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.
Findings “give hope”
The findings of the UK study, which has not yet been peer-reviewed, are based on six dogs who tested more than 3,500 odour samples donated by the public and NHS staff.
The dogs, Asher, Kyp, Lexia, Tala, Millie and Marlow, from the charity Medical Detection Dogs, took part in the double-blind trial.
This means that 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.
Researchers have said the findings are very promising and give “real hope” for detecting different variants of coronavirus in the future.
Professor James Logan, head of the department of disease control at London School of Hygiene and Tropical Medicine (LSHTM), who led the project, said: “What was great was the dogs that have been trained on the original variant transferred to the new (Kent) variant.
“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.”
Detecting Covid in real-world settings
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 already 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.
Professor 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.”