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.

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.

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.

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.

Evaluation of the Corona-Warn-App

The Robert Koch Institute is evaluating the effectiveness of the Corona-Warn-App. App users can participate in this evaluation on a voluntary basis. This evaluation with user participation includes the following:

  1. the Event-Driven User Survey (EDUS) among users of the Corona-Warn-App. Users can take part in a survey after they have received a red warning.
  2. Privacy Preserving Analytics. Users are asked to voluntarily donate their data to analyse app usage while their privacy remains protected.

The privacy of the users who participate in the evaluation is preserved at all times. More detailed information can be found in the following overview: Evaluation of the Corona-Warn-App: How user privacy remains protected (PDF, 167 KB, File does not meet accessibility standards.)

The evaluation is accompanied by numerous scientific associations and universities. The results will be used to further develop the Corona-Warn-App, for example by improving the algorithms for risk calculation and optimising the user guidance in the app. Moreover, it allows for an evaluation of the Corona-Warn-App’s use.

More details on the evaluation can be found here.

Overview of new and upcoming functionalities

With version 2.0, the German contact tracing app, Corona-Warn-App, has been upgraded to include the option of event registration for indoor cluster detection.

Users can register their participation in an event by scanning a QR code created by the organiser in the Corona-Warn-App. No personal data is collected in the process. The events in which the user participated (or whose QR code was scanned) are stored in the app’s contact diary on the smartphone. If the user later receives a risk notification (warning), s/he can identify whether the risk encounter took place in connection with one of the registered events.

You can read more details in the development team’s blog: https://www.coronawarn.app/en/blog/

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 (28.4.2021)

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 automatically receives a warning on the screen.

You can read more details here: https://github.com/corona-warn-app/cwa-documentation/blob/master/cwa-risk-assessment.md

Date: 28.04.2021

How the risk calculation has changed with the switch to the more advanced Apple/Google interface

The Corona-Warn-App is based on the so-called Exposure Notification Framework (ENF) from Apple and Google. With version 1.9 of the Corona-Warn-App, it was converted to the further developed interface (version 2 of the Exposure Notification Framework, ENF).

Specifically, the following aspects have changed: In the case of several encounters with increased risk (red), users are now shown the date on which the last encounter with increased risk took place.

In addition, the epidemiological risk assessment has changed: Now, several - individually considered - encounters with low risk (green) can lead to an increased risk (red): Depending on the infectivity, 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 taken place, but no longer the number of encounters.

With the change to ENF 2.0, a single encounter is no longer decisive for the risk assessment, but the sum of the risk minutes per day. Thus, even several risk encounters of short duration can lead to an increased risk.

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

Date: 28.04.2021

What the contact diary is all about

The Corona-Warn-App has a contact diary. With this function, users can document in an integrated calendar who they have met and when they have met the person. The use of the function is voluntary. If a user does not want to use the function, this has no effect on other functions of the Corona-Warn-App.

The contact diary is accessed via the start screen of the app under the button "Keep diary". Subsequently, users have the option to enter who they have met ("Add person") and where they have been by date ("Add place"). This information is stored for a period of 16 days and only on the smartphone itself. If the user tests positive for SARS-CoV-2 within this period, the contact diary serves as a reminder to inform people with whom there has been contact in the previous days.

Date: 28.04.2021

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

The incubation period is the time from infection to the onset of the disease. On average, it is 5 to 6 days (range 1 to 14 days).
The serial interval defines the average interval from the onset of illness of an infectious case to the onset of illness of a case infected by this case. The Robert Koch Institute estimates the median serial interval for SARS-CoV-2 at four days, which is supported by various studies. Moreover, a considerable proportion probably become infected 1 to 2 days before the onset of symptoms of the infected person. Therefore, to cover all eventualities in the app, the range of 14 days was used.

Date: 28.04.2021

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

Questions about the test result (28.4.2021)

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

Being tested positive for SARS-CoV-2 - What the user should do in the Corona- Warn- App

If a positive test result is automatically transmitted via the Corona-Warn-App, the user is asked to share this information with other users in order to warn them if necessary.

Specifically, this works when the person who tested positive uploads its own random codes (day codes) to the Corona-Warn-App server. All active Corona-Warn-App regularly download the random codes published on the Corona-Warn-App server and transfer them collectively to the operating system via an interface. The smartphones of the other users are checked for random codes received and recorded that match a random code of the person tested positive for SARS-CoV-2.

If there is a match, the risk of transmission is determined in a multi-stage procedure and - if defined threshold values have been exceeded - the user is informed of the possible risk assessment (low or increased risk) by means of a message. The other users do not find out who the person, tested positive, is with whom they had a risk encounter.

In addition to informing the tested persons via the Corona-Warn-App, the family doctor naturally gets a notice of the findings. In parallel, the processes regarding the legal reporting obligations are running, so that the responsible public health department will also contact the person tested positive in a timely manner to discuss further measures.

