Recently, the World Health Organization (WHO) reversed its' original stance against face masks, "If you are healthy, you only need to wear a mask if you are taking care of a person with COVID-19"; and now recommends wearing masks of different types in various settings by various people.
An increasing number of governments around the world are imposing mandatory face mask policies.
What does the science say?
Effectiveness of Fabric Masks for the COVID-19 Pandemic
A study published by the National Academies of Sciences, Engineering and Medicine entitled "Rapid Expert Consultation on the Effectiveness of Fabric Masks for the COVID-19 Pandemic (April 8, 2020)" concluded that, "The evidence from these laboratory filtration studies suggests that such fabric masks may reduce the transmission of larger respiratory droplets. There is little evidence regarding the transmission of small aerosolized particulates of the size potentially exhaled by asymptomatic or presymptomatic individuals with COVID-19." It went on to say, "The extent of any protection will depend on how the masks are made and used. It will also depend on how mask use affects users' other precautionary behaviors...Those behavioral effects may undermine or enhance homemade fabric masks' overall effect on public health. The current level of benefit, if any, is not possible to assess." Dr. Michael Osterholm of the Center for Infectious Disease Research and Policy (CIDRAP), who contributed to the paper, said, "Because aerosols likely play an important role in coronavirus transmission, cloth masks will do little, if anything, to limit spread of the disease."
In 2015, The British Medical Journal published the results of a study by Professor Raina McIntyre of the University of New South Wales entitled "A cluster randomised trial of cloth masks compared with medical masks in healthcare workers". It found that filtration in cloth masks is extremely poor and may actually increase the likelihood of infection, "Laboratory tests showed the penetration of particles through the cloth masks to be very high (97%) compared with medical masks (44%)…The virus may survive on the surface of the face-masks, and modelling studies have quantified the contamination levels of masks. Self-contamination through repeated use and improper doffing is possible. For example, a contaminated cloth mask may transfer pathogen from the mask to the bare hands of the wearer. We also showed that filtration was extremely poor (almost 0%) for the cloth masks."
Responding to queries from concerned health care workers in March, McIntyre said, "As authors of the only published randomised controlled clinical trial of cloth masks, we have been getting daily emails about this from health workers concerned about using cloth masks. The study found that cloth mask wearers had higher rates of infection than even the standard practice control group of health workers, and the filtration provided by cloth masks was poor compared to surgical masks."
Cloth masks then are almost completely ineffective
An earlier 2011 review by the UK Health Protection Agency of seventeen previous studies concluded, "None of the studies established a conclusive relationship between mask/respirator use and protection against influenza infection."
Cloth masks then are almost completely ineffective, may result in higher rates of infection due to self-contamination through improper handling and behaviour, and cannot be recommended on the basis of any existing scientific studies.
If this seems counterintuitive, the answers lie in Physics and Biology.
The primary methods of virus transmission are Respiratory, Aerosol and Contact.
Respiratory transmission can occur when "respiratory droplets" are spread by a symptomatic person through sneezing or coughing. Respiratory droplets are relatively large (>5 microns) and fall to the ground quickly (hence the two-metre distancing rule).
Aerosol particles however are much smaller (<5 microns), can remain suspended in the air for much longer and travel much further. A study published in April by the New England Journal of Medicine found that, "…aerosol and fomite transmission of SARS-CoV-2 is plausible, since the virus can remain viable and infectious in aerosols for hours and on surfaces up to days..." A 2011 study by Wang (et al) showed, "On average, 64 per cent of the viral genome copies were associated with fine particles smaller than 2.5 µm (microns), which can remain suspended for hours."
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Surgical facemasks are intended to shield patients from sneezing or coughing by medical workers
The average pore size of face masks is between 80 and 500 microns, far too large to prevent filtration of COVID-19 infected particles.
Surgical facemasks are intended to shield patients from sneezing or coughing by medical workers while administering treatment, but do not completely filter all droplets. Since the minimum-infective-dose is smaller than one aerosol particle, they cannot prevent disease transmission.
Conflicting with previous research, an April 2019 study published in Nature Research found that, "Surgical face masks significantly reduced detection of influenza virus RNA in respiratory droplets and coronavirus RNA in aerosols, with a trend toward reduced detection of coronavirus RNA in respiratory droplets."
Mandatory masking serves a self-protective regulatory dynamic biased toward extreme risk-aversion, and you may feel safer wearing one, but there is little supporting empirical science behind it.
On a positive note, as John Wesley said in 1791, "cleanliness is indeed next to godliness"…and most moms support hand-washing.
Ken Grafton is a writer living by the river in Aylmer, Quebec, just downwind from Parliament Hill; with global executive-level experience in engineering and telecommunications. His work has been published in The Hill Times, National Newswatch, National Observer, Canadian Dimension, The Hamilton Spectator, The Welland Tribune, The Peterborough Examiner, The St. Catherines Standard, The Niagara Falls Review, The Waterloo Region Record, The Burlington Post, The Ontario Times, The Muskoka Times, Cambridge Times, The New Hamburg Independent, Hamilton News, Progressive Bloggers, Global News and The Low Down to Hull and Back.
Recently, the World Health Organization (WHO) reversed its' original stance against face masks, "If you are healthy, you only need to wear a mask if you are taking care of a person with COVID-19"; and now recommends wearing masks of different types in various settings by various people.
An increasing number of governments around the world are imposing mandatory face mask policies.
What does the science say?
