Navigation and service

Use of cookies

Cookies help us to provide our services. By using our website you agree that we can use cookies. Read more about our Privacy Policy and visit the following link: Privacy Policy

OK

Interrupt chains of infection digitally with the Corona-Warn-App

Corona-Warn-App is an important component of pandemic control

Corona-Warn-App. Source: Bundesregierung

A key element in the fight against any pandemic is to interrupt the chains of infection. The Corona-Warn-App can make an important contribution to this and can support the central work of the health authorities in tracing contacts.

The health authorities use information from persons who tested positive for SARS-CoV-2 to identify people whith whom they were in contact, who may also test positive in order to contain the spread of the pathogen.

The Corona-Warn-App is an important supplement because it helps to map exposures and supports the public health authorities. Encounters with strangers in public spaces are also recorded and potentially exposed individuals are identified faster, because this happens automatically in the Corona-Warn-App.

Contact tracing by the health authorities remains necessary, e.g. to identify or inform people who do not use the app or do not have a smartphone. However, contact tracing and notification via the App does not replace the reporting channels specified by the German Infection Protection Act.

Since the release of the Corona-Warn-App in June 2020, key figures on the use of the hotlines are now also available.

Every user of the Corona-Warn-App makes an important contribution to the further containment of the pandemic. We thank the citizens for their interest and participation!

The App is published by the Robert Koch Institute on behalf of the German government.

Important note: Your data is safe. The Corona-Warn-App meets the highest standards of data protection and works with very little data. However, this means that only a limited amount of data is available for evaluating its use.

Overview of new functionalities

Version 1.9 of the Corona-Warn-App, released on December 16, 2020, brings two major improvements:

Transition to the advanced interface (version 2 of the Exposure Notification Framework, ENF) from Apple and Google, on which the Corona-Warn-App is based.

Adjustments to process steps from scanning the QR code to sharing diagnosis keys.

Specifically, the following has been changed: For multiple increased-risk encounters (red), users will now see the date on which the last increased-risk encounter occurred.

In addition, the epidemiological risk assessment is now even more accurate: now, several - individually considered - low-risk encounters (green) can lead to an increased risk (red): Depending on infectiousness, 15-30 minutes of low-risk encounters (green) become an increased-risk encounter (red).

The display also changes. Users are now shown the number of days on which risk encounters have occurred, but no longer the number of encounters.

With the changeover to ENF 2.0, it is no longer a single encounter that is decisive for the risk assessment, but the sum of the risk minutes per day. Thus, even multiple, short-term risk encounters can lead to an increased risk.

Further details on the risk calculation are, as before, documented on GitHub: https://github.com/corona-warn-app/cwa-documentation/blob/master/images/risk_calculation/risk_calculation_enf_v2_overview.pdf.

Furthermore, the process from scanning the QR code for automatic transmission of the test result to sharing the diagnosis keys has been improved. This is to encourage users to share their diagnosis keys and alert others following their positive test result. Together with Google and Apple, those involved in the project are working to further improve the process.

As with the previous version, this update will be delivered in a controlled rollout. This means: the app will be made available to users in a staggered manner so that irregularities in functionality can be responded to immediately with a bug fix.

You can read more details in the blog of the development teams: https://www.coronawarn.app/de/blog/2020-12-16-corona-warn-app-version-1-9/

To download the Corona-Warn-App

Corona-Warn-App for iOS
Corona-Warn-App for Android

You do not need the verification hotline when installing the App. Please only call the hotline if you have a positive test result for SARS-CoV-2.

Status displays in the Corona-Warn-App

The Corona-Warn-App has three different status indicators: “unknown risk” (grey), “low risk” (green) and “increased risk” (red).

With the status display "unknown risk", the risk determination was not active long enough, so no risk calculation could be performed.

The status display "low risk" either indicates that the app has not identified any encounters with another corona-positive person documented in the app, or that the relevant threshold values have not been exceeded.

If the app displays a "low risk" status and at the same time lists risk encounters, this means that you had contact with a corona-positive person, but the encounter was so short or the distance so great that there was most likely no increased risk of infection. In this case, you do not have to do anything, but you will again be familiarised with the applicable rules of distance and hygiene.

If the status display "increased risk" appears on the smartphone, you have had at least one encounter within the last 14 days with a person who has now tested positive. You will be asked to reduce personal contacts and to contact your family doctor's practice or the public health department. They will then decide whether a PCR test is to be performed.

