The latest evidence shows that getting reinfected with COVID-19 can occur within a short period of time. Reinfection will become more likely as new variants spread among the community
Last updated: 21 September 2022
If you have had COVID-19 before and get new symptoms
If you develop new symptoms consistent with COVID-19, and it’s 29 days or more since a previous infection, it’s possible you have a reinfection with COVID-19 and you should test using a rapid antigen test (RAT).
For most people illness caused by reinfection is likely to be no more severe than a previous infection, but they can experience different symptoms.
If you are reinfected with COVID-19 you will have access to the same advice, help and support as you would receive for a new COVID-19 infection.
28 days or less since your last infection
If COVID-19 symptoms return and it is 28 days or less since your last COVID-19 infection:
- there is no need to take a RAT
- you should stay home and recover until 24 hours after you no longer have symptoms.
Some people recovering from COVID-19 may have symptoms that come and go for some time afterwards or they may be caused by other infections like the common cold, flu or a chest infection.
If you have an underlying health condition or your symptoms are getting worse, seek advice from a health practitioner or call Healthline on 0800 358 5453.
29 days or more since your last infection
If you test positive:
- this will be considered a reinfection and you should follow the standard COVID-19 isolation guidelines.
If you test negative:
- your symptoms could be another infection, such as the flu or another virus
- if your symptoms continue you should repeat a RAT 48 hours later
- if your result is still negative, then stay at home until at least 24 hours after your symptoms resolve.
If you have an underlying health condition or symptoms that are getting worse, you should call Healthline on 0800 358 5453 or your local healthcare provider.
Reinfection with COVID-19 – what we know so far
Reinfection refers to the detection of a second or subsequent COVID-19 infection, regardless of the variant involved.
You are more likely to become reinfected as your immune response from the vaccine, or your previous COVID-19 infection, decreases over time.
It is still unclear how common reinfections are but they’re likely to become more common as new variants and subvariants spread across New Zealand.
We are constantly monitoring international and national data and updating our reinfection guidance as new evidence becomes available.
Changing from 90 days to 29 days or more
Early in the COVID-19 pandemic, many countries chose to advise not to test within a 90-day period of an initial infection, when reinfection was thought to be unlikely and difficult to diagnose with PCR.
Evidence now shows that reinfection can occur within 90 days, particularly with new variants.
In recognition of this evidence our advice is now to test from day 29, if you experience new COVID-19 symptoms following a previous infection.
Within 29 days of a previous infection it is very difficult to diagnose reinfection because symptoms, viral levels and test positivity can continue to vary for some weeks following an infection with COVID-19.
Evidence on reinfections is evolving rapidly. We will continue to monitor emerging information on reinfection and update this advice as new evidence becomes available.
Read more: COVID-19 infection and immunity
Monitoring reinfection in the community
When someone uploads a positive RAT into My Covid Record, if it is 29 days or more since their last infection, they will be categorised as a reinfection and given the same advice and support as for a new infection.
Using this data from My Covid Record we can now monitor the number of people with a reinfection with COVID-19. Information on the number of reinfections will be included in COVID-19 updates published on our website.
Guidance for clinicians
We have updated our clinical guidance for healthcare providers about how to manage patients who present with symptoms consistent with COVID-19, or a positive COVID-19 RAT, after a previous COVID-19 infection. This advice is now included in the COVID-19 Testing Guidance.