Sniffer dogs trained using smelly socks worn by people with COVID-19 could soon be used at airports and mass gatherings to pick up the “corona odour” of infected people, British scientists say.
Working in teams of two, the COVID-trained dogs could screen a line of several hundred people coming off a plane within half an hour, for example, and detect those infected with up to 94.3 per cent sensitivity, the scientists said.
Presenting results of an early-stage study, which involved some 3500 odour samples donated in the form of unwashed socks or T-shirts worn by members of the public and health workers, the researchers said the dogs were even able to sniff out asymptomatic or mild COVID-19 cases.
The dogs were also able to detect cases caused by a mutant variant that emerged in the UK late last year.
“Dogs could be a great way to screen a large number of people quickly and prevent COVID-19 from being reintroduced into the UK,” said Durham University’s Steve Lindsay, who worked on the study.
We're so excited that the initial results from our #Covid19 super sniffers are in 🐶
And it shows that Covid has a distinct odour which the dogs can detect with up to 94% accuracy.
— Durham University (@durham_uni) May 24, 2021
The London School of Hygiene AND Tropical Medicine’s James Logan, who led the project, said the major advantage of sniffer dogs over other screening methods such as lateral flow testing is their “incredible speed and good accuracy among large groups of people”.
The research is published online and is yet to be peer reviewed.
It adds to other pilot projects in Finland, Germany, Chile and elsewhere which are trialling COVID-trained sniffer dogs at airports.
The dogs in the UK study were trained over several weeks by being introduced to 200 odour samples from people who had tested positive for COVID-19, as well as 200 control samples from people who tested negative.
The highest performing dogs in the trial detected coronavirus odour in the samples with up to 94.3 per cent sensitivity, meaning a low risk of false negative results. For example, a false negative would be the dogs finding that people do not have COVID-19 when they actually do.
The dogs detected the odour with up to 92 per cent specificity, meaning a low risk of false positive results. In this instance, a false positive would mean that the dogs detect that people have COVID-19 when they actually do not.
This accuracy is higher than recommended by the World Health Organisation for COVID-19 diagnostics, Professor Logan’s team said, with the dogs outperforming lateral flow tests, which have an overall sensitivity of between 58 per cent and 77 per cent.
Independent experts cautioned that the findings would need to be replicated in real-world situations.
“This proof of concept study suggests that trained detection dogs could be used in places like airports, sports stadiums and concert venues,” Lawrence Young, a virologist and professor of molecular oncology at Warwick University, said.
“The big question is will this approach work in the real world on people rather than samples of socks and shirts?”