Why the Corona-Warn-App is important

The corona pandemic has not yet been overcome, despite the recent declining number of cases. As long as no vaccine is available, a new wave of infection cannot be ruled out. The Corona-Warn-App helps to contain the pandemic by interrupting chains of infection.

Other effective measures include:
the daily wearing of masks,
practicing hand hygiene,
observing coughing and sneezing etiquette,
observing the principle of social distancing,
ventilate enclosed spaces,
as well as supplementary guidelines and recommended actions for medical personnel.

Answers to frequently asked questions about the Corona-Warn-App

General questions

Why the Corona-Warn-App is important

The corona pandemic has not yet been overcome. Currently, the number of transmissions in the population in Germany is high (daily situation reports: www.rki.de/covid-19-en). The Corona-Warn-App helps to contain the pandemic by interrupting chains of infection.

The App is published by the Robert Koch Institute for the German government. It helps to additionally map out possible exposures with corona-positive persons. In this way, it supports the work of the health authorities and can also contribute to controlling the test capacities for SARS-CoV-2.

The Corona-Warn-App is an important component of an overall strategy to combat the pandemic, which consists of numerous other infection control measures. These include the wearing of masks daily, practicing hand hygiene, observing coughing and sneezing etiquette, observing the principle of social distancing as well as supplementary guidelines and recommended actions for medical personnel.

Date: 18.01.2021

How using the Corona-Warn-App helps to contain the pandemic

If people are quickly informed about a possible infection, they can react quickly to protect themselves and others. The App therefore helps people to protect their family, friends and the whole community.

Until now, health authorities have used information from persons who tested positive for corona to trace the people who they were in contact with in order to contain the spread of the pathogen. The Corona-Warn-App is an important support as it helps to depict exposures in addition to the public health authorities, and it identifies and notifies people who have had an epidemiologically relevant encounter with a corona-positive person faster than with classical tracing. It also helps to reduce the time delay between when a person tests positive, and the identification and information of their contacts. The Corona-Warn-App can also records encounters with strangers in public places such as on public transport, or while shopping in a supermarket, which was not possible before.

Date: 10.09.2020

How the Corona-Warn-App works

The Corona-Warn-App uses Bluetooth technology to measure the distance between people who have installed the App and enables the smartphone to remember these encounters. To do so, the devices exchange temporary encrypted random codes (Bluetooth ID) with each other. These temporary random codes are cryptographically derived several times per hour from the random device key of the smartphone. The random device keys (or daily keys) are generated anew every day.

The Corona-Warn-App thus uses two types of random codes, a random device key or day key, and a short-lived random Bluetooth ID, which is derived from the random device key and exchanged between neighboring mobile devices. Both random codes cannot be assigned to a specific person without additional knowledge and are automatically deleted when they are 14 days old.

If users of the App test positive for the corona virus, they can choose to pass on their own device keys for matching. In this case, the device keys of the user who tested positive for SARS-CoV-2 are uploaded to the Corona-Warn-App server. All active Corona-Warn-Apps download the so-called positive identifiers published on the Corona-Warn-App-Server several times a day and transfer them collectively to the operating system via an interface. The operating system checks whether there are received and recorded random codes which match a random code of the user tested positive for SARS-CoV-2.

In case of a match, the risk of transmission is determined in a multi-stage procedure and if defined thresholds have been exceeded, the user is informed of the possible risk assessment by means of a notification. At no time does this procedure allow conclusions to be drawn about the user or the location.

Date: 10.09.2020

How the Corona-Warn-App informs about a possible risk of infection

The Corona-Warn-App informs the users by message if they have been near a Corona-positive person for a certain time in the past. Depending on the type of encounter with a Corona-positive person, the user is informed of the risk of infection. The App differentiates between low and increased risk, and at the same time gives recommendations for action.

Date: 10.09.2020

Why user data is safe and secure

The Robert Koch Institute plays a dual role in the Corona-Warn-App: It makes a professional contribution to the design of the App, and as the publisher, it is also responsible for carefully checking the requirements for data protection and data security.

The data of the users of the Corona-Warn-App are always safe and users remain pseudonymous at all times. Users who register in the App do not have to provide personal data (such as e-mail address and name).

Decentralized data storage on the devices themselves and full pseudonymization guarantee the highest level of data protection. All data on encounters with other users is encrypted and stored exclusively on the user's own smartphone.
In the event of an infection, the user decides whether his/her own random codes are uploaded to the Corona-Warn-App-Server. This allows the App users to assess the risk and in case of a relevant encounter, to send a corresponding reporting of positive risk result.

