Early data suggest a federal pre-flight testing requirement has not stopped COVID-infected passengers from flying into Canada

A new pre-flight testing requirement has not stopped the flow of passengers infected with COVID from entering Canada, according to an analysis by Western Aviation News.

The federal government brought in new rules January 7. They require most people flying to Canada on an international flight to get a COVID-19 test within 72 hours of boarding, with limited exceptions.

Within days, Westjet and Transat reported denying boarding to hundreds of passengers. That happened either because their test was done outside the legal window, or the passenger didn’t get a specific kind of test. Passengers have to get a PRC test, considered the gold standard.

However, a review of publicly-available data suggests the measure has done little to reduce the number of warnings issued in the past 10 days.

The Public Health Agency of Canada issues warnings when people may have been exposed to COVID-19 on a flight. The data are kept active for two weeks. That’s the quarantine period for international arrivals.

An upward tick

Between January 1 and 6, the eve of the new rules’ implementation, officials issued warnings for 65 international flights arriving in Canada. From the 7th to the 12th, six days after implementation, they issued warnings for 83 flights. Another four flights have been added to the list since then. Warnings are based on reports from provincial and international health authorities. The data are variable and seem to lag by a few days. New flights are constantly added and altered, even several days after arrival.

For comparison’s sake, PHAC has published 83 domestic flights with potential exposures between the New Year and January 6. Between the 7th and the 12th, PHAC says 61 flights had an infected person on board.

Last week, Vancouver International released preliminary results from a pre-flight testing program. They show no COVID infections among 200 Westjet passengers departing on domestic flights.

“The interim results indicate that a rapid antigen testing approach is feasible for use in departing air travellers,” the airport said, “especially for domestic or short international flights.”

COVID transmission on flights is rare. “The risk of contracting COVID-19 on board a flight is very low,” says the International Air Transport Association. “There have been millions of flights since the start of the COVID-19 outbreak resulting in less than 50 confirmed cases of transmission in-flight.”

One of those cases includes an 18-hour Emirates flight from Dubai to Auckland. Researchers traced the pattern of COVID transmission from two people to as many as five other passengers seated nearby. The initial couple was tested before they boarded their flight from Switzerland to Dubai and on to Auckland. Their test was negative within 72 hours of departure.

“That 3 passengers had positive test results on day 3 of their 14-day quarantine period indicates some of the complexities of determining the value of predeparture testing, including the modality and timing of any such testing,” the researchers concluded.

Of 451,000 COVID cases in Canada with a known source of transmission, 11,000 were traced to travel or contact with a traveller. In March, Ottawa closed Canada’s borders and barred most non-citizens or permanent residents from entering the country.