COVID-19 exposure on flights is more common than you think. The US doesn't share details, but Canada does


On the day after Christmas, passengers on a United Airlines flight from Denver to Calgary, Alberta, were potentially exposed to COVID-19.

So were travelers on a Delta Air Lines flight from Detroit to Toronto, an Air Canada flight from Fort Lauderdale, Florida, to Montreal and 11 other international flights to Canada.

The next day, another busy holiday travel day, more of the same: 14 flights to Canada from places including Boston; Chicago; Houston; Cancun, Mexico; and the Dominican Republic, all had at least one passenger on board who tested positive for COVID-19 shortly after the flight.

The flights aren't outliers due to the holiday travel rush.   

Data from Canadian public health authorities show a near daily occurrence of flights where a passenger may have been infected while flying. From the start of the coronavirus pandemic in March through early January, the Public Health Agency of Canada has identified potential exposure on more than 1,600 international flights and more than 1,400 flights within Canada, for a total of more than 3,000 flights, including nearly 200 in the past two weeks alone.

On the list: U.S. carriers American, United, Delta, Alaska and Allegiant. The U.S. cities with the most affected flights on the list: Chicago, Phoenix, a magnet for Canadian visitors, and Denver.

The details aren't buried in some secret database. Canada has been posting public COVID-19 exposure alerts online for flights, trains and cruise ships throughout the pandemic. Flights are listed as soon as authorities receive word of a positive test of a recent traveler, regardless of where and when they might have been infected, factors that are hard to pinpoint in most COVID-19 cases. 

Incidents are posted as little as two days after the flight, so other recent travelers can search to see if someone on their flight tested positive and watch for symptoms. The flights fall off the list after two weeks because of Canada's mandatory 14-day quarantine upon arrival. One major Canadian airline, WestJet, keeps a running list of its affected flights (more than 700 to date) on its website for recent passengers and would-be ticket buyers to see.