Sniffer dogs accurately scent out Covid from smelly socks

Great Horwood's amazing Medical Detection Dogs prove their skill by sniffing socks, masks and T-shirts in university trial

Wednesday, 26th May 2021, 5:03 pm
The six amazing Medical Detection Dogs that took part in the study

Specially trained dogs are able to sniff out Covid-19 with up to 94 per cent accuracy, new research suggests.

A coronavirus infection has a distinct smell, meaning canines are able to detect samples from people who have been infected but are asymptomatic, as well as those with low viral loads.

Dogs were also able to identify infections caused by the coronavirus strain that was dominant in the UK last year, along with the Kent variant which was detected later in the year.

Medical Detection Dog Asher

The findings of the UK study, which has not yet been peer-reviewed, are based on six dogs from the Great Horwood-based charity Medical Detection Dogs, who tested more than 3,500 odour samples on masks, socks and T-shirts donated by the public and NHS staff.

The dogs - cocker spaniel Asher, Labradors Lexie, Tala and Marlow, golden retriever Millie and Labrador x retriever Kyp - took part in the double-blind trial - meaning neither the research team nor the dogs knew which of the odour samples came from people infected with coronavirus, and which were Covid-free.

The study, which was part funded by the Department of Health and Social Care (DHSC), showed that the trained dogs were able to correctly identify positive Covid-infected samples with up to 94.3 per cent specificity.

They were also able to correctly identify negative Covid samples with up to 92 per cent specificity.

Medical Detection Dog Millie at work

Prof James Logan, head of the Department of Disease Control at London School of Hygiene and Tropical Medicine (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.”

Prof Logan added: “What was great was the dogs that have been trained on the original variant transferred to the new (Kent) variant.

Medical Detection Dogs founder Claire Guest

“They could detect the new variant without any additional training. So this gives us real hope and really suggests that dogs are able to detect different variants of Covid.”

Dr Claire Guest, founder and chief scientific officer of 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.”

Researchers said the next phase of the trial will test whether the “super sniffers” are able to detect coronavirus on real people, in real-world settings, such as airports and sporting events.

Preliminary analysis using mathematical modellings suggests that two dogs would be able to screen 300 plane passengers within 30 minutes.

Scientists said that, using a rapid screen and test strategy, people who are identified by the dogs as having coronavirus would then require a PCR test to confirm diagnosis.

They believe that a combination of specially trained dogs, coupled with a confirmatory PCR test, could help to detect twice as many cases and reduce onward transmission, compared to isolating symptomatic individuals only, or testing people with a lateral flow test and a PCR test.

Prof Steve Lindsay, from the Department of Biosciences at Durham University, said: “This is a very exciting result showing that there is a distinct smell associated with Covid-19 and, more importantly, that trained dogs can detect this with a high degree of accuracy.

“Dogs could be a great way to screen a large number of people quickly and preventing Covid-19 from being reintroduced into the UK.

“Trained dogs could potentially act as a fast screening tool for travellers, with those identified as infective confirmed with a lab test.

“This could make testing faster and save money.”