Did Saskatchewan's vaccine mandate work? This study may tell us.

Saskatchewan's COVID-19 vaccine mandate last fall resulted in 49,700 more people getting their first dose over a month and a half, a study from Simon Fraser University has found.

It appears that vaccine mandates had the biggest effect in areas with the lowest vaccine uptake, according to Shih En Lu, an associate professor of economics who studies game theory. And Saskatchewan and Alberta had the lowest first-dose vaccination rates at the time.

On Sept. 16, 2021, Premier Scott Moe announced an indoor masking policy, to come into effect the next day, and a vaccine mandate to be implemented Oct. 1.

By Oct. 31, about 88 per cent of eligible Saskatchewan residents had at least one shot. The researchers estimated that number would have been 83 per cent without the vaccine mandate — a five percentage point difference.

"We can't say that for sure, but it certainly looks like that from our results just because there are more potential people to be affected. If the vaccination rate is 60 per cent, then 40 per cent of people are potentially restricted by this policy. At the extreme, right, if the vaccination rate were 100 per cent? Well, obviously, the policy would have zero effect, because everybody's already vaccinated," Lu said.

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Saskatchewan's mask mandate was tied with New Brunswick for packing the biggest punch among the provinces.

The team used data from the 10 provinces and three European countries that implemented vaccine mandates from July to September of 2021.

Each province's mandate took effect at a different time, which allowed the team to study their effects, Lu said.

"Because you could imagine if, say, the entire country adopted proof of vaccination mandates at the same time and you see a spike in vaccinations, you wouldn't really know if the spike is because of the policy or because of something else that happened at the same time.

"But if the implementation time varies across the country, and in each jurisdiction you see that the vaccination rates increase, or the pace of vaccination increases after the adoption of a proof of vaccination mandate, then you can be more certain that it's actually because of the policy."

The study found that across the country vaccine mandates led to 979,000 extra first doses, though Lu noted a wide degree of uncertainty with that estimate.

"Even though as a percent of the population might not be huge, I think that's still a very significant number," he said.

Lu said the results of the study could be relevant if another severe variant like Delta appears and booster vaccines were known to provide protection.

"We know that booster uptake in Canada is quite low right now, so if the government were to impose a booster mandate, you have to have had at least two doses and your most recent dose must be say, within the past six months or something, then that would potentially have a very large impact, right?

"But of course, politically that night, you know, it's kind of a paradox. The fewer people are vaccinated, the more impactful the policy is going to be. But at the same time, the harder politically it would be to implement the policy because then you would be forcing more people to go get a shot that they wouldn't have otherwise gotten.

"So that's something that politicians and public health people can weigh. But you know, on our end, I think I think it suggests that if need be this is a policy in the toolbox that may have an even larger impact for boosters."

The study was published this month in Nature Human Behaviour.

Lu and his colleagues previously published a study showing that public indoor masking mandates in Ontario during the summer of 2020 were associated with a 22 per cent weekly reduction in new COVID-19 cases.