MONTREAL—The federal government is backing down from its vaccine mandate for Canadian truckers three days before it was set to take effect. Ottawa announced in mid-November that truck drivers crossing into Canada would need to be fully vaccinated by Jan. 15. But on Jan. 12 evening Canada Border Services Agency spokeswoman Rebecca Purdy told The Canadian Press that Canadian big-riggers will not have to quarantine if they are unvaccinated or have received only one dose. The news came as a surprise to Canadian Trucking Alliance president Stephen Laskowski, who says industry representatives met with government officials as recently as midday Jan. 12 and were told the mandate was still on track for Jan. 15. Trade associations on both sides of the border had been pushing for a delay to the restriction, which they say would put additional strain on supply chains amid the latest COVID-19 surge and severe worker shortages. …