The app does not have access to data that makes a user identifiable. One thing is certain: A person tested corona-positive, does not find out who is being informed. Those who are informed do not know who the Corona-positive person is. Technical and organizational measures are taken to prevent misuse of the infection status report via the app.

Date: 10.09.2020

Why user data is safe and secure

A publication of the Corona-Warn-App in App Stores outside of Germany is currently only possible after a case-by-case examination due to legal reasons. In case of publication in international App Stores, the law of the respective country must be considered and applied to the Corona-Warn-App. This applies in particular to data protection, any necessary claims for information by local authorities, and other contractual and consumer protection regulations.

The Robert Koch-Institute as publisher of the app will initiate this individual case examination and make the App available via the respective App stores after successful examination.

For the following European countries this legal check has already been done and the App is available in the respective App Stores:

  • Austria
  • Belgium
  • Bulgaria
  • Croatia
  • Cyprus
  • Czech Republic
  • Denmark
  • Finland
  • France
  • Greece
  • Hungary
  • Iceland
  • Ireland
  • Italy
  • Latvia
  • Lithuania
  • Luxembourg
  • Malta
  • the Netherlands
  • Norway
  • Poland
  • Portugal
  • Romania
  • Slovakia
  • Slovenia
  • Spain
  • Sweden
  • Switzerland
  • United Kingdom

The App is currently under review for other countries and will be released in the App Stores step by step. The Robert Koch Institute asks for your co-operation as it cannot provide any information on specific countries and the status of their release during the ongoing review process.

Date: 10.09.2020

How to use the Corona-Warn-App in (European) countries

The Corona-Warn-App is aimed at those who live permanently in Germany as well as those who stay here temporarily, e.g. as commuters or tourists. For commuters and tourists travelling to Germany, the app has also been made available on foreign app stores.

The app also works in other European countries and can already display risk notifications to users of the German app. Nothing needs to be changed in the smartphone's regional settings when traveling abroad. Important note: The functions connected to it, such as automatic notification of a test result via QR code, are tailored to the requirements of the German healthcare system. If a user from abroad takes a test that has been analyzed in a German laboratory, it is possible that he/she will also receive the result automatically via the app.

Additionally, only one warning app can be active at a time due to the API interface of Google/Apple. Therefore, it should be decided in each individual case which app is the most useful at the moment. To ensure the interoperability of the applications it is necessary that the apps have the same standards.

Regarding the interoperability of the warning apps in Europe: According to the plans of the EU Commission, the European gateway server required for the cross-border use of the Corona-Warn-App is to be set up in autumn. Corresponding warnings can then be exchanged between the various national Corona-Warning-Apps across borders. For this purpose, the technical specifications have been agreed among the EU user states and a European legal adaptation has already been made.

The apps of these countries have already been connected via the European gateway server:

  • Italy
  • Ireland
  • Croatia
  • Denmark
  • Latvia
  • Spain
  • Poland

Date: 26.11.2020

Why the weekly update "COVID-19 exposure log" is not an exposure notification of the Corona-Warn-App

The report "COVID-19-exposure logging" which appears once a week is not a message of the Corona-Warn-App.

It is an operating system-specific, purely technical function that informs about all encounters with App users who have tested positive for SARS-CoV-2. However, it does not take into account whether the encounter was critical according to the Robert Koch Institute's algorithm or not.

It is therefore insufficient for an exact exposure logging, as it also indicates encounters that are below the thresholds defined by the Robert Koch Institute to determine an increased risk. For example, this operating system-specific function also reports encounters where the distance was more than 8 meters or which lasted only a few minutes.

In contrast, the risk assessment in the Corona-Warn-App is based on the established criteria for "conventional" contact person detection (encounters of at least 15 minutes fewer than 2 meters). A reliable exposure logging takes place exclusively in the Corona-Warn-App under the scientific framework of the Robert Koch-Institute. You can check your current risk status directly in the Corona-Warn-App.

Date: 15.09.2020

Epidemiological questions

How the risk factors are calculated

During the development of the App, the Robert Koch Institute contributed its scientific expertise on how encounters, where there was a risk of infection, are categorized via the app and what measures users of the app are advised to take in case they have had an encounter with a person who has tested positive for SARS-CoV-2.

For an encounter to be assessed as a possible exposure by the Corona-Warn-App, it must have been epidemiologically relevant. This means, there must have been a risk of infection. The risk assessment in the App is based on a complex model, in the development of which various factors have been incorporated.

