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A dispute has arisen among scientists over a new report on the use of face masks by the general public as an approach to managing the spread of Covid-19 in the community.
The report by a multidisciplinary group convened by the Royal Society called Delve – Data Assessment and Learning for Viral Epidemics – has weighed the evidence and has come out in favor of the public wearing face masks, including homemade cloth covers, in an attempt to Board Covid -19.
“Our analysis suggests that its use could reduce forward transmission by asymptomatic and pre-symptomatic users if it is widely used in situations where physical distance is not possible or predictable, in contrast to the standard use of masks for the protection of users, “notes the report. “If used correctly on this basis, face masks, including homemade cloth masks, can help reduce viral transmission.”
The guidance of the World Health Organization (WHO) on facial masks has remained constant during the coronavirus pandemic. It has stuck to the line that masks are for healthcare workers, not the public.
“Wearing a medical mask is one of the preventive measures that can limit the spread of certain viral respiratory diseases, including Covid-19. However, the use of a mask alone is not sufficient to provide an adequate level of protection, and other measures must also be taken, “said the WHO.
However, as some countries have eased closing conditions, they have made it mandatory to use face covers outside as a way to try to ban the spread of the virus. This is in the belief that covering the face will prevent coughing and sneezing from expelling the virus from a great distance.
There is no strong scientific evidence, in the form of trials, that common masks prevent the virus from infecting people who use it. There is also concern that the public does not understand how to wear a mask correctly, and can become infected if they come in contact with the virus when they remove it and then touch their faces.
Underlying WHO concerns are the shortage of high-quality protective masks for front-line healthcare workers.
However, masks play a role when worn by people who are already infected. It is accepted that they can block transmission to other people. Since many people with Covid-19 show no symptoms in the first few days after becoming infected, the masks clearly have a potential role to play if everyone uses them.
Sarah Boseley Health editor
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The conclusion is based on an analysis of three key considerations, including the role of droplets as a transmission path, and whether masks can help reduce droplet dispersion. However, the authors note that there are only a small number of studies.
But the report led other scientists to express their reservations, warning that it amounted to nothing more than an opinion and exaggerated the available evidence.
Dr. Simon Clarke, an associate professor of cellular microbiology at the University of Reading, said the report “provides no new evidence and casually rules out the precautionary principle in addressing the possibility that masks and covers may have negative effects on behavior. of people”.
He added: “Until further evidence is presented in either direction, all advice can be based on opinion.”
Dr. Ben Killingley, consultant in acute medicine and infectious diseases at University College London hospital, was also critical.
“The report is overly optimistic about the value of facial coatings and it is incorrect to conclude that the evidence shows that facial coating can reduce viral transmission in the community,” he said. “In fact, there is no good evidence that facial covers achieve this.”
Killingley added that the report largely ignored real-world data, suggesting low effectiveness, albeit for user protection.
“This is not to say that facial coatings may not be helpful,” he said, noting that mask studies have not been conducted during a pandemic or in the context of a new virus. “However, the report, in my opinion, does not accurately represent the evidence on facial covers that currently exists,” he said.
Dr. Antonio Lazzarino, from the Department of Epidemiology and Public Health at University College London, agreed.
“That is not a piece or an investigation. That’s an unsystematic review of anecdotal and non-clinical studies, “he said.
“The evidence we need before implementing public interventions involving billions of people should ideally come from randomized controlled trials at the population level or at least from observational follow-up studies with comparison groups,” Lazzarino said, noting that it will allow Experts note the Pros and Cons of wearing masks.
“Based on what we now know about Covid-19 transmission dynamics and pathophysiology, the negative effects of wearing masks outweigh the positive ones,” he said.
But Professor Trisha Greenhalgh, of the Nuffield Department of Primary Care Health Sciences at Oxford University, welcomed the report, saying it adds weight to the argument that the general public could be part of a route to shutdown. closing.
“It gathers a large body of evidence including the science of transmission and efficacy of fabric-based materials in both laboratory studies and randomized controlled trials, regarding source control and user protection.” said.
“The authors point to the important finding that, if not most, Sars-CoV-2 transmission [coronavirus] It happens from people who currently have no symptoms. As would be expected from this distinguished group of scientists, the underlying evidence base is meticulously dissected and presented, including pointing out areas where more research is needed. ”
Greenhalgh noted that while there have been concerns that the use of masks by the public could reduce the supply of medical-grade masks for health workers, a homemade mask is sufficient for most people. “There is no need for medical grade masks outside of healthcare settings. A cloth mask offers very good protection and is more comfortable to wear, “he said.
