This is the current case definition

On this page

  1. Confirmed case
    1. Probable case
    2. Suspect case
  2. Rationale for current case definitions
  3. Close contact definition
    Casual contact definition
  4. Areas for increased testing and surveillance
  5. Notes
  6. Version control

Confirmed case

A person who tests positive to a validated specific SARS-CoV-2 nucleic acid test or has the virus identified by electron microscopy or viral culture, at a reference laboratory.

Probable case

A person, who has not been tested, with fever (≥38°C) 1 or history of fever (e.g. night sweats, chills) or acute respiratory infection (e.g. cough, shortness of breath, sore throat) and who is a household contact of a confirmed case of COVID-19.

Suspect case (current testing advice)

A person who meets the following epidemiological and clinical criteria:

Epidemiological criteria

Clinical criteria

Action

NSW specific testing

In NSW, testing criteria has been expanded to include individual patients:

  • who live in communities with local transmission, see:
    Areas for increased testing and surveillance
  • who self-identify as Aboriginal and have fever or respiratory symptoms
  • who have been referred by their GP or public health unit to a COVID-19 clinic for testing
  • whose clinician, after taking a full history, has reason to suspect that the patient may have COVID-19.

Fever (≥38°C) 1 or history of fever or acute respiratory infection (e.g. cough, shortness of breath, sore throat)

Test

Very high risk

  • Close contact (see Contact definition) in the 14 days prior to illness onset with a confirmed case
  • International travel in the 14 days prior to illness onset
  • Cruise ship passengers and crew who have travelled in the 14 days prior to illness onset

Fever (≥38°C) 1 or history of fever or acute respiratory infection (e.g. cough, shortness of breath, sore throat)

Test 2

High risk setting

  1. Two or more, plausibly-linked, cases of illness clinically consistent with COVID-19 (see clinical criteria) in the following settings:
    • Aged care and other residential care facilities
    • Military - group residential and other closed settings, such as Navy ships or living in accommodation
    • Boarding school
    • Correctional facilities
    • Detention centres
    • Aboriginal and Torres Strait Islander rural and remote communities, in consultation with the local PHU (see NSW specific testing)
    • Settings where COVID-19 outbreaks have occurred, in consultation with the local PHU
  2. People who, in the 14 days prior to illness onset lived in or travelled through a geographically localised area with elevated risk of community transmission, as defined by public health authorities 4 (see NSW specific testing)

Fever (≥38°C) or history of fever (e.g. night sweats, chills) or acute respiratory infection (e.g. cough, shortness of breath, sore throat) 3

Test (on site for aged care residents, where feasible)

Moderate risk

Healthcare workers, aged or residential care workers

Fever (≥38°C) 1 or history of fever (e.g. night sweats, chills) or acute respiratory infection (e.g. cough, shortness of breath, sore throat)

Test

Background risk

No epidemiological risk factors

Hospitalised patients with fever (≥38°C) 1 and acute respiratory symptoms (e.g. cough, shortness of breath, sore throat) 5 of an unknown cause

Test

  1. It is recommended that temperature is measured using a tympanic, oral or other thermometer proven to consistently and accurately represent core body temperature.
  2. Testing household contacts of confirmed cases of COVID-19 may not be indicated where resources are constrained. These cases would be considered ‘probable cases’ (see definition above).
  3. In certain high risk outbreak settings, public health units may consider testing asymptomatic contacts to inform management of the outbreak.
  4. For further information see geographically localised areas with elevated risk of community transmission​.
  5. Clinical judgement should be exercised in testing hospitalised patients. All patients should attend an emergency department if clinical deterioration occurs.

Rationale for current case definitions

The case definitions are based on what is currently known about the clinical and epidemiological profile of cases of COVID-19 presenting to date both in Australia and internationally. Health authorities are constantly monitoring the spectrum of clinical symptoms as cases arise, and, if there are any significant shifts, they will be reflected in the above definitions in future versions of this document.

The 14 day period is based upon what is currently known to be the upper time limit of the incubation period. As more precise information about the incubation period emerges, this will be reviewed.

Close contact definition

A close contact is defined as requiring face-to-face contact in any setting with a confirmed or probable case, for greater than 15 minutes cumulative over the course of a week, in the period extending from 48 hours before onset of symptoms in the confirmed or probable case, or sharing of a closed space with a confirmed case for a prolonged period (e.g. more than 2 hours) in the period extending from 48 hours before onset of symptoms in the confirmed case.