The risk of transmission is assessed in a four-step procedure. This includes the evaluation of:

  • How long ago the user met a corona-positive person,
  • How long the contact lasted,
  • How close the persons came to each other and
  • The transmission risk of the corona-positive person.

The result is a risk score which is displayed to the user as a message. If this "risk score" exceeds a threshold, the user receives a warning on the screen.

Date: 10.09.2020

Why are only the contacts of the last 14 days recorded and possibly warned?

In general, a distinction is made between whether a infectious person was already symptomatic at the time of transmission to another person, whether he or she had not yet developed any symptoms or whether he or she never became symptomatic later (asymptomatic infection). In addition, a considerable number of people are also likely to be infected by other, infectious individuals in the 1-2 days before their symptoms begin.

The incubation period indicates the time from the infection until the beginning of the disease. It is on average (median) at 5-6 days (range 1 to 14 days). The serial interval defines the average interval from the beginning of the illness of an infectious case to the beginning of the illness of a case infected by it. The Robert Koch Institute estimates the median serial interval for SARS-CoV-2 to be four days (interquartile interval: 3-5 days), which is supported by various studies. However, in order to cover all eventualities in the app, the range of 14 days was used. A longer period was not recommended from the point of view of epidemiologists and data protectionists.

Date: 10.09.2020

Information on how many people have been informed about an increased risk

There is no data on how many people were informed about a possible exposure with the help of the Corona-Warn-App, as the app is based on a decentralized approach.

All user data is encrypted and stored exclusively on the users’ smartphone. Neither the Robert Koch Institute, as the publisher, nor third parties have access to these data. There is no information on how many people have been informed about a possible exposure with the help of the Corona-Warn-App.

If a person using the app tests positive for the coronavirus, they can voluntarily inform other users. Then the random codes of the infected person are made available to all those who use the Corona-Warn-App.

If you have installed the app, the app will then check if you have met the person who tested positive for Corona. This check only takes place on your smartphone. If the exposure logging is positive, the app will show you - and only you - an exposure notification ("increased risk").

Date: 26.11.2020

How should the Corona-Warn-App be used by the staff of health care facilities or by the staff during activities like patient transport?

1. Treatment of patients tested positive for SARS-CoV-2 with adequate protective equipment* (prior verification via the Corona-Warn-App)

When working with people who have already been verified as a positive case via the Corona-Warn-App, no further codes are exchanged by the App and thus no new warning messages are generated. An increased risk is only given for encounters for the last 14 days before verification. After that, the code exchange function is deactivated via the app of the verified case. Thus, when working with verified positive cases, the staff is not notified of an increased risk and the app can still be used with full functionality.
(e.g. work on a station with verified COVID-19 cases)

* In the direct care of patients with confirmed or probable COVID-19 infection, at least FFP2 masks must be worn in accordance with occupational safety regulations.

2. Treatment of patients tested positive for SARS-CoV-2 without adequate protective equipment* (subsequent verification via the Corona-Warn-App)

When working with persons who can be verified as positive cases via the Corona-Warn-App afterwards, warnings are generated for contact persons retroactively for 14 days until the time of verification. According to this, when working with positive cases that can be verified retrospectively, the personnel will be notified of a exposure and possibly also an increased risk. Since the selective deactivation of the warning message for certain contacts is not possible, it is advisable in this case to deactivate the Bluetooth function during the treatment of Corona-positive tested persons, since otherwise a warning message with increased risk is the result. The warning message cannot be subsequently deactivated and cannot be differentiated from another encounter without a PPE.
(e.g. work on a station with suspected COVID-19 infection)

* In the direct care of patients with confirmed or probable COVID-19 infection, at least FFP2 masks must be worn in accordance with occupational safety regulations.

3. Treatment of patients with unexplained SARS-CoV-2 infection status by persons with adequate protective equipment*

When treating patients with an unexplained infection status with adequate protective equipment, it is advisable to deactivate the Bluetooth function. If the treating person can be verified later as a positive case, the treating personnel will otherwise be notified of an increased risk. Since, as mentioned in point 2, it is not possible to deactivate the warning message afterwards and it is no longer possible to differentiate between contact with persons with and without PPE, the app should not be used. This is the only way to send truly increased risk messages specifically through the app.
(e.g. work on a station with suspected cases of COVID-19 infection)

* In the care of patients who are not a probable or confirmed case, a medical mouth and nose protector is adequate protective equipment, provided that no aerosol generating activities are performed.

