More than two weeks after Canada implemented a rule that incoming airline passengers must show a negative COVID-19 test result before boarding a plane, the country still appears to be seeing some travel-related cases and the federal government is exploring ways to make it harder to go on trips.
As more transmissible variants of the COVID virus emerge across the globe, experts say tightening the leaks around travel becomes even more important, and that the new testing requirements are not likely to catch all cases.
COVID projections from Caroline Colijn, a mathematician and epidemiologist with Simon Fraser University, show a potentially grim picture for the next few months, with a skyrocketing spring wave fuelled by community spread of a more contagious variant.
Colijn says clamping down on travel is her “top recommendation right now.”
“There’s still a good chance that we can prevent – or at least really delay – large numbers of this high-transmission variant coming into Canada,” she said. “And if we can push that peak out to September, we may be able to avert it if most of us are vaccinated by then.”
Colijn says essential travel needs to be more clearly defined by leaders, and quarantine rules more strongly enforced once people arrive. More stringent restrictions on land border crossings and further limitations on travel within the country will also help, she adds.
In British Columbia, Dr. Bonnie Henry has already highlighted that at least two variants of the deadly virus have appeared in the province. These include a variant linked to the United Kingdom as well as a variant connected to South Africa.
In the case of the U.K. variant, which was found on Vancouver Island, Dr. Henry says it was connected with a resident’s trip to London. The only cases of the U.K. variant in B.C., according to Dr. Henry, have been in connection with this resident’s bubble and health experts believe that it is currently contained.
Dr. Henry said the case of the South African variant found in B.C. has no apparent connection to travel, however, and health experts are investigating further into how the person may have contracted this new strain of the coronavirus.
On a national level, Prime Minister Justin Trudeau is calling on Canadians to cancel all upcoming non-essential trips they may have planned. In addition to cautioning Canadians not to travel, the government is looking at include implementing a mandatory quarantine in hotels for returning travellers.
On Jan. 7, the government implemented a requirement that airline passengers entering Canada or flying domestically from city to city must show proof of a negative PCR test that was taken within 72 hours before their flight.
Colijn and other experts are hopeful this rule is catching a large number of positive COVID cases, but the 72-hour window – necessary to ensure people have enough time to get results back – also allows the virus more chances to wiggle through.
In some cases, very small amounts of the virus, which could grow to infectious levels days later, aren’t picked up in testing. Other cases could contract the virus between taking the test and boarding the plane.
Dr. Christopher Mody, the head of the microbiology, immunology and infectious diseases department at the University of Calgary, says PCR tests offer “a snapshot in time,” meaning the result is only valid on the day the test is taken.
“A positive test means you’re infected, but a negative test doesn’t absolutely exclude infection,” Mody said.
A Government of Canada online database that keeps track of possible exposure on domestic and international flights shows that since Jan. 7, hundreds of planes have had at least one passenger on board who tested positive for the virus days after landing and may have been contagious on their flight.
Dr. Zain Chagla, an associate professor of medicine at McMaster University, says while the negative test requirement is likely helping on a large scale, “it’s gonna miss a few people for sure.”
“Clearly it isn’t a perfect system, but there are also a number of people who have been rejected for flights based on their tests,” he said. “This just isn’t enough to say everyone coming into Canada is completely not infectious at the border.”
Experts continue to emphasize that these new variants of COVID-19 are highly transmissible and constantly mutating.
“We’re in a race to get rid of this virus before it outsmarts us,” said Dr. Srinivas Murthy, an associate professor in the faculty of medicine at UBC.
“It’s absolutely important that these next few weeks are taken as seriously as possible,” added Dr. Murthy.
Although the federal and provincial governments are continuing to research and implement strategies for containing these new variants, British Columbia’s health officials anticipate that the current province-wide safety restrictions on gatherings and events will remain in place as an extra precaution.
Epidemiologists in British Columbia say we likely won’t see a relaxing of restrictions until 70 to 80 per cent of the population is vaccinated.
“It’s very clear from the evidence of what we know right now, it won’t be a long time, a matter of months. Hopefully, the fall is a really good marker when can really start to return back to normal,” said Dr. Kiffer Card, an epidemiologist at the University of Victoria.
The good news is that doctors say the current vaccines work against the new variants, however, health officials are still unsure, however, how long protection from the vaccine lasts.
Widespread vaccination is still several months off and in the interim, experts are saying that testing can only be part of the strategy to contain the spread of new cases though.
The mandatory 14-day quarantine period, which Canada is still implementing, needs to be followed properly.
Mody says people also need to understand that a negative test taken days before flying isn’t a free pass to skip that isolation period.
“We are in a very tenuous time with these variants,” Mody said. “If there is community transmission of the variants, we will be in a very serious situation.”
With files to the Canadian Press.
Graham Cox
