People who are infected with the SARS-CoV-2 virus have a distinct odour that can be detected by trained dogs with a high degree of accuracy, according to new research.
This is the most complete study of its kind to date, combining data collected during the first phase of the dog trial, odour analysis and modelling.
The study, which is not yet peer-reviewed, was led by the London School of Hygiene & Tropical Medicine (LSHTM) collaboratively with the charity Medical Detection Dogs and Durham University.
It was part-funded by the UK’s Department of Health & Social Care, and used over 3,500 odour samples donated by the public and NHS staff.
It showed that COVID-19 infection has a distinct smell, which specially trained dogs can rapidly, non-invasively detect with up to 94.3% sensitivity and up to 92% specificity. The dogs were able to detect odour from individuals who were asymptomatic, as well as those with two different strains, and with both high and low viral loads.
The researchers acknowledge the results were achieved in a trial setting with the dogs trained in a controlled environment, however, they believe they could be replicated in real–world settings.
Accompanying mathematical modelling highlights the potential for dogs to be used at ports-of-entry or other sites, with preparatory work suggesting that two dogs could screen 300 plane passengers in around 30 minutes as part of a ‘Rapid Screen and Test’ strategy. Only individuals who are identified by the dogs would require a PCR test.
Use of the Bio Detection dogs plus a confirmatory PCR test are estimated to detect more than twice as many cases and prevent more onward transmission than isolating symptomatic individuals only.
Professor James Logan, Head of the Department of Disease Control at LSHTM, who led the project, said:
“The results of this study far exceeded my expectations. While the mass rollout of vaccines in the UK is a great success, it will take time to achieve the coverage levels needed for our lives to return to near normal. With the threat of new variants entering the country, the need for testing means we face potential continued disruption for some time to come.
“That’s where these amazing dogs could play a role. Further research is needed to see if the dogs can replicate these results in a real-world setting, but these findings are hugely encouraging. The advantage of using this method is being able to detect COVID-19 with incredible speed and good accuracy among large groups of people, even in asymptomatic cases. This really could help us get back to doing the things we love sooner, safely and with less disruption, such as helping to reduce queuing times at border points or sporting events.
“This study and the exciting potential of using dogs to tackle COVID-19 would not have been possible without the volunteers from the public and NHS, and I want to thank everyone who donated valuable odour samples.”
Dr Claire Guest, Chief Scientific Officer at Medical Detection Dogs, said: “These fantastic results are further evidence that dogs are one of the most reliable biosensors for detecting the odour of human disease. Our robust study shows the huge potential for dogs to help in the fight against COVID-19.
“Knowing that we can harness the amazing power of a dog’s nose to detect COVID-19 quickly and non-invasively gives us hope for a return to a more normal way of life through safer travel and access to public places, so that we can again socialise with family and friends.”