4. Treatment of patients with unexplained SARS-CoV-2 infection status by persons without adequate protective equipment*

When treating patients with an unexplained infection status without adequate protective equipment, the app can be used without any functional restrictions. If the treating person can be verified later as a positive case, the treating personnel will be notified of an increased risk. This warning message is then to be interpreted as an adequate risk message.

*In the care of patients who are not a probable or confirmed case, a medical mouth and nose protector is adequate protective equipment, provided that no aerosol generating activities are performed.

Date: 10.09.2020

Questions about the test result

How users can give their consent to the transmission of the test result in the app

In order for the test result to be automatically transmitted to the Corona-Warn-App, the user must agree to this data transmission.

To do this, the relevant field on the order sheet for the laboratory must be ticked when taking the sample for the test – after the doctor or the staff at the test center have given the appropriate information. You can find a sample of this form with the consent field here.

Muster Probenbegleitschein. Quelle: Robert Koch-Institut

After sampling, the tested person receives the lower section of the order sheet. There is a QR code printed on it, with which the test must be registered in the Corona-Warn-App. How this works is explained step by step here:

Corona-Warn-App: Registrierung eines Tests mittels QR-Code. Quelle: Robert Koch-Institut

Date: 26.11.2020

How to register a test in the app using the QR Code

When taking samples for the PCR test, the person tested receives the lower section of the order sheet for the laboratory. There you will find instructions for the registration of the test and for what to do next.

The QR code is also printed there, with which the test must be registered in the Corona-Warn-App. To do so, open the Corona-Warn-App and click the button "Inform & help" in the start screen under "Have you been tested?”. After the explanatory text there is the possibility to scan a QR code (if asked, access to the camera of the smartphone must be granted for this purpose).

If the test was registered successfully, a confirmation screen will appear with information about what to do next.

In this diagram you can see the procedure step by step: Registration of a test by QR code

Corona-Warn-App: Registrierung eines Tests mittels QR-Code. Quelle: Robert Koch-Institut

Important note: Each QR code is only valid once. If a new QR code is scanned, the previous code is deleted. An automatic transmission of the test result for the first code is then no longer possible. In all cases, the person tested will be informed of their test result by telephone or in writing by the family doctor's practice or the public health department.

If the QR code is lost or becomes unusable, the user can use the verification hotline (free call at 0800 754 0002, available 24 hours a day) to request a “teleTAN”, which can be used to enter a positive test result in the app. This is only necessary in case of a positive result.

If the user agrees to the automatic transmission of results via the Corona-Warn-App when their sample is taken, the test result will be displayed on the smartphone of the tested person as soon as it is available.

If the test result is positive, the tested person is asked to share this information with the other users of the Corona-Warn-App.

In this diagram you can see the process step by step: Sharing the positive test result in the Corona-Warn-App

Corona-Warn-App: Teilen eines positiven Testergebnisses. Quelle: Robert Koch-Institut

If the automatic transmission of the test result is not possible or if the QR code is lost, the person who tested positive can request a “teleTAN” via the verification hotline (free call at 0800 754 0002, available 24 hours a day), ‘which can then be used to enter a positive test result in the app. This is only necessary in case of a positive result.

In order to store the positive test result via “teleTAN” in the Corona-Warn-App, the button "Inform & help" must be clicked in the start screen under "Have you been tested?”. After the explanatory text there is the possibility to enter the ten-digit TAN under "TAN". In the next step, the user must then agree to pass on his or her own random codes so that others can be warned.

Date: 26.11.2020

In which cases do I get a teleTAN and from whom?
In which cases do I have to call the hotline?

If the laboratory cannot (yet) generate a QR code or if it is lost, the user can have the test verified via the telephone hotline. A teleTAN is generated in this process. The hotline is staffed by trained personnel who perform a plausibility check to prevent misuse. This teleTAN can be used to confirm a positive test result for SARS-CoV-2 in the Corona-Warn-App and thus generate warning messages. The hotline is manned by employees who speak German, English and Turkish.

Date: 10.09.2020

Why only PCR test results can be entered in the app

According to the National Test Strategy, positive results of rapid tests/antigen tests must always be confirmed by an additional PCR test. The result of the PCR test can then be stored in the Corona-Warn-App, as has been customary up to now.

Date: 26.11.2020

"Low risk" with simultaneous risk encounters - What does this status display mean

The Corona-Warn-App has three different status indicators: “unknown risk” (grey), “low risk” (green) and “increased risk” (red).

The "low risk" status indicator either shows that the app has not identified any encounters with another corona-positive person documented in the app, or that the relevant thresholds have not been exceeded.

