Case definition of COVID-19 infection

The Ministry has developed this case definition for COVID-19 based on expert advice from our Technical Advisory Group.

Case definition update – 27 February 2020

The Ministry of Health’s Technical Advisory Group (TAG) has this morning revised the case definition for COVID-19. The TAG has updated its advice to include two categories for countries or areas of concern. The key difference being people who travel to New Zealand from or via those countries listed in category one in the last 14 days should self isolate for 14 days and contact Healthline.

Anyone who has travelled from or via all countries listed in both categories with clinically compatible symptoms should be considered a suspect of COVID-19 case and testing performed.

Countries or areas of concern (as at 27 February 2020)

Category one: Mainland China

People who have travelled from or via from countries in category one in the last 14 days are required to self-isolate for 14 days and contact Healthline after they have left the countries listed. 

Category two: Hong Kong, Iran, Italy, Japan, Republic of Korea, Singapore and Thailand

People who have travelled from or via countries lists in category two who develop symptoms of fever, cough or shortness of breath should seek medical advice by first phoning Healthline’s dedicated COVID-19 number 0800 358 5453 or contacting their GP including phoning ahead of their visit.

Case definition (as at 27 February 2020)

Epidemiological criteria

Travel to or from (excluding airport transit) countries or areas of concern (see below) within 14 days before onset of illness

OR

Close contact[1] with a confirmed case of SARS-CoV-2 infection in 14 days before onset of illness in any country.

Clinical criteria

Fever or history of fever (≥38°C) and acute respiratory infection with at least one of the following symptoms: shortness of breath, cough or sore throat.

Laboratory criteria

Laboratory definitive evidence requires at least one of the following:

  • Detection of SARS-CoV-2 from a clinical specimen by NAAT (PCR) and confirmed by NAAT on a second specific genomic target
  • Detection of coronavirus from a clinical specimen using pan-coronavirus NAAT (PCR) and confirmation as SARS-CoV-2 by sequencing
  • [Significant rise in IgG antibody level to SARS-CoV-2 between paired sera when serological testing becomes available]

Laboratory suggestive evidence requires:

  • Detection of coronavirus from a clinical specimen using pan-coronavirus NAAT (PCR)

Note: If all laboratory tests are negative, other respiratory pathogens should be excluded.

Case classification

  • Under investigation: A case that has been notified, but information is not yet available to classify it as suspect, probable or confirmed.
  • Suspect: The patient is classified as a suspect case, pending further investigation, if they satisfy both the clinical and epidemiological criteria.
  • Probable: A case that meets both clinical and epidemiological criteria where other known aetiologies that fully explain the clinical presentation have been excluded, and either has laboratory suggestive evidence or for whom testing for SARS-CoV-2 is inconclusive.
  • Confirmed: A case that has laboratory definitive evidence
  • Not a case: A case that has been investigated and subsequently found not to meet either the probable or confirmed case definition.

Countries or areas of concern (as at 27 February 2020)

Any one with clinically compatible symptoms from the countries and/or areas listed below (Category 1 and 2) should be considered a suspect COVID-19 case and testing performed.

Category 1

  • Mainland China

Category 2

  • Hong Kong
  • Iran
  • Italy
  • Japan
  • Republic of Korea
  • Singapore
  • Thailand

Notes

  • Travelers from Category 1 countries should self-isolate for 14 days after they have left the Category 1 country and register with Healthline. They should also be advised of COVID-19 symptoms and to call the Healthline number if they become unwell.

[1] ‘Close contact’ is defined as:

Any person with the following exposure to the case during the case’s infectious period, without appropriate personal protective equipment (PPE):

  • Direct contact with the case, their body fluids or their laboratory specimens
  • Presence in the same room in a health care setting when an aerosol-generating procedure is undertaken on the case
  • Living in the same household or household-like setting (e.g. shared section of in a hostel)
  • Having spent two hours or longer in the same room (such as a general practice or ED waiting room) or in another closed space (including a train compartment or a bus)
  • Having been seated within 2 rows either side of a case on a flight
  • Having been face-to-face (within one metre of the case) for more than 15 minutes in any setting 
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