Canada could consider scrapping the pricey COVID-19 PCR test for travellers

As the U.S. reopens its land border, some experts say the Canadian government should consider scrapping its costly COVID-19 PCR test requirement for fully vaccinated travellers — particularly for short cross-border trips.

Instead, they suggest Ottawa could look at using the less expensive, faster and more convenient antigen tests, which are used to screen travellers in the U.S., but are also less reliable.

"Wouldn't it make more sense to have [an antigen test] done at the border rapidly? You can get one done in 15 minutes or even faster … rather than a 72 hour-old [PCR] test that's sometimes logistically difficult [and] expensive to get," said Amesh Adalja, an infectious disease physician and a senior scholar at the Johns Hopkins Center for Health Security in Baltimore.

"From the scientific standpoint, the antigen tests make more sense," he said, pointing to the fact antigen tests are done much closer to the time of the crossing. "So I think that the U.S. policy is actually a better one."

Currently, recreational travellers entering Canada must show proof of a negative PCR test taken within 72 hours of their departing flight or planned arrival at the border. But those tests can be expensive, running up to $300, and can take up to 24 hours — or longer — for travellers to get their results.

It's particularly prohibitive for families, as the molecular tests are required for everyone over the age of five. That means for a family of four, it can add $1,000 to the cost of a trip.

Some countries, like the U.S., only require a rapid antigen test, which costs as little as $20 and provides results in as little as 15 minutes.

But antigen tests aren't as sensitive as molecular PCR tests (or polymerase chain reaction tests), meaning antigen tests can miss low levels of the virus.

"It leads to a high false-negative because your body has to generate enough of the virus for it to show us a positive result," said Warren Chan, a professor of biomedical engineering at the University of Toronto

"In a PCR test, the level at which you can detect is significantly much lower. So if you've been infected with a [low level] of the virus, PCR tests would be able to pick it up, but antigen tests cannot."

 Dr. Fatima Kakkar, a Montreal-based pediatric infectious disease specialist, agreed that the PCR test is the "gold standard" of testing for COVID-19.

If PCR tests are a 100, she said, an antigen test would be about an 80 or 90, meaning that they could be missing up to 20 per cent of people with COVID-19.

That means it was certainly reasonable for Canada to require the PCR test before vaccines became widespread, said Kakkar.

"Now that we're all vaccinated, the question is: Is it OK to take that risk?," she said of the calls to switch to antigen testing. "And I think it's reasonable to ask the question right now."