The sense of smell in dogs is unparalleled, which is even more sensitive than the most advanced man-made instrument. They possess up to 300 million olfactory receptors in their noses, compared to about six million in humans.
Once trained, medical detection dogs are able to smell metabolic changes to people’s breath and sweat. Their sense of smell can even be more accurate than conventional COVID-19 tests.
The United Arab Emirates has 38 sniffer dogs working at its airports that can identify infected persons at a 98.2% success rate. Police trained the dogs to recognize the scent of COVID-19 using samples of sweat from people with confirmed infections, collected by holding a swab in an armpit for a few minutes.
Several other countries including Finland, the United States and France have also been running their own dog training and trials of canine detection of COVID-19.