Coronavirus Australia: Experts warn herd immunity is a myth

It’s a term thrown around a lot by people campaigning for lockdowns to be lifted – but “herd immunity” is actually a myth, experts say.

A leading health expert has warned of the severe consequences if Australia aimed for herd immunity.

Professor Raina MacIntyre, an infectious diseases expert, said if the country lifted lockdown there could be continued epidemics of coronavirus, more absenteeism and increased deaths.

Herd immunity is the idea that exposing the population to the virus builds up natural immunity. About 60 per cent of the population, or 15 million people, would need to be infected for such a strategy to work.

But Prof MacIntyre, of the University of NSW’s Kirby Institute, said the concept of herd immunity was a myth.

“What you will see is a large increase in cases for little gain because probably by the time you get to about 20 to 30 per cent of the population impacted, you'll start putting the brakes on and having more lockdowns because the health system will be too severely impacted,” she said at a COVID-19 pandemic update at the institute.

“We'll have these cycling epidemics, large proportions of absenteeism from work and see the full spectrum of disease – as has been seen in the US, the UK, Europe and China – which is that you are seeing deaths in children, infants and young people.

RELATED: Restrictions could be lifted in three weeks

Herd immunity would mean millions of Australians would need to be infected with coronavirus. Picture: Brendan Read

“You'll start to see healthcare workers dying as they are dying in those countries … that will impact your capacity to treat other conditions. If half your workforce is off sick or in quarantine because you’re having a massive outbreak in your hospital, you may not be able to get treatment if you turn up with your myocardial infarction.”

Australia isn’t pursing herd immunity, instead opting for containment or elimination.

The idea of allowing people to get infected deliberately has been described as “offensive” and akin to murder.

Associate Professor Adam Kamradt-Scott, at the University of Sydney's Centre for International Security Studies, also said herd immunity wasn’t a good option.

“At the moment we don't know how long the length of immunity for SARS-CoV-2 will be,” he said.

“We also don’t know whether there might be very minor mutations that would see a slightly different strain start to circulate. If that was to occur, we don’t know yet whether previous exposure would provide sufficient immunity.”

“We are making a lot of educated guesses at the moment based on previous pandemics but the fact is we haven't faced something like this in more than 100 years.”