The number of newly reported COVID-19 cases is skyrocketing in Australia's most populous states, but epidemiologists say the real number of new infections in the community could be up to 10 times higher.
“The numbers are going up and we’re letting [them] go up because [Omicron is] not really as serious as Delta,” University of Melbourne epidemiologist Professor Tony Blakely told SBS News.
“But the numbers we’re seeing are just the tip of the iceberg. We don’t know what the true infection rate is but we [can guess].”
Speaking to The Age earlier this week about the outbreak in Victoria, Kirby Institute epidemiologist John Kaldor said it would not be too wild to suggest there were at least three to five times as many cases as officially notified.
“I would say, it’s five to 10 times, so let’s use five, that means we’re seeing something like 160,000 to 180,000 infections per day at the moment in New South Wales," Professor Blakely said.
These evaluations, however, are not yet based on any modelling.
“There are population surveys that ask people about their symptoms, about their testing behaviours and testing outcomes. So if you can put that information together in a systematic way, it’s possible to generate an estimate,” Professor Kaldor told SBS News.
“Active attempts [are being made] at the moment to try to improve this estimate and we may have some clarity on this in coming days and weeks.”
In the absence of those estimates, Professor Blakely said, there are three major reasons to believe the real number of infections is much greater than the reported cases.
“One [reason] is asymptomatic infection. We knew with Delta that a third of people were probably asymptomatic. It might be even two-thirds with Omicron [so] they don’t even know they’ve got it,” he said.
Melbourne University epidemiologist Professor Tony Blakely. Source: Supplied
“Two, we’ve got long testing queues and so many people will just shrug their shoulders with mild symptoms and get on with their lives.
“Three, those people who’ve found out they test positive [through] a rapid antigen test don’t register on accounts.”
After Wednesday's National Cabinet meeting, Prime Minister Scott Morrison announced a spate of changes to COVID-19 guidelines. One change means people who test positive on a rapid antigen test won't be required to take a PCR test.
While Professor Blakely's projections may sound alarming, he noted the number of hospitalisations as a result of those infections is much lower than would have been the case if Delta was still the dominant COVID-19 strain.
“And the other good news is that 180,000 [people being] infected per day [is] not going to last too long because you’re going to run out of people to infect, " he said.
“As each day passes by, there’s going to be a lower and lower percentage of the population left, who are susceptible and able to catch the virus.
“At the same time we’re boosting people, so I’m expecting that this [situation] in New South Wales will peak quite soon - in the next week or so.”
NSW recorded 34,994 infections of COVID-19 and six deaths on Thursday, while Victoria posted 21,997 cases and six deaths and Queensland reported 10,332 new cases and one death.
