Use of masks during COVID-19 not always the answer, says epidemiologist

As New Brunswick continues to reopen for business, the use of masks is being strongly recommended by the government when physical distancing cannot be maintained.

Dr. Jennifer Russell, New Brunswick's chief medical officer of health, said anyone who cannot keep an effective physical distance during COVID-19 should wear a mask. Some exceptions include children under two and people who can't wear a mask because of breathing troubles.

But Dr. Colin Furness, an infection control epidemiologist and assistant professor at the University of Toronto, says wearing a mask can be dangerous. That is if the wrong mask is worn, it's worn incorrectly or people have incorrect expectations when wearing it. 

"The worst one is wearing one for too long," he said, noting masks can collect bacteria and other viruses.

Furness said he wonders why this information isn't being shared when there is evidence about it.

Study points to dangers

He said a study in a U.K. medical journal showed health-care workers who wore cloth masks all day while working were 13 times more likely to get a respiratory illness when compared to the standard practice of only wearing a mask when necessary. 

Those who wore a paper or procedure mask were twice as likely to get some type of respiratory infection if they wore it all day. The N95 masks were only worn when required during the study and no staff were affected. 

"This shouldn't surprise us," Furness said. "A mask, you're breathing on it all day long creating all this wonderful space for bacteria to multiply, and once they get to a certain quantity you start inhaling them."

He said drug-resistant bacteria could be worse than COVID-19 for some people.

More information on wearing masks needed

Furness said he despairs at advice around use of masks, adding it makes people feel safe because they are doing it to protect themselves.

"I'm not anti-mask," he said, noting he is against use without "accompanying literacy."

Furness said many think wearing a mask all day long makes the most sense to stay safe, but it's not. "It's counterintuitive and that can be harmful for people." 

While both the Public Health Agency of Canada and Russell began recommending last month that people wear masks, they urged that N95 and surgical masks be left for the health-care community.

The World Health Organization does not officially recommend the general public use masks as a way to reduce spread, only saying that if people decide to use masks they should do so "safely and properly." 

"We encourage countries that are considering the use of masks for the general population to study their effectiveness, so we can all learn from their experience," a spokesperson for WHO said in a statement to CBC News. 

Public Health in New Brunswick has shared information about the proper way to wear a mask and remove it.

But the department emphasizes the importance of physical distancing, handwashing and proper cleaning to reduce the spread of the virus in a province that's managed to flatten the curve. 

Russell said masks should not be made out of plastic or other "non-breathable materials," or paper tissues that can easily fall apart.

Residents who can't find or purchase a mask, can make masks out of cloth such as cotton bandanas or T-shirts. They can be secured with the help of elastics, string, rubber bands or hair ties. 

Limit time of wearing

Furness said if a person has to wear a cloth mask, it should be made of heavy cotton fabric. The wearer should time how long they have it on.

"I will only wear it for two hours total wearing time," Furness said.

That's an arbitrary number Furness has chosen, but he said a published study indicates four hours is too long. He boils his masks after two hours of use.

He said people should never wear masks outside or in the car. 

"I'm wearing it only when I'm in an indoor place … that's got lots of people," he said. "Grocery stores are high on my list because social distancing is really hard when those aisles are narrow and everyone is a little bit tense."

Masks shouldn't be safety net

But Furness said people have to know they are wearing masks for the right reasons and not to get a false sense of security. 

"I caught myself the first time I had mine on and was walking around the grocery store thinking I'm safe now. I know a fair bit about this stuff and I know that's not really true." 

Furness said he got a sense that might be how others were acting as well. 

When he does talk to people about why they are wearing a mask, he is not hearing what he expected to hear. 

"I'm hearing I want to be safe for me, so people are clearly oriented that way." 

He said that is worrying because if people are wearing masks and feeling safe, then that will displace physical distancing. 

"It's like, it's OK, we're wearing masks, we can be close together. That's what I worry about and I can't say I have hard proof but it is certainly cause for concern."