What contact tracing is
If someone has COVID-19, the Ministry of Health and district health boards (DHBs) track down people who may have been exposed to the virus. This process is called contact tracing.
Types of close and casual contacts
There are several types of ‘contacts’:
- close plus contacts
- close contacts
- casual plus contacts, and
- casual contacts.
The Ministry of Health gives advice to all these types of contacts on what they need to do.
Close or close plus contacts
Close contacts or close plus contacts are those who are likely to be at a higher risk of being infected.
If you have been identified as a close contact or close plus contact of someone with COVID-19, the Ministry of Health or your Public Health Unit will contact you.
Casual plus contacts
Casual plus contacts are people who have had exposure to a case, but who do not meet the criteria of a close contact. For casual plus contacts, their contact was where there is higher risk for transmission.
In some specific higher-risk situations, the Ministry of Health may contact you if you are a casual plus contact.
Casual contacts are people who have had exposure to a case, but who do not meet the criteria of a close contact or a casual plus contact.
Locations of interest
Locations of interest are places where someone confirmed with COVID-19 visited.
If you visited a location of interest at a certain time, depending on the circumstances you may be classed as a contact. 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.
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. COVID-19 is detected in the community
Usually this is from a test, someone visiting a doctor when ill or calling Healthline.
2. The person with COVID-19, and people living and working with them, are interviewed
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 quickly start pinpointing the source of a cluster/community transmission and anyone else who may have been exposed to the virus. It also helps if they have also taken notes for those times when the QR code wasn’t available.
- If they have not, there's 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 issued on 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 issued via the app, warning others of the risk.
- If they were not using the app, an alert probably will not be able to be sent — to avoid sending false alerts and worrying people needlessly.
4. Others who receive the alert self-assess and decide whether to contact Healthline
- If an alert does go out, anyone who has been using the app instantly receives information telling them they may have been exposed to COVID-19. They then self-assess whether they or anyone they know has symptoms, and get in touch with Healthline if they do.
- 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.