How contact tracing works

Information on contact tracing, locations of interest, and how the NZ COVID Tracer app works.

What contact tracing is

If someone has COVID-19, the Ministry of Health and district health boards (DHBs) find people who may have had exposure to the virus. This process is contact tracing.

More about contact tracing — Ministry of Health website (external link)

If you are a contact of someone with COVID-19

A contact is someone who has had exposure to a confirmed or probable case of COVID-19. You are a contact if you were at a location of interest at the same time as a person with COVID-19.

There are 2 types of contacts:

If you are identified as a contact and use the NZ COVID Tracer app, you may get a notification that will provide advice and more information. The Ministry of Health or your Public Health Unit may also contact you.

Locations of interest

Locations of interest are places where someone confirmed with COVID-19 visited.

Depending on the circumstances, you are considered a contact if you were at a location of interest at the same time. There are different levels of contact — the Ministry of Health lists locations of interest and has advice on what you need to do if you are a contact.

Locations of interest in New Zealand | (external link)

How contact tracing works using the NZ COVID Tracer app

The NZ COVID Tracer app is our fastest way of responding to the virus — the faster we respond, the faster we stop it. The app also keeps people informed of the risk.

1. There is a community case of COVID-19

Usually this is from a COVID-19 test, someone visiting a doctor when ill or calling Healthline.

2. Contact tracing interviews

The person with COVID-19 is interviewed along with the people they live and work with. They will be asked if they have used the official NZ COVID Tracer app to scan QR codes.

If they have, this gives us all the information needed to:

  • start finding the source of a cluster or community transmission
  • find anyone else who has had exposure to the virus.

It helps if they have also taken notes for those times when the QR code was not available.

If they have not used the app, there is a much more lengthy process to find out the same answers. This slows things down considerably, allowing COVID-19 more time to spread to others in the community.

3. An alert may be sent from the app

If the person was using the app and scanning QR codes, we can be certain of where they were at exact times. An alert can be sent via the app, warning others of the risk.

The different alerts

If you have scanned in somewhere that someone with COVID-19 has been at the same time, you will see a yellow alert on the app dashboard.

If you have Bluetooth tracing turned on, and it identifies you have been close to someone with COVID-19, you will see an orange alert on the dashboard.

Find out more about the different NZ COVID Tracer alerts you can get | (external link)

4. People who get an alert should follow health advice

If an alert does go out, anyone who has been using the app will get information telling them they may have had exposure to COVID-19. This will include information on what you should do next to protect yourself, your whānau and the community.

People who do not have the app will not be able to receive the alerts. That means there may be a delay before they find out if there is a threat of the virus in their community.

How you can help make contact tracing easier

You can help make contact tracing easier for health officials by continuing to keep a record of where you go and who you meet.

Scan QR codes or keep a record of where you have been

If you own or run a business:



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