Publish date: 26 May 2021

People infected with coronavirus have a distinct odour that can be detected by trained dogs with a high degree of accuracy, according to new research involving UCLH.

The findings mean trained ‘bio detection’ dogs could be effective as a new rapid, non-invasive screening tool at ports of entry.

The study, which is not yet peer-reviewed, was led by the London School of Hygiene & Tropical Medicine (LSHTM) with the charity Medical Detection Dogs and Durham University. The UCLH site lead was Dr Catherine Houlihan.

The study used over 3,500 odour samples donated by the public and NHS staff, including staff at UCLH. Detection dogs were trained to detect the presence of coronavirus by rewarding them for indicating a positive sample, or for ignoring a negative sample.

Six dogs then took part in a ‘double-blind’ trial where the dog, technician and dog trainer were not aware of which samples were positive or negative.

The study found that Covid-19 infection has a distinct smell, which specially trained dogs can rapidly, non-invasively detect with up to 94% accuracy. 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.

Modelling accompanying the research suggests dogs could 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.

Researchers now hope to proceed to the next phase of the trial, which will see the dogs detecting Covid-19 on real people in real world settings.

Dr Houlihan said: “Our findings suggest specially trained dogs could be incredibly helpful at identifying quickly who may have coronavirus and require a further test. The dogs could play a vital role at ports of entry – especially in a context where we need to be continually vigilant about the threat of new variants emerging – and the study team and I look forward to next trialling the dogs in real world settings.”