The Victoria State Government has used “low-grade” mask studies to justify the mandate, experts say | Victoria

Studies that the Victoria State Government has relied on to justify its strict masking obligations have been criticized by some doctors and epidemiologists as evidence of “low grade.”

Experts emphasized that it is important to wear a mask indoors and that the mask helps reduce transmission, “World’s first” joint research It was flawed by Burnet’s Lab and Kirby’s Lab.

the study, Published in the medical journal Plos One In July, we used newspaper photos and surveys to assess the impact of masks on compliance and Covid rates.

NS Victorian Maskman Date It is controversial because it is necessary to wear a mask at all times, especially in open spaces outdoors, despite strong evidence that the risk of indoor infections, especially in the home, is significantly higher.

In August, Prime Minister Daniel Andrews also said Victorian people Forbidden to remove the mask to drink alcohol It can be removed outdoors, however, for eating and drinking non-alcoholic beverages. The Plos One investigation was used by the government to justify its policy. This policy applies even if people are walking outside with no one nearby.

The study analyzed images of people in public places from a digital archive of The Age newspaper taken between July 10 and August 2, 2020.

From these, three periods from July 10th to 19th (the period before the announcement of the mandatory mask policy), using all the photos taken in public places in Melbourne’s urban areas, such as cityscapes and shopping centers. We calculated the percentage of people wearing masks in public places across. July 20-22 (the period from the announcement of mandatory mask wear to the start). From July 23rd to August 2nd (required mask wearing period). The researchers also conducted a survey.

The paper found that “compulsory mask use policy was associated with a significant increase in public use of masks and a significant decrease in new COVID-19 cases.”

According to a Burnet’s Lab press release, a “world’s first” survey found wearing a mask “Almost overnight” turned the pandemic around And it was the only and most important tool to change the flow of Victoria’s second Covid wave in 2020.

“Given the increasing evidence of outdoor infections of delta mutants, it makes sense for masks to be worn both indoors and outdoors during the outbreak of Covid-19,” the authors of the study said. Said in a press release to promote.

However, the study has been questioned after published concerns about the methodology of the dissertation. According to a report on, the Department of Health in Victoria pointed out the study as evidence to support its mission.

Researcher Kyle Sheldrick, who first expressed concern about the paper, said the study had many methodological problems.

“It’s amazing to draw a picture from a picture taken by a news photographer from a particular publication as the basis for causal inference,” Sheldrick said. “News photographers don’t go out, they just take random samples of people in the community. They’re in charge of photography for specific stories and editorials. It’s hard to think of more biased samples.”

Sheldrick said there was a discrepancy between the method described and the results reported, And publicly detailed his concerns..

“Although the newspaper archivist has shown that he has checked these two 14-day unpublished photos, to be honest, few additions have been made and all the images in the results have been analyzed. , The results of that search are never explained. The results only explain 44 published images, “he said.

Infectious disease doctor Professor Peter Corignon agreed with Sheldrick, saying: Observational studies were one of the weakest types of studies.. This is because it is often impossible to prove the cause and effect. Also, there are too many “confounding factors” that are difficult to control but can affect results.

“I think it was a mistake to use this study for any policy,” Corignon said.

“I don’t think this is a high level of evidence because there are so many potential flaws in the methodology. If you need high-quality evidence, Randomized, controlled, double-blind study.. Well, this study is not, and any evidence would consider the standard to be low grade. “

Gideon Meerowitz Katz, an epidemiologist at the University of Wollongong, said the study was “not robust enough to determine the causal link between masking obligations, masking, and reduction of Covid cases.”

“The authors used two methods to derive estimates of changes in masking behavior, but neither clearly indicated the number of people wearing masks in a city or state over time. “He said. “The photo is a media shot and is not representative of the population. The survey was conducted only for a short period of time and included only 18 people since July 23.”

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However, a randomized controlled trial in Bangladesh found that mask policies could have a reasonable impact of around 10% on cases, he said. “Therefore, it is important to note that a flaw in one study does not mean that the mask does not work,” he said.

The Burnet’s Lab, which provides modeling to the Victoria State Government, described Sheldrick as a “doctoral student” in a statement and said he supported the study.

“We accept that not everyone needs to agree to our work … others, including the reviewers of our dissertation, had different ideas,” the statement said. I did.

“Our paper … showed that the introduction of a compulsory mask policy in Melbourne was consistent with a significant reduction in cases. The introduction of the policy was with other restrictions that allowed its own assessment of its potential. Was introduced separately. This is unusual and is the reason we claimed to be the “world’s first” at the time. “

Sheldrick said he was disappointed with the lab’s response.

“This answer is two because it does not address specific criticisms such as the fact that all” before “photos were taken late in the afternoon and all” after “photos were taken before lunch. There is really no way to make a meaningful comparison, “he says. Said.

Professor Catherine Bennett, director of epidemiology at Deakin University, said the study was a useful contribution. She put on the mask, admitting that the researchers looked at the photos and data from the “very small window” and assumed a linear relationship between the mask and the reduced Covid case, which is “a little unusual in the epidemic curve.” Shown. The policy was translated into the public adopting the measure.

“Tracking it and ensuring that policies lead to changes in community practices is a beneficial contribution,” she said.

The Victoria State Government has used “low-grade” mask studies to justify the mandate, experts say | Victoria

Source link The Victoria State Government has used “low-grade” mask studies to justify the mandate, experts say | Victoria

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