The Robert Koch Institute strongly recommends and asks that persons who have been tested positive and are therefore infectious, isolate themselves in order to avoid further infections.

Date: 28.04.2021

How positive tests can be registered in the app

If the user agrees to an automatic result transmission via the Corona-Warn-App when taking the test, the test result will be displayed on the tested person's smartphone as soon as it is available. If the test result is positive, the tested person will be asked to share this information with the other users of the Corona-Warn-App.

If the automatic transmission of the test result is not possible or if the QR code 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.

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

Date: 28.04.2021

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

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

Questions about the Public health service / Laboratory (28.4.2021)

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

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: 28.04.2021

Technical questions (28.4.2021)

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 developed after its release so that it can provide even more targeted support in interrupting infection chains. The project partners (SAP, Deutsche Telekom) will provide regular information on the details of new functionalities.

As with many other digital applications, the development of the Corona-Warn-App does not end with its launch, but is a project that continues to be worked on to fix known bugs and make further improvements. The developers of the Corona-Warn-App continue to incorporate tips received through the various channels into the update process of the app. An overview of the various topics in development can be found here: https://github.com/corona-warn-app/.

Date: 28.04.2021

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

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

Questions regarding event registration (28.4.2021)

The benefits of event registration with the Corona-Warn-App

Using Bluetooth low-energy technology the Corona-Warn-App can determine a risk of infection if people have had contact at a distance of up to approx. 1.5 metres for a period of at least 10 minutes.
Based on what is currently known about the virus, however, aerosols spread over much greater distances in poorly ventilated indoor spaces. The risk of becoming infected indoors is therefore many times higher than in outdoor areas. To better reflect this increased risk, the Corona-Warn-App has been upgraded to include event registration. This way, people can also be warned who were in a room with a SARS-CoV 2 infected person at the same time.

Date: 28.04.2021

How event registration works with the Corona-Warn-App

Organisers can use the Corona-Warn-App to create a QR code for their events. A location in the sense of a concrete (street) address is not required. Guests can then check in for the event by scanning the QR code in their Corona-Warn-App. The check-in is stored locally on their smartphone.

If a guest later tests positive for SARS-CoV-2, she/he can share the check-in along with their own random codes via the app. Random codes and check-ins are downloaded regularly from all smartphones with an activated Corona-Warn-App. The matching process takes place decentrally on the smartphones of the other users. If there is a match - e.g. because one was a guest at the same event - one receives a red or green warning, depending on the duration of the joint stay on site.

This way, possible clusters can be recognised and chains of infection can be interrupted quickly on an event basis. Like all previous functions of the Corona-Warn-App, the event registration and subsequent warning in case of infection is based on the data-saving peer-to-peer principle, i.e. the users warn each other without a central instance.

Date: 28.04.2021

Which data is being collected for event registration

Like all other functions of the Corona-Warn-App, the event registration is also designed to be data-saving. All data is stored exclusively on the users’ smartphones. No personal contact details are registered, no location data is being transmitted.

If a person registers to attend an event by scanning the corresponding QR code, the information is stored locally in the app’s contact diary. The QR code describes an event with attributes, a street address is not required. The QR code is also a random ID that is not processed further in the app.

If a visitor later tests positive for SARS-CoV-2, he/she can share the check-in together with his/her own random codes via the app and thus upload it to the Corona-Warn-App’s server. The smartphones of all users regularly request random codes and check-ins from the server and compare them with the locally stored information. Other guests at the same event then receive a red or green warning, depending on the duration of the shared stay at the location.

Date: 28.04.2021

How the Corona-Warn-App’s event registration is different from apps like Darfichrein, Luca-App, etc.

The Corona-Warn-App facilitates a quick warning of its users after contact with an individual who tested positively. Through event registration, infection clusters can be better recorded and the individual risk assessment can be adjusted in the app.

Check-in apps such as Darfichrein or Luca, for example, are used to digitally record the contact details of participants at an event (digital contact tracing). In the event of infection, the Corona-positive person can hand over these contact details to the responsible public health authority.
The public health authority then contacts all persons who also participated in the event or scanned the QR code.

Date: 28.04.2021

How to prevent misuse of QR codes for event registration

The Corona-Warn-App relies on the sensible and responsible use of the functionalities. Misuse of the event registration - e.g. people checking in at events without actually being there - can therefore not be completely ruled out.

In order to keep the risk of misuse as low as possible, we call on all users to handle the check-ins responsibly. This includes, in particular, only making the QR codes for check-in available to participants at the event in question and not publishing them via digital media, for example. We also recommend that QR codes be renewed regularly, but at least once a day. Various technical measures have also been taken on the system side to reduce the risk of misuse.

Date: 28.04.2021

Date: 28.04.2021