The ability of certain dog breeds to sniff-detect for cancer is generally well known.
Here's a study going on to see if they can do the same thing for coronavirus.
about
the study:
"Eight Labrador retrievers — and their powerful noses — have been enlisted to help. The dogs are the first trainees in a University of Pennsylvania research project to determine whether canines can detect an odor associated with the virus that causes the disease COVID-19."
"Research has found viruses have specific odors."
" ... canines (are) a “new diagnostic tool” that “could revolutionize our response to COVID-19.”
“Each individual dog can screen up to 250 people per hour.”
"If the need is lots of tests, then Penn chemists and physicists might be able to use what they learn from the dogs to create an electronic “nose,” or sensor."Obviously there would be problems with training enough dogs and making them available fast enough, as well as other logistical issues, to make this work in real-world settings, but the concept does sound exciting.
Another tool in the toolbox, if this works out.
https://www.washingtonpost.com/science/2020/04/29/coronavirus-detection-dogs/