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About the app

What is the purpose of this app?

Smitte|stop is an app designed to help Danish public health authorities contain the spread of COVID-19 as society slowly reopens. COVID-19 can be transmitted through close proximity to affected individuals. Right now, we have a limited number of people infected with the coronavirus in Denmark. We want to keep it that way even though people have started meeting at workplaces, in public transportation and have begun socialising.

By using the app, you can easily and anonymously let people with whom you have had close contact know that you have been diagnosed with COVID-19. This includes people you meet randomly, e.g. people you meet in public transportation, at theatres, in cafés etc.

Thus, the app is an essential part of transitioning back to daily life while managing the risk of further outbreaks.

How does the app prevent coronavirus transmission?

​Traditional methods of contact tracing are critical to containing the spread of the coronavirus. Technology can support and augment these efforts by allowing the public health authorities to quickly notify people who may have been exposed to a person who has contracted COVID-19, including those the person might not know directly. This is exactly what the Danish health authorities wish to accomplish with the smitte|stop app.

When you are in close proximity to another individual who has the smitte|stop app on his or her smartphone, the smartphones will start sending signals (IDs) to each other by using Bluetooth-based contact tracing. In this way, your phone registers other people’s phones with which you have had close contact.

If an app user is diagnosed with COVID-19, the app will remember that you, i.e. your phone, has had close contact with that person. You will then receive a notification warning you that you might have been exposed to the coronavirus. In the same notification, Danish health authorities will advise you on how to react to the exposure and how you can help limit further spread of COVID-19.

And vice versa. You can use the app to let those app users with whom you have had close contact know if you have been diagnosed with COVID-19. Then they can follow the recommendations given by the Danish health authorities as well as prevent further coronavirus transmission.

Rest assured, there is no information to tell you who those people actually are or where you were when you were near them. Your identity is not shared with other users either. In the notifications, you are completely anonymous. No one will know the identity of the one who has been diagnosed with COVID-19 and subsequently has shared that information in the app.

How do I start using the app?

The app is currently only available in Danish. However, if you have basic Danish skills you should be able to install and use it, or you could ask someone you know for help.

To start using the app, you should follow these steps:

  1. Go to App Store or Google Play Store and download smitte|stop. You have to install the latest version of the operating system on your phone to do that.
  2. When you use the app for the first time, you are required to consent before the app can save data on your phone about your recent close contacts.
  3. You are also required to consent before the app can use the technology called “The Exposure Notification System” developed by Google and Apple.
  4. The app will now register your recent close contacts. The app works even though your screen is turned off.

This app is just one initiative amongst many in the fight against the transmission of COVID-19. We therefore kindly ask that you follow the recommendations provided by the Danish health authorities about social distancing and hygiene even though you use the app.

How does “Exposure Notification System”- technology works?

Once you opt-in to the notification system, the Exposure Notifications System will generate a random ID for your device. To help ensure these random IDs can’t be used to identify you or your location, they change every 10-20 minutes.

Your phone and the phones around you will work in the background to exchange these privacy-preserving random IDs via Bluetooth. You do not need to have the app open for this process to take place.

Your phone periodically checks all the random IDs associated with positive COVID-19 cases against its own list. If there is a match, the app will notify you with further instructions and recommendations from the Danish health authorities on how to keep you and the people around you safe.

How do I let other users know that I have been diagnosed with COVID-19?

You can use the app to anonymously let those other users that you have been near know that you have been diagnosed with COVID-19.

Follow these steps:

  1. On the start screen of the app, you press where it says “Er du testet positiv?” (Have you tested positive for the coronavirus?).
  2. Then you have to use your NemID-login to confirm your positive test. Your positive test will be confirmed by linking you to the Danish database that contains information about all COVID-19 positives. This is a means of preventing fake positives.
  3. We will now ask you if you have had any symptoms of COVID-19 and when your symptoms started. The app uses this information to calculate which app users you have been in close proximity to.
  4. Finally, the app will ask you, if you want to share the IDs that your phone has released the previous 2 weeks (14 days to be exact). If you agree to share your IDs, all of your recent close contacts will receive a notification warning them that they might have been exposed to the coronavirus. In the same notification, they will receive recommendations and instructions from the Danish health authorities on how to react to the potential exposure and what they can do to limit further spread of COVID-19.

Will I be notified if I have been in close contact with someone who has COVID-19?

Once you have successfully installed the smitte|stop app and consented, you will get a notification from the app if you have been in close contact with another smitte|stop user who is subsequently diagnosed with COVID-19. In the notification, you will receive recommendations and instructions from the Danish health authorities on how to react to the potential exposure and what you can do to limit further spread of COVID-19.

The recommendations are:

  • staying at home and cancelling all visits
  • being especially diligent in complying with the Danish Health Authority's general advice on proper hand hygiene and cough etiquette, focusing of cleaning, limiting physical contact, maintaining social distancing and showing careful consideration to people at higher risk of severe illness from COVID-19
  • paying particular attention to whether they develop symptoms of COVID-19
  • getting in touch with their GP or the unit for contact tracing in the The Danish Patient Safety Authority on 32 32 05 11 as soon as possible, even if they have no symptoms so they can be referred for testing.

Can I use the app in foreign countries?

If you are on vacation or works in a foreign country and you are in close proximit to other users of the Danish version of the smitte|stop app, the app will register your contact. However, the app cannot register users diagnosed with COVID-19 from other countries’ public health authorities.


If you have any questions or problems with the app, you can contact sundhed.dk’s support.

Write an email to info@sundhed.dk or call 44 22 20 80.

The phone is open:

  • Monday – Thursday: 9.00 - 15.00
  • Friday: 9.30 - 15.00

The support is closed Saturday, Sunday and national holidays.