If the app displays a "low risk" and at the same time lists risk encounters, this means that the user had contact with a corona-positive person, but the encounter was so short or the distance so great that there was most likely no increased risk of infection. The user is again familiarised with the applicable distance and hygiene rules.

Date: 26.11.2020

Receiving notification of an "increased risk" - What users should do

If the status display "increased risk" appears on the user's smartphone, the user has had at least one encounter within the past 14 days, with a person who has now tested positive.

The user is asked to reduce personal contacts and to contact the family doctor's practice or the health department, if symptoms occur. They will then decide whether a PCR test should be carried out.

Date: 26.11.2020

Who decides whether a user with an "increased risk" according to the app, should have a test for SARS-CoV-2

If a user receives a notification of an "increased risk" in the Corona-Warn-App, he/she is at the same time asked to reduce personal contacts and to contact the family doctor's practice or the public health department. These organisations will then decide whether a PCR test should be performed.

Addition: What is asked and how it is decided
If a user contacts the public health department, it is recommended for them to clarify the contact situation in a conversation - analogous to the usual procedure. For this purpose, the details of the risk notification from the app can be used, such as the number of risk encounters and the time since the last risk encounter. If possible, this is used as a basis for their categorization as a Category I or II contact and appropriate measures are taken.

Date: 09.12.2020

How to voluntarily provide information on symptoms, after a positive test result

When entering a positive test result in the Corona-Warn-App, you can - voluntarily - also enter information about symptoms. This information enables an even more precise assessment of the risk of infection, at the time of encountering another user.

If a person who tests positive confirms that he/she has symptoms, information can then be provided on these symptoms and when they started. The information about symptoms and onset of symptoms is transmitted when the test result is subsequently shared and is included in the risk calculation of the users with whom epidemiologically relevant encounters have taken place. Other users do not receive information on the symptoms of a contact person.

Date: 26.11.2020

What should I do in the Corona-Warn-App if I tested positive for SarsCoV-2?

A QR code is printed on the entry form for the laboratory sample, if the laboratories can technically provide this information. The patient receives this code in order to register his/her test in the app.

As soon as the test result is analyzed, it is automatically made available via the app and the user can then decide whether he/she wants to share this information of a positive test. The family doctor’s practice and health authority will of course also receive the results and will inform the patient. Parallel to this, the processes for the legal reporting obligations for suspected or confirmed cases run.

If the laboratory cannot (yet) generate a QR code or if it is lost, a positive test for SARS-CoV-2 result can also be confirmed with a teleTAN in the app. This teleTAN can be obtained via the verification hotline. Our service staff can be contacted around the clock at the toll-free number 0800 7540002 and will help you immediately.

To date, not all laboratories have been connected to the test result server of the Corona-Warn-App; currently 80 % of the existing laboratories in Germany are connected. We are continuing to work with laboratories to close the gaps and to upgrade and connect them all digitally to the apps test result server. Therefore it is possible that a laboratory gets the order for the test with the correct form, but has to transmit the test result to the tested person in another way.

Link to explanatory film: https://www.alm-ev.de/corona-warn-app.html [in German, only]

Date: 26.11.2020

Should I register negative and positive test results for SARS-CoV-2 into the app? What about previous test results?

A warning is generated by the app when app users confirm a positive test result for SARS-CoV-2 and enable it to warn others. In this case contact persons of the past 14 days who had a relevant contact with this person will be warned.

Therefore only positive test results for SARS-CoV-2 (PCR test) of the last 14 days should be entered into the app. Negative tests as well as tests carried out more than 14 days ago should not be entered. Negative results or past positive tests would not fulfill the goal of warning of a possible risk of infection with the Corona-Warn-App, since a potentially infectious incubation period is no longer present.

Date: 10.09.2020

Possible reasons why you cannot view your test result in the Corona-Warn-App

  1. On the form with the QR Code, the field 9 (consent of the insured) is not selected. In this case, the laboratories must not communicate the test result via the Corona-Warn-App.
  2. The laboratory is not yet connected to the test result server of the Corona-Warn-App. Currently, 70-80% of the existing test capacities in Germany are covered by the complete digital process. We are continuing to work with the laboratories to close the gaps and to connect and upgrade all laboratories for the process. Therefore it can happen that a laboratory gets the order for the test with the correct form, but has to transmit the test result to the tested person in another way.
    Furthermore, various laboratories and apps offer their own forms that are not compatible with the CWA. This may cause confusion.
    In order to resolve this misunderstanding, you could ask your doctor's office or the laboratory responsible whether the technical requirements for reporting the CWA are met.
  3. An incorrect form was used to request a test. Currently there are still old forms in circulation which do not allow the completely digital process with the Corona-Warn-App. From mid-August onwards, only the new forms may be used. Further information can be found at https://www.kbv.de/media/sp/Ansichtsexemplar_Muster10C.pdf
    Also copied or photographed QR Codes lead to error messages. This sometimes happens when the medical practice or test centers do not have enough forms in stock.

