The number of active coronavirus cases in Australia could be 10 times higher than the official figure, new analysis suggests – but the chief medical officer disagrees

There could be 20,000 active coronavirus cases in Australia, far more than official numbers suggest. (Photo by James D. Morgan, Getty Images)
  • There are only around 3,000 active coronavirus cases in Australia, according to official reports.
  • But new modelling by the Actuaries Institute, the representative body for the actuarial profession in Australia, shows that number could actually be far closer to 20,000, ten times the official figure.
  • Douglas Isles, the actuary behind the analysis, has warned Australians to not get complacent and urged more testing to be made available to get a more accurate picture of community infections.
  • Visit Business Insider Australia’s homepage for more stories.

While Australia has been one of the most successful countries in the fight against COVID-19, the official numbers could be understating the extent of the outbreak.

Official figures on Thursday show there have been around 6,447 confirmed cases with 63 deaths. While not disputing the veracity of those figures, the Actuaries Institute has completed modelling which suggests the total of active cases – those who currently have the virus – could be far higher than the roughly 3,000 recognised officially.

“Australia has done a lot of tests compared to other countries, around 370,000 in total, but that’s still just 1% of the total population,” Douglas Isles, the actuary behind the analysis, told Business Insider Australia. “But we know there are a far higher number of active cases or carriers of the virus than the confirmed figures that are being reported.”

By taking hard data from sources like the health department and the World Health Organisation (WHO), Isles said he worked backwards with a “reasonable set of assumptions” to estimate how many people historically have had the virus and how many would still have it today.

On 9 April, Isles, who estimates there would have been around 20,000 cases, or nearly 10 times the reported number.

“We’ve tested 1% of the population and 2% of that group has this virus. If we haven’t tested the other 99%, it’s unlikely that there are zero people with the virus in that group. Even if the 99% have a much smaller infection rate, there will still probably be a much larger number of infected people who have not yet been tested.”

Addressing the media last week, Australia’s chief medical officer Brendan Murphy hinted at such a problem, acknowledging the number of undiagnosed cases as a major concern.

“More than 500 people have acquired the virus from someone in the community who doesn’t know they’ve had it,” Murphy said on April 7. “That is why we cannot relax what we are doing.”

However, when the study’s figures were put to him at a media conference on Thursday, Murphy said he thought the actual figure “is unlikely” to be so high although maintained the government “can’t be absolutely sure”.

“[We have] a range of general practices which test every single person with respiratory illness, we are testing every unusual pneumonia in every hospital, [so] if we had that level of undetected cases we would have found out by now,” he said.

While Murphy might digress from Isles’ reasoning, the two share the same concern about the virus and the threat levity poses to its containment.

Isles was inspired to complete his modelling after he witnessed the number of people who crowded Bondi Beach on that infamous Friday in March. Suspecting the same complacency would once again creep into the Australian consciousness in the coming weeks, he began trying to quantify the real presence of COVID-19 in Australia.

“It just doesn’t make sense to me that we’re right now so intently focused on a sample size of 1% when its infection numbers are just a fraction of what the likely total is,” Isles said, noting his main concern is that underreporting will lead to a common misunderstanding of the virus.

“The average person I suspect looks at the numbers being reported and thinks we have this all under control and not that many people have it. I think people should be informed if nothing else and cognisant of the absolute level of this in the community,” he said.

While acknowledging the early success of Australia’s containment efforts, Isles believes we could do more in the way of testing.

“I would say we should be doing more random testing in the same way we do for alcohol and drugs to get a more accurate sample size,” he said.

“Absent a vaccine, we’re going to have to learn how to live with the virus. Inevitably we are going to relax restrictions one day and policymakers will need to have a clear picture of how many infections are actually in the community to decide when and how to do that.”

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