Can dogs sniff out Covid-19? A study from Finland shows they can. And that’s right, especially if the infection is caused by the wild-type virus they’re being trained with.
After training four dogs, researchers from the University of Helsinki tested 420 samples for which the RT-PCR reports were already known. They also tested 303 arriving passengers at Helsinki-Vantaa International Airport-Finland.
The study showed an overall accuracy of 92% compared to the RT-PCR tests. “Detector dogs trained with the wild-type SARS-CoV-2 virus were also proficient at identifying other variants, albeit less accurately, revealing their robust distinctiveness,” the study said. The study was recently published in the BMJ Global Health Journal.
The Indian Army has also trained two of its dogs to detect Covid-19 over the past year.
In the first part of the study, which was used for validation, the dogs were able to accurately identify 92% of the samples as either Covid-19 positive or negative. “Failure to identify a COVID-19 positive sample has been linked to SARS-CoV-2 variant status. The dogs reported correctly … only 36% of the alpha variant samples,” the study reads.
As for the real scenario at the airport, the results of the dogs agreed with the RT-PCR report in 296 of the 303 people, which means that the accuracy was 97.7%. The only drawback of the real-life study was that there were very few positive cases – only three out of 303. So that the dogs could sniff out Covid-19 even with such a low prevalence, the dogs also received 115 acquaintances RT-PCR positive samples on Airport. They were able to correctly identify 98.7% of them as positive.
At the time of the study – the real airport study was carried out between September 2020 and April 2021 – variants were just emerging in the country. The study states: “Since no variants emerged in Finland at the time of training, only wild-type samples were used. Many of the conflicting results have been linked to the new variant. In the future, the operational work skills are to be maintained through simultaneous training with patterns of newly emerging virus variants.”