Canadian health officials have changed their mask recommendation several times since the pandemic first arrived in January, but they're now officially recommending the use of non-medical masks in places where social distancing is difficult or impossible.

Canada's chief public health officer, Dr. Theresa Tam, made the announcement during a press briefing this afternoon and said that while this isn't a huge change from previous comments on mask usage, it's now an official recommendation as opposed to prior statements that were more "permissive." 

"Where COVID-19 activity is occurring, use of non-medical masks and face coverings is recommended as an added layer of protection when physical distancing is difficult to maintain," Dr. Tam said Wednesday. 

"And staying home when sick is a must, always and everywhere."

She emphasized that mask usage should be in addition to hand washing, physical distancing and cough etiquette —  all of which are considered the bare minimum when it comes to virus prevention. 

I wear a Mask to protect you why not wear a Mask to protect me. Help stop the spread of #COVID19 pic.twitter.com/hNiipKBxuW

— 🍁 Merlin 🍁🐨🦜🦘 (@MerlinofCanada) May 20, 2020

Prime Minister Justin Trudeau also mentioned the new mask recommendation during his press conference this morning, saying he now wears a mask when he's out of the house and can't be two metres away from others at all times.

The PM just arrived on Parliament Hill wearing a mask. He says Canada's public health officials will make an announcement on masks shortly. pic.twitter.com/vo8qfznkLt

— Sarah Sears (@iamSas) May 20, 2020

Meanwhile, many have criticized Canada for lagging behind other countries when it comes to mask recommendations and guidelines.

Canada initially recommended against the usage of masks altogether back in January, but later updated that recommendation when it was discovered that the virus can be spread asymptomatically. 

Health officials have since said masks can be effective in preventing the person wearing it from spreading the virus to others, but only when used safely and effectively. 

But some experts have continued to call for much stronger mask policies and guidelines in Canada, including one Toronto doctor whose been particularly outspoken about their value. 

My latest article: The Mystery of Masks in #Canada’s #COVID19 response 😷🇨🇦

-Should masks be mandatory?
-How to reduce social disparities & discrimination
-Addressing mask-shaming & common concerns#Masks4Canada #Masks4All #COVID19Canadahttps://t.co/bUSiyAgAsS

— Dr. Jennifer Kwan (@jkwan_md) May 14, 2020

 "We know that masks are an effective intervention against other respiratory viruses. We know that masks catch droplets from the wearer's nose and mouth, while they are breathing, speaking, coughing, or sneezing, and are an effective form of source control. My mask protects you, and your mask protects me. Research models predict that if 80% of people wore a mask, then COVID19 infections would drop to 1/12th the number of infections, compared to if nobody wore a mask," wrote Dr. Jennifer Kwan in a blog post about masks in Canada.

"Masks are not a perfect intervention — but neither are influenza vaccinations, and we still recommend them annually. They are cost-effective — it is estimated that each cloth mask for the public can lead to savings of $3000–6000 USD each by reducing the spread and morbidity of COVID19. Masks can help save lives and reduce the economic impact of COVID19."

Meanwhile, Dr. Tam said the government will be posting updated official non-medical mask recommendations and guidelines online later today.