South Australian Premier Steven Marshall
South Australian Premier Steven Marshall (Image: AAP/David Mariuz)

South Australian premier Steven Marshall said yesterday the strain of COVID-19 in Adelaide was “particularly sneaky”.

“[It’s a] highly contagious strain … and if we don’t get on top of that very, very quickly it will get away from us and that will be disastrous,” he said.

Earlier this week, SA chief public health officer Nicola Spurrier said the virus had a “very, very short incubation period”, infecting people in 24 hours or less.

“The other characteristic of the cases we’ve seen so far is they have had minimal symptoms and sometimes no symptoms but have been able to pass it on to other people,” she said.

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But what Spurrier is describing is typical of every strain of COVID-19. There is no evidence to suggest Adelaide’s strain is worse than any other.

What are they talking about?

Adelaide’s COVID-19 strain came from a returned traveller from the UK, then spread to a hotel quarantine cleaner and her family. Twenty-three people have since been infected.

But there’s no evidence to show the UK strain is worse than any other, says Professor Nigel McMillan, director of infectious diseases and immunology at Menzies Health Institute Queensland.

“The fact people are becoming infected quickly isn’t unusual … 40% of people who have the virus don’t show signs of it,” he said.

The virus likely spread quickly because the cleaner had a high viral load — meaning she was shedding more virus particles. This has nothing to do with the strain, and is likely dependent on a person’s immune response, McMillan said.

“There’s nothing unusual from reports I’m seeing about this virus.”

Where’s the evidence?

University of Queensland virology associate professor Ian Mackay told Crikey every version of the virus was a mutant version.

“One person would have a mutated version of COVID-19 to the person sitting next to them,” he said. The differences are so minute, Mackay prefers to call them variants instead of strains.

What matters is whether these mutations have an effect on how the virus behaves. So far, just one strain, D614G, has mutated to a point where it’s a little more effective at spreading. This strain has been circulating in Australia for months.

To be sure, scientists will need to see the virus’ genome sequence. But the SA strain has yet to be uploaded to any databases.

“Once they get that they’ll be able to match it up with other variants around the world and see what else it might be doing,” he said.

Sequencing usually takes a minimum of two days. 

Is this an appropriate tactic?

Exaggerating the virus’ danger may be effective at getting people to take precautions, but could be unnecessary, UNSW Sydney ageing and mental health senior research fellow Dr Adrienne Withall told Crikey.

“[Officials are] trying to show people how serious the threat is, especially when we’re reaching a time when fatigue over COVID-19 messaging may have set in,” she said.

At the same time, the government shouldn’t cause undue alarm and hysteria.

“I think the fact we saw toilet paper shortages once again in SA shows that people are still vulnerable to a sense of panic when emotive language is used.”