The risks associated with COVID-19 have evolved greatly. It's time to reconsider the need for routine masking
During the early stage of the COVID-19 pandemic, when there were no vaccines or effective antiviral drugs, wearing a mask was thought to provide barrier protection against viral contact and thus infection. The virus and the risks associated with it have since greatly evolved. Is it now time to reconsider the need for routine masking?
For many, the wearing of masks was considered to be a politicized response that restricted an individual’s freedom of choice. The controversy was also fuelled by initial ambiguity over the benefits of masks, as masks were never recommended for previous viral outbreaks. They were also in short supply early in the COVID-19 pandemic and their use was limited to those in direct contact with infected people. Initial advice was thus that masks should be restricted to health-care workers and those who had been infected.
Masks are thought to provide barrier protection against the two primary methods of viral transmission, namely droplets and aerosols. Droplets are larger particles, about 1/3 the size of a human hair, and are expelled through sneezing or coughing or even breathing. Aerosols are a finer mist, with particles the size of about 1/100th of a human hair.
Do masks really work?
The medical use of masks started with the desire to prevent potentially infectious droplets from being secreted into an exposed wound by an operating surgeon.
Masks have been used to try to control infection as far back as the 1918 influenza pandemic, although those masks, which showed no apparent wide-scale benefit, were likely made of porous cloth. Currently available masks include blue surgical-grade masks and KN95 masks as well as tight-fitting N95 medical masks. Each provide progressively higher levels of barrier protection.
Cochrane Review
Their conclusion was that “Wearing masks in the community makes little or no difference to the outcome of influenza-like illnesses (such as COVID-19) compared to not wearing masks.” There was also no difference in benefits comparing the use of a surgical mask versus an N95 mask when used in routine settings including health care. Hand washing was found to be moderately effective in preventing infection.
The critique of the Cochrane Review was that it looked only at preventing the wearer of a mask from becoming infected, whereas it didn’t look at the benefit of an infected but asymptomatic wearer not spreading their germs to others. Previous observational studies have shown that masks worn by people infected with influenza reduced the risk of spread to others.
“It would be accurate to say that the review examined whether interventions to promote mask wearing help to slow the spread of respiratory viruses, and that the results were inconclusive. Given the limitations in the primary evidence, the review is not able to address the question of whether mask-wearing itself reduces people’s risk of contracting or spreading respiratory viruses,” Soares-Weiser stated.
In other words, the study found no conclusive evidence that wearing a mask in the community protects wearers who are not infected from respiratory infections. There is anecdotal evidence that wearing a mask indoors in crowded quarters with low-quality ventilation and many infected people may slow spread. This represents very few current situations.
Are masks safe?
Blue surgical masks are usually made of non-woven polypropylene fabric, a complex polymer plastic made from petroleum. While the polymer is relatively non-toxic the mask may sometimes have trace amounts of formaldehyde, a known carcinogen, and bronopol, both of which can be facial irritants causing contact dermatitis. The plastic is also used in many containers that can be heated safely. While thought to be safer than most other plastics used for containers, there are some reports of an effect on androgen hormones and a stress response in cells. I remain concerned that wearing a mask all day for years and breathing through a woven, complex plastic fibre may be a health hazard.
In addition, the billions of masks produced and worn are generally not bio-degradable and represent an increasing disposal problem.
What should current guidance be?
Health Canada and the Centers for Disease Control and Prevention in the United States continue to promote the wearing of masks at large indoor gatherings or when infection rates rise. Masking is now voluntary in almost all non-medical settings. While we need to be respectful of those who choose to wear a mask, there is little current evidence of routine benefit. Masks should be worn by those infected to reduce droplet spread to others. As well, those who feel at high risk from infection may choose to continue to wear a mask indoors despite the lack of high-quality data as to benefit. However, the benefit is limited by the ongoing risk of infection from close interaction with family and friends. Is it worth the challenges of social isolation?
Early in the pandemic, attempts at using barrier protection to limit spread seemed reasonable even without the support of scientific evidence. Now the science no longer supports its use by non-infected people. We have had three years of the effects of social isolation on our mental health. Lower burden of disease, vaccinations and antivirals have greatly reduced the risk of infection, hospitalization or mortality. It is now time to live free of masks.
National Post
Dr. Harry Rakowski is an academic Toronto cardiologist and commentator.
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