Date: 10.09.2020

Why my test result in the Corona-Warn-App is not suitable for a "health report”

The information about the Corona-Warn-App does not replace the diagnostic letter or the information from the doctor or laboratory. In order to be able to present a letter for your employer, you need the personalized, written findings from the laboratory or test center. Due to the decentralized, data-saving approach chosen at the CWA, the app does not contain any personal data. Consequently, the test notification in the app is not sufficient for a health report.

Date: 10.09.2020

Questions about the Public health service / Laboratory

How to connect the laboratories to the app

The basic idea is that laboratories should also be able to send a positive test result for SARS-CoV-2 directly to the respective users in order to inform them more quickly, and thus reduce the risk of further spread of the pathogen.

This connection of the laboratories has two aspects: Firstly, the laboratories must be technically connected to the infrastructure of the Corona-Warn-App so that the results can be transmitted in the App. There is a corresponding registration hotline for laboratories for this purpose. The connection of the laboratories to the Corona-Warn-App is voluntary. Secondly, QR codes are required, which users can use to register their test in the App. These QR codes are part of a form of the Kassenärztliche Bundesvereinigung (KBV).

The existing reporting channels in accordance with the Infection Protection Act in the case of a positive test result remain unaffected by the automatic transmission.

Date: 29.09.2020

What information does the user of the app receive that he or she can pass on to the public health authority?

The following specific information is associated with the exposure notification "Increased Risk":

  • Number of exposures
  • Time since the last exposure (in days)
  • Number of days with exposure logging (max. 14 days)
  • Time of the last retrieval of positive identifiers (day/time)

Only the users themselves see this information in the app. A transfer to the public health authority is voluntary.

Date: 10.09.2020

How can the public health authority verify that the caller/visitor has an "increased risk" on his app?

The callers are asked to describe the exposure notification in the app in order to check the plausibility of receiving the notification. Furthermore, there is currently no way for health authorities to confirm beyond doubt that the caller has received an "increased risk" notification via the app.

If a user contacts the public health authorities, it is recommended to clarify the contact situation in a conversation - analogous to the usual procedure. For this purpose the details of the exposure notification from the app can be used, such as the number of exposures and the time since the last exposure. If possible, this is used as a basis for categorization as a Category I or II contact and appropriate measures are taken.

If the information is not sufficient for categorization, the following procedure is recommended:

  • Offer PCR testing for SARS-CoV-2
  • Indicate that a negative test does not rule out infection
  • emphatically point out AHA rules AHA-Regeln [in German only]
  • Make a recommendation to stay at home and reduce contacts if possible.
  • In special cases, the public health authority can order a separation at home or a ban on activities.

Date: 10.09.2020

Should every person with increased risk get a test for SARS-CoV-2?

No. The employees of the health authorities are required to clarify the contact situation in a conversation - analogous to the usual procedure - and on this basis to categorize the contact as a Category I or II contact and to order appropriate measures. However, the public health authority can also offer PCR testing if the information is not sufficient for categorization.

Date: 10.09.2020

Technical questions

How and where technical problems can be reported

Please contact our Corona-Warn-App hotline directly with any technical questions. This is available for you throughout Germany under the toll-free number +49 (0)800 7540001 from Monday to Saturday 7 a.m. to 10 p.m. The service staff there will help you immediately. Many thanks!

Further information and answers to frequently asked questions can also be found in the FAQ on our website at https://www.coronawarn.app/en/.

Date: 10.09.2020

How the Corona-Warn-App is being developed

The Corona-Warn-App will continue to be further developed after its release, so that it can provide even more targeted support in interrupting chains of infection. Improving the technical measurement parameters is one of the key issues - how precisely does the app record relevant encounter? Another factor is, for example, information on symptoms: If it is clear whether or from when a corona-positive person showed symptoms of COVID-19, the risk of infection can be better determined and other users can be notified more precisely.