For the purposes of surveillance, a close contact includes a person meeting any of the following criteria:

  • Living in the same household or household-like setting (e.g. in a boarding school or hostel).
  • Direct contact with the body fluids or laboratory specimens of a case without recommended PPE or failure of PPE.
  • A person who spent 2 hours or longer in the same room (such as a GP or ED waiting room).
  • A person in the same hospital room when an aerosol generating procedure is undertaken on the case, without recommended PPE.
  • Aircraft passengers who were seated in the same row as the case, or in the two rows in front or two rows behind a confirmed COVID-19 case. Contact tracing of people who may have had close contact on long bus or train trips should also be attempted where possible, using similar seating/proximity criteria.
  • For aircraft crew exposed to a confirmed or probable case, a case-by-case risk assessment should be conducted by the airline to identify which crew member(s) should be managed as close contacts. This should consider:
    • Proximity of crew to confirmed or probable case
    • Duration of exposure to confirmed or probable case
    • Size of the compartment in which the crew member and confirmed or probable case interacted
    • Precautions taken, including PPE worn, when in close proximity to the confirmed or probable case
    If a crew member is the COVID-19case, contact tracing efforts should concentrate on passengers seated in the area where the crew member was working during the flight and all of the other members of the crew.
  • Close contacts on cruise ships can be difficult to identify, and a case-by-case risk assessment should be conducted to identify which passengers and crew should be managed as close contacts. (see Special Situations section of the COVID-19 CDNA national guidelines for public health units for further information).

Contact needs to have occurred within the period extending 48 hours before onset of symptoms in the case until the case is classified as no longer infectious by the treating team (usually 24 hours after the resolution of symptoms).

Casual contact definition

Casual contact is defined as any person having less than 15 minutes face-to-face contact with a symptomatic confirmed case in any setting, or sharing a closed space with a symptomatic confirmed case for less than 2 hours. This will include healthcare workers, other patients, or visitors who were in the same closed healthcare space as a case, but for shorter periods than those required for a close contact. Other closed settings might include schools or offices.

Note that healthcare workers and other contacts who have taken recommended infection control precautions, including the use of full PPE, while caring for a symptomatic confirmed COVID-19 case are not considered to be close contacts. However, these people should be advised to self-monitor and if they develop symptoms consistent with COVID-19 infection they should isolate themselves and notify their public health unit or staff health unit so they can be tested and managed as a suspected COVID-19 case.

Other casual contacts may include:

  • extended family groups, e.g. in an Aboriginal community.
  • aircraft passengers who were not seated nearby a symptomatic confirmed case or a crewmember who did not work in the same cabin area as a symptomatic confirmed case (see close contact definition).
  • passengers and crew on-board the same cruise ship as a symptomatic confirmed case (or cases), who are not considered to be close contacts. See Special situations for further information.

Where resources permit, more active contact tracing may be extended to other persons who have had casual contact (as defined above), particularly in school, office, or other closed settings. In these circumstances, the size of the room/space and degree of separation of the case from others should be considered in identifying contacts.

Areas for increased testing and surveillance

As of 12 April 2020 these areas have been identified for increased testing and surveillance.

Notes

These case and contact definitions are drawn from the COVID-19 CDNA national guidelines for public health units.

Where resources permit, more active contact tracing may be extended to other persons who have had casual contact (as defined above), particularly in school, office, or other closed settings. In these circumstances, the size of the room/space and degree of separation of the case from others should be considered in identifying contacts

Version control

Version 1.16

Version Major changes Implementation date
1.0 Removal of definition for fever 25 January 2020
1.1 Addition of “Fever or” to clinical criteria of suspected case. Addition of definition to the “Contact” setting. 4 February 2020
1.2 Addition of casual contact to epidemiological criteria. Addition of casual contact definition. 8 February 2020
1.3 Addition of ‘person under investigation’ and ‘Rationale for current case definitions’ sections. Replacement of references to ‘2019-nCoV’ with ‘COVID-19’ 16 February 2020
1.4 Inclusion of statement reflecting that passengers of the Diamond Princess cruise meet the criteria for close contact 18 February 2020
1.5 Addition of “validated” specific SARS-CoV-2 “nucleic acid” test in confirmed case. Addition that persons under investigation should be managed as a suspect case ‘Until COVID-19 is confirmed or excluded as the cause of illness’ 21 February 2020
1.6 Inclusion of South Korea and Iran in the list of countries in the ‘Person under investigation’ section 24 February 2020
1.7 Inclusion of Italy in the list of countries in the Person Under Investigation section. 26 February 2020
1.8 Inclusion of Cambodia in the list of countries in the Person Under Investigation section. 27 February 2020
1.9 Inclusion of country transmission risk assessment 2 March 2020
1.10 Inclusion of B and C in ‘Suspect case’ definition 7 March 2020
1.11 Revised case definition revision 10 March 2020
1.12 Revised case definition to remove casual contacts and new advice for health care workers 13 March 2020
1.13 Revised case definition 24 March 2020
1.14 Revised close contact definition for airline crew 24 March 2020
1.15 Inclusion of NSW ​​specific testing criteria 31 March 2020
1.16 Revised case definition 7 April 2020
1.17 Revised contact management – close contact definition 18 April 2020
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Current as at: Saturday 18 April 2020
Contact page owner: Health Protection NSW