It's the phone call no one wants to receive right now. "Hello, I'm calling from the Department of Health. You recently underwent a test for COVID-19..."

But these contact tracing calls, and the people making them, are among Australia's most effective weapons when in comes to combating the spread of the novel coronavirus. 

Dr Ben Scalley is the head of the COVID-19 contact tracing team at WA Health. He walked Mamamia through exactly what's involved in this life-saving, frontline work.

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Who are contact tracers?

Government contact tracing teams existed well before the COVID-19 pandemic. As now, their role has been to squash outbreaks of diseases that make their way into Australia, like measles, for example.

They do this by notifying positive cases of the disease and working quickly to identify who that person has been in close contact with so they too can be isolated and/or treated.

But as cases of COVID-19 began to swell in China at the beginning of the year, state governments began to prepare their contact tracing teams to operate on a far larger scale than ever before.

Western Australia's team, for example, swelled from the existing group of "a couple of doctors and around 10 nurses" to roughly 150 as the state battled its COVID-19 case peak in March and April. 

Should more be required, Dr Scalley said, personnel will be recruited from more diverse professional backgrounds in health, such as physiotherapists, occupational therapists and even retired health workers.

In New South Wales, the team is currently around 300 strong, while in Victoria, where cases have surged by thousands in recent weeks, it's reportedly closer to 2000. 

What happens when a contract tracer calls?

The first task of a contact tracer is to deliver the unfortunate news to the person who has tested positive.

"A lot of people that we call have some concern about their own health, but also they're extremely worried, often, about family and friends they've been in contact with. They start thinking about their elderly mother or grandparents," Dr Scalley said.

"What's come through really strongly from the start of this pandemic is that the element of mental health is as — if not more — important than many other aspects.

"So there's definitely this element of supporting people through their journey with COVID-19."

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The next crucial task is to ensure the person is isolating well.

"That means that they need to stay at home, or if they're in a quarantine hotel, of course, stay there," he said.

"It also means that they need to be separated from any other people, like their family members. So we talk about ensuring that they have their own room, their own bathroom and they're not sharing any parts of the house. And then once we've done that, we have a very, very detailed conversation about where they might have been while they were infectious and look at who they may have exposed."

Did they visit a restaurant? At what time? Who with? For how long were they there? Did they sit indoors or outdoors? Did they go to a workplace? What meetings did they have? Did they use the lunchroom? Who else uses that lunchroom?

It's not as simple as just asking them exactly where they've been, Dr Scalley said. It's typically multiple conversations over the course of several days, often adding up to about three to four hours.

Dr Scalley likens it to detective work. And like detectives, contact tracers lean on particular interview skills to get the information they need.

"There are ways to trigger people's memory," he said. "I remember talking to one person in the peak of the cases in W.A. and he was obviously very into AFL. I quickly searched what game was on that weekend, and I said, 'This was the day when the [Freemantle] Dockers were playing...' some other team. And in that way, he remembered exactly what he was doing."

Physical evidence can also be helpful. Credit card statements, for example, work diaries, calendars, emails, call history and more.

Finding close contacts.

The people the tracers are looking for are called 'close contacts'. 

Based on current understanding of how SARS-CoV-2 (the virus responsible for COVID-19 disease) spreads, that means anyone who has had face-to-face contact with a known case for 15 minutes or more.

"The other one is [people who've shared] a close, confined area, like a small to medium room, for a couple of hours," Dr Scalley said. "And normally the vast majority of people that get infected with COVID-19 have had exposure at that level."

These close contacts are tracked down by the tracers, informed of their isolation requirements and then contacted regularly over the course of two weeks before they can be cleared. 

In some instances, there may be dozens of close contacts. For example, last week in NSW, when there were 94 community transmitted cases, NSW Health contact tracers made calls to 4,985 people.

If you have any of these symptoms, however mild, get tested:
🔸Fever, chills or sweats
🔸Cough
🔸Sore throat
🔸Shortness of breath
🔸Runny nose
🔸Loss of sense of smell or taste
Staying apart, keeps us together. Find out where to get tested at https://t.co/mzfR6VpMSn pic.twitter.com/zHzEFnB8fM

— Victorian Government (@VicGovAu) August 2, 2020

At no point is the source of their possible exposure revealed to them.

"We work very hard to maintain the privacy of the person involved. So we don't routinely give out the names of cases," Dr Scalley said. "We very much try to limit any information that we share... Only what's necessary to manage the public health risk."

Some are expecting the call, but for others it comes a total shock.

"They're being called and told they have to stay home, potentially for the next two weeks, and not work and not have a social life. That's a really hard task," Dr Scalley said.

"But people listened and people did what was required, and that's a large reason why [Western Australia has] done so well so far."

(The state currently has just six active cases and has recorded 642 in total.)

How you can make a contact tracer's job easier.

Contact tracing can be at its most effective when members of the public do everything in their power to limit the possible spread of infection, Dr Scalley said. 

That means, for example, maintaining hand hygiene, coughing and sneezing into your elbow, not going to work or restaurants if you feel at all unwell, getting tested if you have cold-like symptoms and isolating yourself until you receive your results.

No one wants to recieve that call. But when it comes, you want to be the person who did everything to make the contact tracer's job easier.

It could save lives.

Featured image: AAP.