There’s a growing international movement advocating the use of homemade face masks in the fight against the spread of Covid-19.
As pointed out in a story last week about masks on OsoyoosPersists.ca, the official line from such respected organizations as the Public Health Agency of Canada (PHAC), the U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) is that the general public should not wear masks unless they are infected or are caring for someone with the virus.
But a report yesterday (March 31) in the Washington Post suggests the CDC may be reconsidering this advice. Other countries, such as the Czech Republic, have rapidly switched from almost no public wearing of masks to generalized public use.
The argument against widespread use of masks boils down to three points:
- They give a false sense of security because they are of limited effectiveness;
- When they are misused, they can actually increase the risk of infection;
- They are in short supply and should be saved for those who really need them.
Advocates of public mask use, such as artificial intelligence researcher Jeremy Howard, point out that these arguments are spurious. Howard made the case in a March 27 article in the Washington Post.
“We give cars anti-lock brakes and seat belts despite the possibility that people might drive more riskily knowing the safety equipment is there.” – Jeremy Howard
The obvious answer to the first and second concerns are public education. Social distancing and rigorous hand washing are still absolutely necessary, whether or not you choose to wear a mask. And the safe method of putting on, wearing and removing a mask can be taught.
The answer to the third point is obviously that people should not use commercial masks unless they are front-line healthcare workers or others who need them. Homemade masks are NOT as effective as real surgical masks, but a cotton homemade mask, if used properly, is significantly more effective than nothing.
As noted in last week’s story, a mask made from a cotton t-shirt can filter 51 per cent of 0.02 micron particles and 69 per cent of one-micron particles, according to research done at University of Cambridge in the UK in 2013. That’s not good enough for a hospital setting, but for a quick visit to a grocery store, and combined with social distancing and hand washing, it’s a lot better than no mask.
One of the strongest voices in Canada against wider use of masks has been Dr. Theresa Tam, Canada’s Chief Public Health Officer. But Tam has long downplayed the risk of asymptomatic transmission of the virus, despite growing evidence that a significant cause of spread of the virus is by people not yet showing symptoms.
This article yesterday from CBC, “Some health experts questioning advice against wider use of masks to slow spread of COVID-19,” shows a video clip of Tam making her argument, and carries a strong rebuttal from Dr. K.K. Cheng, director of the Institute of Applied Health Research at the University of Birmingham in the U.K.
“The important thing about this coronavirus is that some patients start to shed virus, and become infectious, even before they have symptoms,” Dr. K.K. Cheng, University of Birmingham, U.K.
Indeed, a major difference between SARS-CoV-2, the virus causing Covid-19, and SARS-CoV-1, the virus causing the 2003 SARS outbreak, is asymptomatic transmission. And that’s a major reason that Covid-19 is much more deadly than SARS.
UPDATE April 1: OsoyoosPersists.ca checked with the Public Health Agency of Canada on Wednesday whether Dr. Tam’s position on asymptomatic transmission had changed since her Jan. 29 statement, and if so, what her current position is.
A PHAC spokesperson did not answer the question directly, but did say in part:
“While experts believe that spread from a person who is asymptomatic (i.e. not showing any symptoms) is possible, this is has been the subject of scientific debate and is difficult to confirm.
“Monitoring an asymptomatic individual who is a contact of someone with COVID-19 and recommending 14-day self-isolation does more to prevent the spread of the virus than a potentially false negative test result.
“Canada has and will continue to test all symptomatic individuals, as part of our evidence-based containment strategy, while considering the evolving science on other testing scenarios. As the science evolves, our approach will keep pace, and policies and protocols will be updated accordingly,” PHAC spokesperson.
UPDATE April 1: Dr. Tam made further comments on use of masks Wednesday. See the video clip in this story on CBC.
“Unfortunately, the top-down conversation around masks has become a case study in how not to communicate with the public, especially now that the traditional gatekeepers like media and health authorities have much less control. The message became counterproductive and may have encouraged even more hoarding because it seemed as though authorities were shaping the message around managing the scarcity rather than confronting the reality of the situation,” – Zeynep Tufekci, University of North Carolina
She points to the obvious contradiction in the messaging that masks are needed for healthcare workers, but would not help the public.
“How do these masks magically protect the wearers only and only if they work in a particular field?,” she asked.
Asian countries that have dealt with the virus earlier than North America are emphasizing the importance of mask wearing by the public.
Science Magazine published an interview on March 27 with George Gao, director-general of the Chinese Center for Disease Control and Prevention, whom they’ve been hounding for an interview over the past two months. His message was blunt:
“The big mistake in the U.S. and Europe, in my opinion, is that people aren’t wearing masks. This virus is transmitted by droplets and close contact. Droplets play a very important role—you’ve got to wear a mask, because when you speak, there are always droplets coming out of your mouth. Many people have asymptomatic or pre-symptomatic infections. If they are wearing face masks, it can prevent droplets that carry the virus from escaping and infecting others,” – Dr. George Gao, director-general, Chinese Center for Disease Control and Prevention
Yuen Kwok-yung, a Hong Kong infectious disease expert, also supports the use of masks in an article published by the Straits Times of Singapore, originally published by Caixin Global.
“We can only rely on telling everyone to wear a mask, wash their hands frequently, use alcoholic sanitizer,” he said. “Wear a mask to protect not only yourself but also others, because if you are infected but asymptomatic, you could still stop the spread by wearing a mask.”
