Public health officials aren't doing enough to reach out to people from different provinces who may have been exposed to COVID-19 on flights, often stopping contact tracing at their own borders, an epidemiologist warns.
"Canada has a system of contact tracing on the ground, but as soon as it's wheels up and they start pushing a little beverage cart around, then that system stops," said Amir Attaran, a professor of both law and epidemiology at the University of Ottawa.
Part of the problem appears to be that each province or territory is responsible for tracking cases within its borders, but flights often span multiple jurisdictions. It appears as though the federal government isn't tracing cross-border cases, instead relying on provinces and territories to notify one another — sometimes indirectly through their websites.
Even then, it can take time for that information to reach passengers who were potentially exposed to the virus, if it ever does.
In Manitoba, for example, over the past six weeks, public health officials announced six domestic flights carrying symptomatic Manitobans and three international flights carrying two Manitobans who tested positive for COVID-19.
That information was made public between one week and 17 days after the flights landed.
"That's useless," Attaran said.
"Those passengers [who were infected by a person on the flight] have had time to fall ill, have had time to transmit it to somebody else and that somebody else has had time to transmit it to somebody else."
Canada's chief medical officer, Theresa Tam, says there have been no reported cases of transmissions in the air in Canada, but says there is an opportunity to investigate the risks fully.
"I do think that more effort in looking at how we best get that contact information can at least help us evaluate that data better moving forward," Tam told a news conference last week.
Gabor Lukacs, an air passenger rights advocate, says Canadians are being put at risk on flights and different levels of government should do more to ensure information is passed along to the public.
"We live in a world where real-time passage of information can potentially save lives," he said.
"Whatever happens in one province affects other provinces as well."
The information is made public quickly after it comes to light, but people sometimes don't get tested for the coronavirus until they show symptoms or days later, said a spokesperson from Manitoba Health, Seniors and Active Living.
Attaran says that isn't the only problem. The Public Health Agency of Canada (PHAC) still communicates with provinces and territories via fax machine and the process is slow.
"The sharing that takes place ... when it takes place, is typically weeks after the case and it reaches the federal government third-hand, fourth-hand even," he said.
Data sharing slow, incomplete
PHAC says it relies on provinces and territories to pass along when a person in their jurisdiction who has tested positive for the coronavirus was on a flight while infectious, which is then posted online.
But PHAC acknowledges its flight list isn't exhaustive.
In Manitoba, public health officials don't directly inform officials in other provinces if residents have been exposed to the virus on a flight, according to a provincial spokesperson.
The information is posted on the province's website and passed on to the media and to the federal government, but those flights don't always end up on the PHAC dashboard.
That's what most jurisdictions in Canada do, and that's a national guideline, the spokesperson said.
It is also how the province informs people they may have been exposed to the virus, rather than following up with people individually.
"There is no direct evidence at this time that contacting individual air travellers has made it possible to find cases earlier," a provincial spokesperson said.
The spokesperson also said Manitoba doesn't hear from other jurisdictions if cases are confirmed in other provinces connected to a sick Manitoban passenger.
'Challenge' to get data from airlines: Tam
Attaran says contact tracing means following up with everyone who is possibly exposed to the virus.
"This is what you do on the ground. Why would you do something different in the air?"
It isn't that easy, according to Tam.
She says getting complete information from airlines to do contact tracing has "always been a challenge."
"Depending on the airlines, it's missing all sorts of information so you can't reach the persons in certain seats, if they stayed in the right seats, that is," she said at a news conference on Aug. 4.
Health officials in B.C. have echoed these statements about flight manifests in recent days, calling on flights to provide in-depth contact information to assist with contact tracing.
When asked about how many close contacts resulted from symptomatic Manitobans on flights over the past few weeks, the province refused to provide more information, citing the need to protect the individuals from "stigma and shaming."
Meanwhile, the B.C. Centre for Disease Control wouldn't say whether there are any cases locally stemming from a Manitoba passenger on board a flight to Vancouver, and Toronto Public Health told CBC News they aren't tracing any cases related to the same passenger who travelled through the city.
Alberta Health Services wouldn't say if it's doing any contact tracing related to a Manitoban who flew to Calgary and back.
Federal public health officials post information about flights, trains and buses where passengers could have potentially been exposed to the virus for about two weeks, but not all of the flights that Manitoba has made public made it on the list.
"If a province identifies that a person who has tested positive had been in another province within a time period that is relevant to disease transmission, there are existing protocols for them to contact their colleagues in the other province to assist in the contact tracing," a spokesperson from the federal government said.
"All jurisdictions work together to do their best to ensure all contacts of a case have been identified and are aware of the next steps they need to take to protect their health and the health of those around them."
Nobody should be flying: Attaran
Attaran has a word of caution for Canadians considering flying during the pandemic.
"Nobody, nobody, nobody, nobody should be flying if the authorities have made a decision that contact tracing does not happen in the air," he said.
On top of that, he said, there's the inability to physically distance on flights.
Air Canada and WestJet began selling tickets for adjacent seats as of July 1, after blocking access to those seats for the past few months to allow passengers to maintain some distance from each other.
Still, Attaran says, there's "no way" he'll be flying any time soon.