Health agencies in Canada and the U.S. have now done a 180-degree turn on their previous advice that healthy people should not wear homemade face masks.
Dr. Theresa Tam, Canada’s public health officer, in the past has opposed the use of homemade masks, arguing that they give people a false sense of security and that people might spread infection when they remove the masks. She continues to make those arguments.
But facing pressure as a growing number of countries introduce requirements for face covering in public, along with growing evidence that homemade masks can help when used in conjunction with physical distancing and hand washing, Tam relented on Monday (April 6).
“Wearing a non-medical mask is an additional measure that you can take to protect others around you,” Tam said Monday. “A non-medical mask can reduce the chance of your respiratory droplets coming into contact with others or landing on surfaces.”
Tam insisted as recently as March 30 that “putting a mask on an asymptomatic person is not beneficial.”
She has long downplayed growing evidence that the virus causing Covid-19 can be spread by people who have not yet developed symptoms (presymptomatic) or whose symptoms never become noticeable (asymptomatic).
She told the House of Commons Health Committee on Jan. 29 that asymptomatic transmission, “is, we believe, a rare event. It is not that type of transmission that drives the force of an epidemic.” She has continued to make similar assertions.
In her statement Monday, Tam backpedaled a bit, acknowledging that: “We still do not know how big a role presymptomcatic and asymptomatic transmission play in driving this pandemic, but we know that it is occurring.”
She claimed evidence of presymptomatic and asymptomatic transmission only came to light in the last 10 days or so, even though there’s been evidence since January in Asian countries that experienced the virus first.
The decision to reverse position on masks was made jointly by the Special Advisory Committee, which consists of Tam and provincial senior health officials.
The Public Health Agency of Canada has also updated its website information on the use of homemade masks.
Authorities continue to advise that medical-grade masks such as N95 respirators, which are in short supply, should be reserved for front-line health workers and other essential workers who require them.
Last week the U.S. Centers for Disease Control and Prevention (CDC) also reversed itself and is now advising people to “use cloth face coverings to help slow the spread of Covid-19.”
A CDC web page now advises the public on how to make and use homemade face coverings.
CDC also has a Q&A (FAQ) page answering questions about the use of homemade masks.
U.S. President Donald Trump announced the new CDC policy last week, but said he will not wear a mask himself. His Democrat challenger Joe Biden said he will wear one in public.
In both Canada and the U.S., mask wearing in public continues to be voluntary. In a growing number of countries, it is mandatory.
Health authorities say homemade masks are intended to stop carriers of the virus from spreading it to others rather than to protect mask wearers from breathing in the infected droplets of others with the disease. They have not provided evidence that the virus only travels in one direction through cotton fabric, but cloth is less effective at stopping smaller droplets and is not recommended for protection against the virus in aerosol form.
See previous stories (links below) on OsoyoosPersists.ca on the use of homemade masks and the growing evidence that they provide partial protection when properly used in combination with physical distancing and hand washing.
- “Update: There’s growing push-back against message that public should not wear masks” – OsoyoosPersists.ca, April 1, 2020.
- “Homemade face masks offer limited protection, but if used properly, they’re better than nothing” – OsoyoosPersists.ca, March 25, 2020.
This CBC story, “Canada’s top doctor says non-medical masks can help stop the spread of COVID-19,” has additional details as well as a video clip of Tam making her remarks Monday.
This Globe and Mail story, “Tam offers new advice: wear a non-medical mask when shopping or using public transit,” also covers Tam’s comments today.