UMBERTO BAACHI THE rollout of the first batches of COVID-19 vaccines in Britain and the United States has reignited a debate around the possible use of digital health passports to ease the lockdowns that are crippling the global economy. Proponents say identifying people who are immune to the novel coronavirus or at lower risk of spreading it could help open up travel and other services. But, critics have raised concerns over privacy, health and discrimination. As more technology firms develop digital certificates that can be accessed on smartphones by employers, airlines and others here is all you need to know…