A sensitivity of 97%
The researchers who conducted the study tested the ability of sniffer dogs to detect people carrying Covid-19 in real conditions. To do this, they trained four dogs previously used in the search for drugs, dangerous goods or even cancer to detect the Sars-Cov-2 virus. The dogs were then tested at the entrance to Helsinki-Vantaa International Airport between September 2020 and April 2021. The canines had to use their scent on 303 passengers, with more than positive results. They, in fact, correctly identified 296 negative tests out of 300 and identified 3 positive cases as negative, a success rate of 99%.
To refine the results of their study and correct a possible statistical bias that could have been due to the low prevalence of the virus among passengers going to the airport, the researchers added 155 additional people who had previously been tested positive for Covid-19 by nasopharyngeal PCR tests. The dogs still detected 99% of the positive cases, which allowed the scientists to affirm that if these additional people or samples had been part of the study in real conditions, the sensitivity of the detection of Covid-19 by the dogs would have been 97%, while the specificity would have been 99%. This performance is much higher than that of nasopharyngeal PCR tests, which is on average only 92%, according to the High Authority for He alth (HAS).
Dogs, future allies against epidemics?
Dogs were already used in the detection of certain diseases such as cancer.They were even used in Marseille to detect Covid in May 2021, with an efficiency rate then estimated at 92%. But now, scientists and dog handlers see the results of these studies as a new opportunity. Dogs could, indeed, be used in the future to detect infectious diseases in people who do not show symptoms. Trained doggies have an undeniable advantage over other screening techniques. “The advantage of the dog is the speed of execution, that is to say that he will be able to go up a line of 40 people in three minutes”, explained to Europe 1 Eric, sailor-firefighter from Marseille having participated in the training of dogs for the detection of Covid in 2021.
Dogs are therefore more effective than PCR tests in screening for Covid in public places, both in terms of reliability and sensitivity and speed of execution. These assets could in the future be exploited in the detection of possible future viruses or bacteria that could cause the pandemics of tomorrow.