Mandatory masks make impact on COVID

Face-coverings cut cases by 25%, study finds

Mask mandates in Ontario during the COVID-19 pandemic may have reduced new weekly cases by as much as 25 per cent, a team of economists from Simon Fraser University found.

The researchers also found that mask mandates dramatically increased mask usage in Canada, with self- reported mask- wearing jumping by 30 percentage points after mandates were introduced. Like almost all non- pharmaceutical measures to fight the pandemic, mask mandates hinge entirely on public compliance.

The economists also found that a nationwide mask mandate instituted in mid- July would have reduced weekly cases by 25 to 40 per cent by mid- August. That would have resulted in between 700 and 1,100 fewer weekly cases in Canada.

The new data comes as masks have become an unlikely flashpoint for controversy during the COVID-19 pandemic. Earlier in the year, public health experts gave conflicting recommendations about mask- wearing by initially warning that they could cause a false sense of security. As the public health advice shifted toward mask-wearing, protests popped up around the world arguing that mask mandates were an abrogation of basic rights.

The research was released Monday as a working paper at the National Bureau of Economic Research, before peer review, and expands on similar research being conducted in the United States and Germany.

Due to its large population of more than 15 million people and 34 public health units, which introduced mask mandates at different times, Ontario is a particularly good place to study the impact of masks while controlling for other factors.

Mask mandates were first introduced in the province in the health unit around Guelph on June 12 and last in the Northwestern public health unit on August 17. The only health unit without a mask mandate in Ontario is Lambton although Sarnia, its largest city, has its own mandate.

The study also finds some less reliable, “noisy,” data about the effects of other measures, like limiting businesses and closing workplaces, on reducing COVID-19 cases.

That means that as these other measures are lifted, they can cancel out the effects of mask-wearing.

“Reduced restrictions and the associated increase in business or workplace activity and gathering or school reopening can offset, in whole or in part, the estimated effect of mask mandates on COVID-19 case growth,” the paper reads.

MASK MANDATES WERE FIRST INTRODUCED IN JUNE.

Due to the limited time available to study the fast- moving pandemic, the researchers can’t say for sure that the effect lasts longer than a few weeks. But at the very least, they found that masks can be “a powerful tool” for temporarily reducing the spread of COVID-19.

The paper builds on work by two other research papers on the topic. A study on mask-wearing by employees in public- facing businesses found that these kind of mandates are associated with a 10 per cent decrease in the weekly growth rate of COVID-19 cases.

Another study on mask mandates in Germany found that these measures caused a 40 per cent decline in the weekly growth rate of COVID-19 cases.