Victoria’s coronavirus second wave has already peaked thanks to mask wearing, and horrific daily case spikes mask a lower ‘true’ infection rate, an epidemiologist claims.
Professor Tony Blakely from the University of Melbourne used a five-day average to smooth out daily numbers, providing a more accurate picture than the official government figures, he claimed in Pursuit.
Over the last week, Victoria has seen COVID-19 case numbers fall sharply only to rise again even higher, and grim secret government modelling reported on Wednesday predicted multiple days of more than 1,000 daily cases later this month.
But Prof. Blakely said his own work appeared to show the state’s curve began to turn on July 30, and hit back at the leaked modelling, which he claimed was inconsistent with Victoria’s actual numbers.
He said the wild variations in numbers are more than can be explained by chance and suggested there must be ‘batching’ happening to cause the spikes.
‘Batching refers to the fact that at one or more steps along the path, notifications or tests, are batch-processed,’ Prof. Blakely explained.
‘It may mean that a large batch of notification of contacts comes in as one “data drop”. Or a large batch of swabs are sent to the lab at the same time. And probably, most importantly, the batching of the laboratory test results when they go back to the Victorian Department of Health and Human Services (DHHS).’
Prof. Blakely produced a graph showing the five-day average figures as a smooth red line against a more jagged blue line of the official daily figures.
He also pointed out the last two figures for August 6 and 7 are estimates, as those official figures are yet to be included.
‘I have tried to be as useful as possible, whilst appropriately cautious. The impetus for these projections is to counter those in The Australian,’ he said.
A report in The Australian on Thursday showed a forecast for coronavirus numbers in Victoria of more than 1,000 daily cases in the next few weeks.
Prof. Blakely the source of the report was not disclosed and neither was the method and assumptions used in the predictions.
The figures were claimed to have been leaked from the government, but this was denied by the Victorian premier.
‘No one in the government has ever seen it,’ Daniel Andrews said on Thursday.
Prof. Blakely said with the official figures smoothed out using his calculations the worst looks to be over for Victorians growing increasingly frustrated with strict lockdowns.
‘It looks like the curve turned at 30 July. But more importantly, it makes sense.’ he said.
He explained July 30 is about a week from when mandatory mask wearing was put in place by the Victorian government – which is also slightly more than the virus’s five day incubation period.
‘Mask wearing appears to have bent the curve, consistent with expectation. Or put another way, the numbers would be higher now without mask wearing, and much higher again without Stage 3 restrictions.’
He predicted a significant drop in the smoothed-out daily numbers would occur about 10 days from when Victoria put Stage 4 restrictions in place on Thursday.
He said once the numbers drop to around 200 per day, which he expects Stage 4 restrictions will achieve, then contact tracing teams will be less overwhelmed and the state will be able to keep the numbers down.
‘Maybe then we can discuss whether elimination still remains an achievable goal, or whether all of us are going to have to learn to live with the virus circulating at some level until we (hopefully) get a vaccine,’ he said.