OTTAWA—Canada’s tight labor market is forcing many companies to offer regular COVID-19 testing over vaccine mandates, while others are reversing previously announced inoculation requirements. Canadian Prime Minister Justin Trudeau’s government adopted one of the strictest inoculation policies in the world for civil servants and has already put more than 1,000 workers on unpaid leave, with thousands more at risk. Airlines, police forces, school boards, and even Canada’s Big Five banks have also pledged strict mandatory vaccine policies. But following through has proven less straightforward, especially as employers grapple with staffing shortages and workers demand exemptions. Job vacancies in Canada have doubled so far this year, official data shows, and vaccine mandates can make filling those jobs harder, potentially putting upward pressure on wages. That could fuel inflation, already running at a near two-decade high. “It’s already difficult to find staff, let alone putting in a vaccine mandate. You’d cut out potentially …