The voluntary canine tests will deliver results within 10 seconds and require less than a minute of travelers’ time, said Anna Hielm-Björkman, a researcher at the University of Helsinki who is using the trial to gather data.

Researchers in other countries, including the United States and the United Arab Emirates, are studying canine coronavirus tests. But the Finnish trial is among the largest in scale and farthest along.

In Dubai, health officials this summer began using dogs to analyze sweat samples from randomly selected air travelers, with more than 90 percent accuracy, according to initial results.

Changes in health can affect the way people smell, researchers say. Dogs have long been valued for their ability to sniff for drugs and bombs, and have also proved able to detect cancers, infections and other health problems.