In order to scientifically investigate the benefits of the Corona-Warn-App and other measures, an accompanying evaluation is required. The findings from this evaluation of the App will also be needed for future events and the development of technical solutions for other existing health problems. The RKI is mainly responsible for the scientific evaluation of the App and the assessment of the benefit. In order to enable a scientific discourse, other scientific institutions should also be involved. The possibility of evaluation will only be available in one of the following development stages of the App. Users will then have the opportunity to voluntarily participate in the scientific evaluation of the app and the related research questions on the COVID-19 situation in Germany.

Date: 10.09.2020

How many people have already been informed about a possible exposure?

All user data is encrypted and stored exclusively on the users’ smartphones. Neither the Robert Koch Institute as publisher nor third parties have access to these data. There is no information on how many people were informed about a possible exposure with the help of the Corona-Warn-App.

If a person who uses the App tests positive for the corona virus, he/she can voluntarily inform other users about it. The random codes of the infected person are then made available to all those who use the Corona-Warn-App.

Once you have installed the app, it will check if you have met the Corona-positive tested person. This check only takes place on your smartphone. If the check is positive, the app will show you - and only you - a risk notification ("increased risk").

Date: 29.09.2020

How the latest version of the Corona-Warn-App simplifies background updating on Android devices

The Corona-Warn-App worked at any time. Certain Android devices prevent apps from running permanently in the background. This does not only apply to the Corona-Warn-App, but to all apps on these smartphones. The device manufacturers have set this to save battery power. But even without this background update, the app exchanges anonymous codes with other smartphones that are nearby. The app also compares all stored anonymous codes with the server - but not automatically in the background for the affected devices, but when the app is opened. To enable automatic background updates, however, this problem could be solved by changing settings in the device.

The problem was already fixed with version 1.1.1. After the update the Corona-Warn-App should be opened briefly. In the settings (tap on the three dots in the upper right corner of the app, then tap on settings) you will find the item "Prioritized background activity". This function can now be activated with a slider. This removes the restrictions described above by the hardware manufacturer for the Corona-Warn-App.

We recommend opening the Corona-Warn-App once a day and checking the risk status.

Date: 10.09.2020

Why not all smartphones can install and activate the app

Currently the app can be installed on the following operating systems:

  • Android: From Android 6 with Google Play Service in a version from 20.18: The Exposure Notification API necessary for the app has already been installed here via the Google Play Services.
  • iOS: From iOS 13.5: The app runs on iOS smartphones from iPhone 6s. The version of the operating system must be iOS 13.5 or higher, since this version introduced the Exposure Notification API

People with smartphones that do not have these technical requirements are excluded from using the app, although they would be willing to use it occasionally. This is annoying but unfortunately unavoidable, since the so-called Exposure Notification API, a function that enables the identification of risk contacts (among other things by evaluating the duration of contacts) was only implemented by Apple and Google on these operating systems.

Date: 10.09.2020

Why do I get the message "exposure logging not possible?”

This problem is due to individual energy saving modes or battery settings of different manufacturers. These do not fully comply with the Android specification and often use too aggressive energy saving. The Corona-Warn-App is affected by these energy saving settings and therefore often cannot update the risk status in the background for a long time. However, there is a workaround:

  1. Open device settings
  2. Select 'Apps' or 'Apps & Notifications’
  3. Select 'Corona-Warn'
  4. Select 'Battery consumption'
  5. Select 'App Start'
  6. Disable 'Manage automatically'
  7. Activate 'Auto-Start‘
  8. Activate 'Secondary Start'
  9. Activate 'Run in background‘
  10. Restart the smartphone
  11. Start the Corona-Warn-App

These problems can also occur in other applications. Other manufacturers have therefore already provided a great deal of information on the solution, including device-specific information. Further information can be found e.g. at Slack. If our generic tips do not help, please try to apply the tips from the slack documentation for the Corona-Warn-App and the corresponding smartphone.

We are working on an extension of the Android app so that this setting can be done directly in the app and you don't have to go through the device settings anymore.

Date: 10.09.2020

How to disable “Send usage and diagnostics data” to Google

The Corona-Warn-App works with a very data-saving approach. However, smartphones with a Google operating system may automatically share telemetry data (e.g. on the frequency of App use) with Google through the Exposure Notification Framework developed by Apple/Google, on which the Corona-Warn-App is based. This data does not include health data. At the same time, the transmission of this data is not necessary for the unrestricted function of the Corona-Warn-App.

The automatic transmission of this data can be deactivated as follows:

  1. open the settings on the device
  2. tap Google >Three-Point Menu >Use and Diagnostics
  3. disable usage and diagnostics.

Details can be found here.

Date: 14.09.2020

Date: 18.01.2021