COVID-19 test will no longer serve as a substitute for most people.The policy came into effect on Oct. 30, but the federal government allowed a short transition period for unvaccinated travellers who could board as long as they provided a negative molecular COVID-19 test taken within 72 hours before their trip.The stringent new requirement comes into effect as Canada reacts to the emergence of the new, highly mutated Omicron variant of COVID-19.The discovery of the new variant has prompted border closures and heavier screening in Canada and abroad over fears it could prove more transmissible.