Canine Sniff and RT-PCR? wild-type virus that trained them

Can dogs smell Covid-19? A study from Finland shows that they can. And it is mainly when the infection is caused by the wild-type virus that trained them.

After training four dogs, researchers from the University of Helsinki tested 420 samples whose RT-PCR reports were known. They also tried 303 passengers arriving at Helsinki-Vantaa International Airport.

This study demonstrated an overall accuracy of 92% compared to the RT-PCR test. "Scent dogs trained with the wild-type SARS-CoV-2 virus also mastered the identification of other variants, although less accurately, revealing their strong distinctiveness," the study said. 

In the first part of the study used for validation, dogs correctly identified 92% of the samples as positive or negative for Covid-19. "Failure to identify a COVID-19 positive sample is related to the status of the SARS-CoV-2 variant. However, according to the study, dogs correctly identified "only 36% of the alpha sample."

As for the actual scenario at the airport, the results of dogs agree with the RT-PCR report of as many as 296 out of 303 people, which means the accuracy is 97.7%. The only downside to the real-life study was very few positive cases - only three out of 303. To ensure dogs could smell Covid-19 even at low levels, dogs also received 115 known RT-PCR - positive samples. At the airport. They were able to identify 98.7% of them as positive correctly.