"world first" Australian face--mask study labelled as "crap"

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A “world-first” Australian study which Victoria’s government has held up as proof its mandatory face mask policy worked is riddled with basic errors and should never have been published in a major journal, medical researchers and experts say.

Victoria first made face masks mandatory outside the home in Melbourne during its second coronavirus wave in July 2020, but the Department of Health and Human Services has been unable to provide any scientific research or studies upon which the decision was made.

Instead, DHHS directed news.com.au to a paper published in July this year by the Burnet Institute – an influential public health body which has come under fire in recent months for its alarmist predictions – as justification for the mandate which has resulted in thousands of dollars in fines for Victorians.

The study claimed the mandatory face mask rule had turned the pandemic “almost overnight”.

“There has been a lot of low-quality research that has come out in the pandemic, but for this to be used as a basis for a policy change is staggering,” said Dr Kyle Sheldrick, a medical researcher and PhD candidate at the University of NSW.

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Dr Sheldrick said despite its obvious flaws, very few scientists would be willing to publicly call out the study.

“Not just in relation to this paper but in general I think there has been a reluctance to criticise research and to criticise public health interventions [during the pandemic] and to be seen as a wrecker,” he said.

“Unfortunately there is a culture in science which sees criticising other researchers or research as something fundamentally bad – that we should be presenting a united front to laypeople.”

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‘The data set is useless’

The Burnet Institute study relied on images from the photo library of The Age newspaper showing Melbourne community settings to conclude that mask usage rose from 43 per cent to 97 per cent after the July 22 mandate came into effect.

Dr Sheldrick said it was “hard to think of a worse methodology to answer this question than just looking at which photos are collected by a metropolitan newspaper”.

“Even ignoring the fact that the photos were taken for an editorial purpose, that this is not a random sample, when you look at the actual data in the Excel spreadsheet it is stunning to me,” he said.

The spreadsheet lists the date, time and location of 44 photos – 19 taken before the announcement, 18 after mask rule came into effect and seven in between. Nearly all of the photos in the before group were taken between 2pm and 4pm, while nearly all of the photos in the after group were taken between 8am and 12pm.

“Which just means the data set is useless,” Dr Sheldrick said.

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Commenters on Plos One have highlighted other errors, including the authors’ claim that there was “no reason to believe that mask usage changed in the healthcare setting during the study period”.

Safer Care Victoria’s chief medical officer Professor Andrew Wilson told the RACGP’s newsGP in October last year that the state’s guidance had been updated on August 1.

“In response to emerging evidence, the Victorian guidance was upgraded on August 1 to use Tier 3 PPE [including N95 respirators] in caring for patients with known or suspected Covid-19 infection who are cohorted in wards, intensive care units and emergency departments,” he said.

Paper admits ‘causality’ difficult

More broadly, Dr Sheldrick said it was odd that the paper singled out the mask mandate as the key reason for the fall in transmission out of all of Victoria’s sweeping lockdown measures, which included retail closures, movement restrictions and an 8pm curfew.

The paper’s authors even conceded that Covid-19 transmission fell at the same time in rural areas, where masks were not introduced.

“Care should be taken in ascribing causality,” they wrote.

“We cannot determine whether masks had a direct effect or whether near-universal adoption of masks reminded wearers to engage in other behaviours recommended to reduce SARS-CoV-2 transmission, including regular hand hygiene and physical distancing. Interestingly, introduction of masks in Melbourne coincided with a decrease in the growth rate in rural areas, where masks were not introduced, which is consistent with an indirect effect, a decrease in seeding of rural areas from the Melbourne, or both.”

Dr Sheldrick said it “certainly seems like” the authors were working backwards from a conclusion.