Unvaccinated travellers over the age of 12 barred from planes and trains as of today

Unvaccinated travellers over the age of 12 won't be able to board a plane or passenger train in Canada beginning today, and a negative 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 the coronavirus.

The discovery of the new variant has prompted border closures and heavier screening in Canada and abroad over fears it could prove more transmissible.

The risk related to the Omicron variant is very high, according to the World Health Organization, but there is still a lot public health officials and scientists do not know about it.

While anyone coming into Canada or boarding a plane or train inside the country must be vaccinated, there are currently no quarantine measures in place except for people who have recently transited through southern Africa.

While many airlines have so far been doing random spot checks to ensure travellers are vaccinated, Air Canada and West Jet have confirmed they will ask for proof from everyone boarding in Canada as of today.

Other measures, like masks and health screenings, will still be mandatory.

"If you indicate to your airline or railway company that you're eligible to board, but fail to provide proof of vaccination or valid COVID-19 test result, you won't be allowed to travel and could face penalties or fines," the government's website states.

The rule does not apply to commuter trains.

The government has issued warnings on social media that even Canadians and permanent residents abroad will not be able to return home and skip quarantine without a full slate of approved vaccines.

There are some exceptions, including valid medical exemptions, travel to remote communities only accessible by plane, and those transiting through Canada en route to another destination.

Most people who qualify for an exemption will need a recent COVID-19 test.

The vaccine mandate was met with a positive reaction from Canada's airline industry when it was first announced in October, though some companies worried about making the necessary preparations in time.