According to this NYTimes article, dogs, in several countries, are being trained to detect Covid. So far, the results are very promising. “The smell is obvious, just like grilled meat for us,”
Paywall for article. What are the dogs actually smelling? The virus itself in the air or something from our body in response to the virus?
Here’s a relevant excerpt:
Sniffer dogs work faster and far more cheaply than polymerase chain reaction, or P.C.R., testing, their proponents say. An intake of air through their sensitive snouts is enough to identify within a second the volatile organic compound or cocktail of compounds that are produced when a person with Covid-19 sheds damaged cells, researchers say.
“P.C.R. tests are not immediate, and there are false negative results, while we know that dogs can detect Covid in its incubation phase,” said Dr. Anne-Lise Chaber, an interdisciplinary health expert at the School of Animal and Veterinary Sciences at the University of Adelaide in Australia who has been working for six months with 15 Covid-sniffing dogs.
Some methods of detection, like temperature screening, can’t identify infected people who have no symptoms. But dogs can, because the infected lungs and trachea produce a trademark scent. And dogs need fewer molecules to nose out Covid than are required for P.C.R. testing, Thai researchers said.
So what we need at the entrances to stores, malls, public buildings of all sorts is two-dog teams. One to sniff and one to bite the unvaxxed carriers the sniffer detects. 
Here’s more detail:
“as a group, the dogs being trained in Thailand — Angel, Bobby, Bravo and three others, Apollo, Tiger and Nasa — accurately detected the virus 96.2 percent of the time in controlled settings, according to university researchers. Studies in Germany and the United Arab Emirates had lower but still impressive results. . . .
The six dogs were assigned six handlers, who exposed them to sweat-stained cotton balls from the socks and armpits of Covid-positive individuals. Researchers say the risks to the dogs are low: The coronavirus is not known to be easily transmissible through perspiration . . . .
Within a couple months of training, at about 600 sniffs per day, the Thai dogs were sitting obediently whenever they sensed the cellular byproducts of Covid-19 on cotton balls, which researchers placed at nose height on a carousel-like contraption.”
And airports!
I can smell people who are going to get a cold, an acrid smell if I am within a foot of them.
It must not be terribly difficult for dogs with their excellent smell system.
What breed are you?
European Mongrel.
Appears to be a Mus Batwieldus to me.
I’ll check my papers.
Yep, European Mongrel. Wanna step out in the alley behind the bar and talk about it?
Never argue with a man carrying a bat at least twice as long as he is. That’s a rule to live by, not get beaten silly by.
I recognize the odor of the flu. I had the flu a lot as a child. One year, as an adult, i got the nasal vaccine for flu and as they squirted it up my nose i thought, “i recognize that stench”.
I was told (i forget where) that before blood tests, doctors used to diagnose mono by the odor of the patient’s breath.
I don’t find it even a little surprising that covid produces an odor that’s recognizable to a dog.
But i read all the time about dogs being trained to recognize cancer, or whatever, and it never goes anywhere. I suspect there’s no money in trained dogs. Maybe this will be different. Maybe there’s enough money in keeping covid out of airports that this will catch on. But they use some fancy “sniffing machine” to test for explosives in airports, rather than dogs. I bet that this won’t go anywhere, either.