It appears some of the resistance in North America to Asian lessons about universal mask wearing is cultural. In many Asian countries, wearing of masks in public has been the norm for many years. In North America, there’s a perception that the only people wearing masks in public are those who are already sick. In Asia, it’s done for prevention.
But attitudes can change rapidly. The Czech Republic is a great example. In a matter of days, it went from being a country with almost no public use of masks to a country where they are now worn by the general population. As of March 18, wearing a face covering in public has been compulsory.
The result has been a “flattening” of the pandemic’s growth.
Some of the credit for that goes to Petr Ludwig, a Czech writer whose field of interest is critical thinking. This video he posted talks about the approach taken in Czechia, the Czech Republic.
“When we both have a face mask, I protect you, you protect me,” says the young woman in the video. “And we both are safe.”
The video emphasizes that people in Czechia still practice the necessary steps of social distancing and hand washing.
“I recommend to all fellow ministers and governments to implement population-wide use of face masks, even homemade ones,” said Adam Vojtech, Minister of Health of the Czech Republic at the end of the video. “Today we see that this is one of the most important decisions that we have made. And if it helps here, it can help anywhere.”
UPDATE April 1: Japan announced on Wednesday, April 1 that it is distributing reusable cloth masks to 50 million households.
Opponents of cloth face masks point to a 2015 study in Vietnam where healthcare workers using these masks experienced higher rates of infection due to moisture retention and poor filtration. But working all day in a high-risk ward is not analogous to short-term use of a cloth face mask to enter a business or take a short ride on public transit while also social distancing and hand washing.
A graph by writer Joseph Perla (@jperla) showing the difference between growth curves in countries where masks are not widely used in public compared with countries such as South Korea, Japan, Singapore and Hong Kong, where masks are widely worn is illustrative.
While other factors may also be at play, and correlation doesn’t prove cause, countries with widespread use of masks have been more successful at flattening the curve.
Contrary to the advice of PHAC, CDC and WHO, this advice on masks from Japan’s Ministry of Health, Labour and Welfare may be a better and more credible message:
“If you have symptoms such as coughing and sneezing, wearing a face mask is proved to be highly effective in catching the droplets, and therefore might help prevent the spread of viruses.
“The effectiveness of wearing a face mask to protect yourself from contracting viruses is thought to be very limited. If you wear a face mask in confined, badly ventilated spaces, it might help avoid catching droplets emitted from others, but if you are in an open-air environment, the use of face mask is not very efficient.” – Japan Ministry of Health, Labour and Welfare
A recent report in the medical journal, The Lancet, titled “Rational use of face masks in the Covid-19 pandemic,” compares the conflicting messages between health authorities in different countries.
“Perhaps it would also be rational to recommend that people in quarantine wear face masks if they need to leave home for any reason, to prevent potential asymptomatic or pre-symptomatic transmission. In addition, vulnerable populations, such as older adults and those with underlying medical conditions, should wear face masks if available,” – various researchers in The Lancet
As for the British researchers who did the study on effectiveness of materials such as cotton t-shirts at intercepting viruses back in 2013, their conclusions are worth quoting in full:
“A protective mask may reduce the likelihood of infection, but it will not eliminate the risk, particularly when a disease has more than 1 route of transmission. Thus any mask, no matter how efficient at filtration or how good the seal, will have minimal effect if it is not used in conjunction with other preventative measures, such as isolation of infected cases, immunization, good respiratory etiquette, and regular hand hygiene.
“An improvised face mask should be viewed as the last possible alternative if a supply of commercial face masks is not available, irrespective of the disease against which it may be required for protection.
“Improvised homemade face masks may be used to help protect those who could potentially, for example, be at occupational risk from close or frequent contact with symptomatic patients. However, these masks would provide the wearers little protection from microorganisms from others persons who are infected with respiratory diseases. As a result, we would not recommend the use of homemade face masks as a method of reducing transmission of infection from aerosols.”
Views differ on the likelihood that this virus, SARS-CoV-2, is transmitted as an aerosol, but the use of N95 respirators helps to protect healthcare workers in close quarters where aerosol transmission might occur. It’s much less likely to occur on a short trip to your local grocery store.
UPDATE April 2: This article, “Everyone thinks they’re right about masks,” in the Atlantic addresses the question of aerosol transmission.
Me personally? Everybody’s situation is different so this is not advice.
I’ve recently passed the threshold age of 65, don’t have perfect health but am well enough that I can shop for myself, as can most people my age.
I’m trying to keep trips out to any store to once every two weeks for groceries and much longer for other items like the pharmacy. But then I don’t have ravenous children to feed and some people need to shop more often.
My partner gave me some bandanas and I put on a clean one, wrapping it to three layers, and tying its ends together behind my head above the ears. After a single use, I put it in the laundry box and wash my hands thoroughly.
People look at me as if saying, “You don’t need that and you look ridiculous.”
I don’t care. I still keep two metres away from other people, even if it means some sharp moves with the grocery cart. The bandana reminds people to social distance from me — I probably look like a scary bandit. If the bandana keeps people away from me, that in itself is a benefit.
Of course I wash my hands thoroughly as soon and often as possible. The young woman cashier at Buy-Low Foods even offered me a squirt of hand sanitizer, which I’m surprised still exists.
I told her I was smiling under my bandana.
Stay healthy. Keep your distance. Wash your hands. And I’ll cover my eyes, nose and mouth.