As of 27 March 2019 the National Guidelines for Public Health Units define probable and suspected cases of Coronavirus COVID-19 as:
A person with fever (≥38°C) 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 (see Contact definition below) of a confirmed or probable case of COVID-19, where testing has not been conducted.
A person who meets the following epidemiological and clinical criteria:
|Epidemiological criteria||Clinical criteria||Action|
|Very high risk Close contact* in the 14 days prior to illness onset with a confirmed or probable 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)||Test2|
|High risk setting Two or more cases of illness clinically consistent with COVID-19 (see clinical criteria) in the following settings: Aged care and other residential care facilities Military operational settings Boarding schools Correctional facilities Detention centres Aboriginal rural and remote communities, in consultation with the local PHU Settings where COVID-19 outbreaks have occurred, in consultation with the local PHU Individual patients with illness clinically consistent with COVID-19 (see clinical criteria) in a geographically localised area with elevated risk of community transmission, as defined by PHUs||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 (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)3 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 or probable cases of COVID-19 may not be indicated where resources are constrained. These cases would be considered ‘probable cases’ (see definition above)
3 Clinical judgement should be exercised in testing hospitalised patients. All patients should attend an emergency department if clinical deterioration occurs.
A close contact is defined as requiring:
- greater than 15 minutes face-to-face contact in any setting with a confirmed case in the period extending from 24 hours before onset of symptoms in the confirmed 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 24 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 school classroom; communal room in an aged care facility). See Special situations for further information specific to aged care facilities and schools.
- 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 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. See Special situations for further information.
- If an aircraft crew member is the COVID-19 case, 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 for further information.
Contact needs to have occurred within the period extending 24 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).
- 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.
- Contact tracing is not required for close contacts arriving on international flights on or after 16 March 2020.