Coronavirus contagion: What a positive test for Covid-19 really means

Apr 17, 2020
Many people are wondering how long you're infectious after contracting Covid-19. Source: Getty.

You test positive for coronavirus, self-isolate until you return a negative test result, then you’re free to resume normal activities – or as normal as the current environment allows. That’s the scenario many Aussies picture when it comes to the Covid-19 diagnostic process.

But that’s not how the process actually pans out in Australia currently, and there are still some unknowns as to when the virus stops being contagious, with scientists and doctors working overtime to understand how Covid-19 remains in the body and what that means for your own state of health as well as that of people around you.

So we’ve looked into the current guidelines for people diagnosed with coronavirus and talked to experts about what those guidelines mean.

Official guidelines for coronavirus contagion

According to the federal Department of Health, if a person infected with coronavirus has been symptom-free for three days and it’s been more than 10 days since their first symptoms, they are no longer considered infectious. This stance was developed in consultation with the Communicable Diseases Network of Australia and has not been updated since April 6.

Each state and territory, however, has a slightly different interpretation of the guidelines because, as the federal department notes, each region is at a difference stage in the spread of the virus and thus local chief health officers must decide on what’s appropriate for their region. As such, some regions have stricter post-Covid-19 testing requirements before you’re free to end self-isolation.


You can return to normal activities if you’ve had no symptoms for the previous 72 hours and it has been at least 10 days since the start of your symptoms. There are additional requirements for healthcare and aged care workers, however, including a requirement for negative pathology testing.

South Australia

You can end self-isolation if it’s been at least 10 days since you first had symptoms and you’ve been symptom-free for 72 hours. If you were admitted to hospital for COVID-19 or you work in healthcare or aged care, extra requirements may apply.

New South Wales

If you have a mild case of coronavirus, you can end self-isolation if at least 10 days have passed since the onset of your symptoms and all symptoms of your acute illness have been resolved for the previous 72 hours.

Western Australia

If you test positive for coronavirus, you are to remain in self-isolation until you recover and are cleared by the state’s health department to resume your normal activities.


If you have been diagnosed with coronavirus, you may need to have further specimens collected, such as nose and throat swabs, to determine that you are no longer infectious. A Public Health Officer will advise you of these requirements and when your isolation has finished.

Northern Territory

If your test is positive, you will need to stay in isolation until you recover and are cleared by a Public Health Officer before returning to normal activities.

Australian Capital Territory

If you haven’t been hospitalised, you can be released from isolation if at least 10 days have passed since the onset of first symptoms and at least 72 hours have passed since the resolution of all acute symptoms.


If you have a positive result, you must stay in isolation until you recover and are cleared by a Public Health Officer before returning to normal activities.

Does this mean you’re no longer infectious?

The government guidelines are based on the most recent understanding of the virus but Mary-Louise McLaws, an expert in infection diseases who is a member of the World Health Organization’s coronavirus advisory panel and a professor of epidemiology at the University of New South Wales, told Starts at 60 that it’s still somewhat of a guessing game as to how Covid-19 infections occur.

Because it’s a very new virus, there are many things that are unknown and one unknown is how likely is it for someone who had the virus, been isolated and been symptoms-free for three days, to go on to cause infections in others,” Prof McLaws says. 

Recent research suggests that the virus can still be detected in your body, even if you have fully recovered. A study from Hong Kong found the virus could be detected for 20 days or longer after the initial onset of symptoms in a third of patients tested. Another study from China found the virus in a patients’ faecal samples five weeks after the first onset of symptoms.

Read more: What it’s really like to have Covid-19: Two Aussies share their experience

Indeed, a positive test for coronavirus doesn’t necessarily mean you’re infectious because it’s possible to have a ‘false-positive’ test result, Prof McLaws adds.

“False-positive results may occur in someone who’s no longer infected but the swab test picks up the skeleton of the virus, that is not active and can’t cause infection. That’s a limitation of this test,” she explains. “The authorities understand the problem of false-positive results and [that] cases who have been under isolation without symptoms for three days may not pose a threat to the community spread and [so] allow them to leave isolation while applying the usual social distancing.”

Even a negative test result isn’t currently a certainty the virus has passed, with South Korea this week reporting that 91 people who had had coronavirus and then received negative test results subsequently testing positive for the virus again.

Should I wait for a negative Covid-19 test result?

The short answer is no. Unless you’re a healthcare worker or work in an aged care facility, you don’t require a negative test for coronavirus to released from home isolation. However, as a precaution, you must still continue to practise social distancing and good hygiene.

IMPORTANT LEGAL INFO This article is of a general nature and FYI only, because it doesn’t take into account your personal health requirements or existing medical conditions. That means it’s not personalised health advice and shouldn’t be relied upon as if it is. Before making a health-related decision, you should work out if the info is appropriate for your situation and get professional medical advice.

Have you been directly affected by coronavirus?

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