Scary number of virus cases undetected


Tens of thousands of coronavirus cases may have gone undetected in Australia, according to a federal government-funded study.

Researchers from the Australian National University have developed a new test that can detect previous COVID-19 infection in a patient's blood.

The ANU study suggests for every 3000 healthy Australians, eight had likely been unknowingly infected with the virus. No one in the study had previously returned a positive test.

Academics said the new "highly sensitive test" measured the antibodies that followed previous infection with SARS-CoV-2 - better known as COVID-19.

The study was conducted just before Melbourne's second wave of outbreaks.

"Our best estimate is around 0.28 per cent of Australians (one in 350) had been infected with SARS-CoV-2 by that time," Associate Professor Ian Cockburn said.

Thousands of COVID cases may have gone undetected. Picture: NCA Newswire / Gaye Gerard
Thousands of COVID cases may have gone undetected. Picture: NCA Newswire / Gaye Gerard

"This suggests that instead of 11,000 cases we know about from nasal swab testing, about 70,000 people had been exposed overall."

Dr Cockburn explained that when a person is infected with COVID-19, the immune system produces antibodies. The test measures those antibodies to determine if someone has previously been exposed.

Researchers said the test would help authorities gain a better grasp of the spread of the illness - and could help demonstrate whether or not herd immunity exists.

The John Curtin School of Medical Research director Professor Graham Mann added that the test would be useful to monitor the spread within the community, particularly among people who may be asymptomatic.

"It is another weapon in our armoury to combat further waves of the virus," he said.

There have been close to 27,000 positive cases in Australia since the pandemic began, the majority of those were diagnosed during Victoria's second wave.

Originally published as Scary number of virus cases undetected