Canadian health officials say passenger exposure to COVID-19 on flights occurs regularly, with 200 known exposures in the last two weeks, USA Today reports, adding the US does not release exposure data on flights.

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.

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.