year and in which 1972 people from all over Germany between 18 and 88 years of age took part.
Since the app first appeared, participants have been asked whether they have installed it on their smartphones.
1291 people said they used the app.
They said there were no reasons against the app and the benefits outweigh the risks.
They also believed the app would help contain the pandemic.
According to the study, app users mainly include people who belong to a risk group as well as younger people.
The 681 participants who stated that they did not install the app justified this primarily with concerns about data protection.
They also questioned whether the app could really help contain the pandemic, or said they did not own a compatible smartphone.
According to the study, participants who refuse to use the app are older, female and healthier on average.
Since the app was launched, the federal government and data protectionists have tried again and again to dispel concerns that users could be digitally monitored.
They hoped that this would encourage even more citizens to use the app.
But for a few weeks now, the number of installations has not increased significantly, at least according to Google's app store statistics.
That could change if the RKI would integrate new functions such as an appointment scheduling function for vaccination or testing.