A French study has already shown that dogs are well aware of people affected by Covid-19. In a new science article published on May 16, 2022 at BMJ Global HealthFinnish researchers and French Loic Desquilbet, from the Department of Biostatistics and Clinical Epidemiology (National Veterinary School of Alfort) have shown that canines can be successfully used at an international airport to fight against the spread of coronavirus.
A robust triple-blind study
People infected with the coronavirus can be asymptomatic but still contagious, so it is necessary to deploy a fast and inexpensive way to detect them, unlike PCR testing. “It is believed that dogs can detect different volatile organic compounds (VOCs) released by metabolic processes in their hosts under different conditions.“, especially during infections, recalls this study. It can be seen if a person is affected by Covid-19, a discovery designed to work in France.
Finnish researchers want to provide new, more robust data to fully establish the olfactory capacities of dogs in the fight against coronavirus pandemic. For this, they conducted a randomized, triple-blind study (the dog handler, the experimenter and the researcher in charge of data processing did not know which sample was positive) and a comprehensive airport test of Helsinki-Vantaa. with four dogs.
The triple-blind protocol included four identical sets (for each animal) of 420 skin samples (rubbed with gauze on the neck, forehead and wrist) from 114 positive and 306 negative individuals (tested). on PCR), which were presented randomly to dogs during seven jobs. sessions. In addition, from the end of September 2020 to the end of April 2021, 303 travelers from Helsinki-Vantaa airport were indirectly “scanned” by dogs. “The study was conducted in a specially designed and constructed cabin at the arrival terminal“. It included three separate sampling rooms and the canines were not in contact with travelers performing a PCR test at the same time.
Dogs were disturbed by the alpha variant
Overall, the diagnostic accuracy of all sniffed samples was 92% for the triple-blind study. Regarding the airport test, the results obtained by PCR and in dogs were the same in 98% of cases. Dogs correctly detected 296 of the 300 negative samples. About seven errors: three positive samples were ignored in the animals. And they also “marked” four samples as really negative.
“The only variable strongly associated with the inability to identify positive Covid-19 samples was the alpha variant. In fact, according to the epidemiological situation in our country, virus variants are only beginning to appear at the end of our validation sample collection period.“, line up the Finnish researchers. The dogs were trained only to identify samples from patients infected with the original virus.
“This observation is remarkable because it proves the strong discriminatory power of dogs. The obvious implication is that the training samples should include all epidemiologically relevant variants. Our preliminary observations suggest that dogs ‘primed’ to a type of virus can within hours be retrained to identify its variants.“, They promised.
They showed that dogs could ultimately be used in both high areas of coronavirus prevalence (e.g. hospitals) and areas of low prevalence (airports, ports).