A man wears a face mask as he looks at a COVID-19 information sign in Montreal, Sunday, Sept. 20, 2020, as the COVID-19 pandemic continues in Canada and around the world. THE CANADIAN PRESS/Graham Hughes

Preliminary B.C. study results suggest mask mandates can lower COVID-19 spread by 25%

Study has not yet been printed or peer reviewed

Preliminary results from a study conducted by Simon Fraser University researches suggests that a mask mandate can lower the transmission of COVID-19 by 25 per cent each week.

Study results, released prior to peer review on Wednesday (Oct. 7), show that mandating masks indoors nationwide in early July could have reduced new weekly cases by 25 to 40 per cent in mid-August. That would translate approximately to 700 to 1,1000 fewer cases each week.

Researchers from SFU’s economics department focused on mask mandates brought in across Ontario’s 34 Public Health Units over the course of two months this year. Results from comparing units that went to mask mandates early, versus later, showed that earlier adoption was association with an average weekly reduction of 25 to 31 per cent, in July and August. There has been no mask mandate province-wide in B.C., although many government buildings, grocery stores and other businesses have brought in mask rules of their own.

ALSO READ: B.C. records 102 new COVID-19 cases, 2 deaths

The results of SFU’s study differed from an earlier one about mask mandates in the U.S., which found a nine to 10 per cent reduction in new cases.

“One possible explanation is that Ontario’s mask policy is more comprehensive: we evaluate the effect of universal indoor mask-wearing for the public rather than the effect of mask wearing for employees only in [the U.S. study]. Differences in the compliance rate may also contribute to this difference,” researchers noted.

An analysis of mask mandates across the country found a reduction in new cases of up to 46 per cent in the first weeks after adoption. Researchers also saw that mask mandates increased self-reported use by 30 per cent.

“Jointly, these results suggest that mandating indoor mask wear in public places is a powerful policy measure to slow the spread of COVID-19, with little associated economic disruption in the short term,” the study concluded.

Researchers also looked at COVID-19 restrictions and their effect on new cases. They found that the most stringent restrictions were associated with a decrease of 48 to 57 per cent in weekly cases.

Study authors noted that while the results are significant, “their sample period does not allow them to definitively say whether the effect of mask mandates persists or weakens beyond the first few weeks after implementation.”

ALSO READ: Anti-mask protest at Kelowna schools ‘disappointing,’ says superintendent


@katslepian

katya.slepian@bpdigital.ca

Like us on Facebook and follow us on Twitter.

Want to support local journalism during the pandemic? Make a donation here.

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Alberta has 3,651 active cases of COVID-19. (File photo)
432 new COVID cases sets another record Friday

Central zone holds steady at 126 active cases

"We are looking seriously at the spread and determining what our next steps should be," says Alberta’s chief medical officer of health, Dr. Deena Hinshaw, as the daily number of COVID-19 cases continues to climb.
427 new COVID cases is highest in Alberta ever

Central zone has 126 active cases of COVID-19

RCMP. (Black Press File Photo)
Calgary man dies in two-vehicle collision near Sylvan Lake

A semi truck collided with a SUV just east of Hwy. 781 on Hwy 11.

Shaelynn Decock and her dog Taco, who has been missing since Aug. 26. Photo Submitted
Sylvan Lake woman looking for closure for her stolen dog

Shaelynn Decock says it has been two months since she last saw her dog Taco

Alberta chief medical officer of health Dr. Deena Hinshaw updates media on the Covid-19 situation in Edmonton on Friday March 20, 2020. nbsp;Alberta is reporting it's highest daily number of COVID-19 cases, with 364 new infections. THE CANADIAN PRESS/Jason Franson
Alberta confirmed 323 COVID-19 cases Tuesday

Central zone active cases at 145

B.C. Liberal leader Andrew Wilkinson, B.C. NDP leader John Horgan and B.C. Greens leader Sonia Furstenau. (Black Press Media)
VIDEO: One day until B.C. voters go to the polls in snap election defined by pandemic

NDP Leader John Horgan’s decision to call an election comes more than a year ahead of schedule and during a pandemic

Comedic actor Seth Rogen, right, and business partner Evan Goldberg pose in this undated handout photo. When actor Seth Rogen was growing up and smoking cannabis in Vancouver, he recalls there was a constant cloud of shame around the substance that still lingers. Rogen is determined to change that. (Maarten de Boer ohoto)
Seth Rogen talks about fighting cannabis stigma, why pot should be as accepted as beer

‘I smoke weed all day and every day and have for 20 years’

Leader of the Opposition Erin O’Toole rises during Question Period in the House of Commons Thursday October 22, 2020 in Ottawa. THE CANADIAN PRESS/Adrian Wyld
O’Toole tells Alberta UCP AGM Liberals were ‘late and confused’ on COVID response

He says Alberta Premier Jason Kenney has taken charge and not waited to make things happen

Alberta Premier Jason Kenney arrives for an announcement at a news conference in Calgary, Alta., Tuesday, Sept. 15, 2020. THE CANADIAN PRESS/Todd Korol
Inquiry into oil and gas foes to deliver report next year: Kenney

A lawsuit filed by environmental law firm Ecojustice argues the inquiry is politically motivated

The Canadian border is pictured at the Peace Arch Canada/USA border crossing in Surrey, B.C. Friday, March 20, 2020. More than 4.6 million people have arrived in Canada since the border closed last March and fewer than one-quarter of them were ordered to quarantine while the rest were deemed “essential” and exempted from quarantining. THE CANADIAN PRESS/Jonathan Hayward
Majority of international travellers since March deemed ‘essential’, avoid quarantine

As of Oct. 20, 3.5 million travellers had been deemed essential, and another 1.1 million were considered non-essential

This photo provided by Air Force Reserve shows a sky view of Hurricane Epsilon taken by Air Force Reserve hurricane hunter team over the Atlantic Ocean taken Wednesday, Oct. 21, 2020.   Epsilon’s maximum sustained winds have dropped slightly as it prepares to sideswipe Bermuda on a path over the Atlantic Ocean.  The National Hurricane Center says it should come close enough Thursday, Oct. 22, evening to merit a tropical storm warning for the island.  (Air Force Reserve via AP)
Hurricane Epsilon expected to remain offshore but will push waves at Atlantic Canada

Epsilon is not expected to have any real impact on land

A voter places her absentee ballot in the ballot box, Wednesday, Oct. 7, 2020, at Merrill Auditorium in Portland, Maine. THE CANADIAN PRESS/AP/Robert F. Bukaty
American voters living in Canada increasingly being counted in presidential race

The largest number of Canadian-based American voters cast their ballots in New York and California

A composite image of three photographs shows BC NDP Leader John Horgan, left, in Coquitlam, B.C., on Sept. 25, 2020; BC Green Party Leader Sonia Furstenau, centre, in Victoria on Sept. 24, 2020; and BC Liberal Party Leader Andrew Wilkinson Pitt Meadows, B.C., on Sept. 24, 2020. THE CANADIAN PRESS/Darryl Dyck, Chad Hipolito
British Columbia votes in snap election called during COVID-19 pandemic

NDP Leader John Horgan called the snap election one year before the fixed voting date

Nunavut's provincial flag flies on a flag pole in Ottawa, on Tuesday June 30, 2020. The annual report from Nunavut's representative for children and youth says "complacency and a lack of accountability" in the territory's public service means basic information about young people needing services isn’t tracked. THE CANADIAN PRESS/Adrian Wyld
Nunavut’s young people ‘should be expecting more’ from government services: advocate

‘The majority of information we requested is not tracked or was not provided by departments’

Most Read