MONTREAL -- In the last week and a half, three Air Transat flights from Port-au-Prince, Haiti, landed in Montreal with many COVID-19-infected passengers on board.

While they weren't subject to Canada's new negative-test requirement at the time, Health Canada data still raises questions about whether international travel can be made COVID-safe with or without the tests.

In its published data tracking COVID-19 cases on flights, Health Canada doesn’t include the exact number of infected people on each flight. But enough people tested positive on those three flights from Haiti, upon arriving in Canada, that the federal agency flagged all rows on all the flights as “affected” by the virus.

The three flights are identified by the codes TS663, referring to a flight on January 10, TS665, which flew on January 13, and TS663, on January 17.

Since January 7, the federal government has required everyone flying into Canada to provide proof of a recent negative test for the virus, taken within 72 hours of their scheduled departure time. Without that proof, passengers are prohibited from boarding their flights.

However, Haiti was among the countries temporarily exempted from this rule until Jan. 20 due to a lack of test availability. Instead, passengers from Haiti until Jan. 20 had to get a COVID-19 test at a federal quarantine facility upon arriving in Canada.

Passengers from Haiti “were strongly encouraged to perform a test before their flight but could not be denied boarding if they had not been able to,” said Air Transat spokesperson Marie-Christine Pouliot in an email.

“As of today, this exemption is no longer in effect.”

MANY TRAVELLERS STILL ARRIVING WITH VIRUS, DESPITE TEST RULE

According to Air Transat, since the Jan. 7 testing rule was implemented, 472 passengers have been denied boarding on the company's flights because they did not have the negative COVID-19 result.

But even among flights from countries where the test is required, a significant number have had passengers test positive for the virus after arriving in Canada.

The exposure data published on Health Canada’s website shows that 140 international flights have landed in Canada since Jan. 7 where passengers on a portion of the plane were exposed to COVID-19 due to at least one confirmed case of the virus on board the flight. 

A COVID-19 infection takes several days to show up in most people -- after what's known as the incubation period -- so if people are tested very soon after their infection, the test will show up as negative, even if the person becomes contagious very shortly afterwards.

According to the federal website, a row of a plane is considered "affected" if it's within three rows behind or in front of a row where a seated person is confirmed to have COVID-19 during a period when they may have been contagious.

It adds that "all rows" on the flight may be considered affected "if multiple cases are confirmed and spread out across the aircraft."

The growing list of affected flights is raising concern amongst provincial and federal leaders and health officials.

On Tuesday, and again on Thursday, Quebec Premier Francois Legault said he's asking the Trudeau government to ban all international travel departing from Canada that is not essential, including trips to all-inclusive resorts.

He also called on the federal government to enforce the post-travel quarantine requirement more strictly and said the province is willing to take extra measures on its own if Ottawa doesn’t act.

Legault said he's concerned about the risk of international travellers bringing more cases of the COVID-19 variants, which are more transmissible, into Quebec. Right now, health authorities say Quebec has seen no new cases of the variant since the first five cases, which were all within the same family.

In a separate press conference Tuesday, Prime Minister Justin Trudeau urged people not to travel for non-essential reasons and asked people who have booked trips to cancel them.

Correction:

An earlier version of this story stated that 7,472 Air Transat travellers had been denied boarding since Jan. 7 after failing to provide a negative test result. In fact, only 472 have been denied boarding. CTV regrets the error.