Can dogs detect COVID-19?

German Shepherd sniffer dog

Testing for COVID-19 is now more important than ever to avoid a second wave, sweeping local regions and whole countries in and out of lockdown. However, it has been widely acknowledged that mass testing regimes will play a key role in minimising the impact of the disease. As testing is proving challenging in some environments and even in some countries, are there other reliable methods which could prevent COVID-19 from spreading? Some dog behavioural experts believe the key could be in the form of our canine friends.


How can dogs act against COVID-19?

Since the global outbreak, researchers have been accessing the accuracy of dogs trained to detect people infected with COVID-19, especially those who are asymptomatic and aren't displaying symptoms.

Canine olfactive (sense of smell) detection has proven its efficacy in numerous situations (explosives, drugs, bank notes…) including for early diagnosis of human diseases: various cancers, alert of diabetic or epileptic people in immediate alarm of crisis.
— (Pirrone and Albertini, 2017)*

If proven effective and accurate, sniffer dogs could be invaluable towards the fight against the spread of COVID-19.

What are dogs trained to detect?

Sniffer dogs detecting any scent will often have to pass four stages of training before they can begin working in a live environment.

stage 1 red circle illustration

Stage one

The scent will be placed in a tube or on a piece of cloth. The dog will then play with it until associating the object with the odour. 

stage 2 red circle illustration

Stage two

Whilst the dog is watching, the object is hidden in an easily accessible area before being encouraged to find it. The object will then be hidden in more difficult areas to access. Positive reinforcement is used to encourage the dog to find the object.

stage 3 red circle illustration

Stage three

The object covered in the desired scent is now hidden in an inaccessible place, without the dog watching where it is hidden. They will then be given a command to find the object and trained to signal when they can small the desired odour.

stage 4 red circle illustration

Stage four

The object is no longer used and the dog must now learn to search for the odour associated with the object.

Around the world, there are a number of different researchers looking into the possibility of training dogs to detect COVID-19. The Nosais Project in France at the Alfort Veterinary School is being led by Professor Dominique Grandjean and Clothilde Lecoq, who are looking into the effectiveness of training dogs commonly used to detect other substances.

The first phase of the program is to train dogs to sniff human sweat samples and see if they can differentiate the sweat odour of COVID-19 [positive] patients compared to that of COVID-19 [negative] persons.
— (Grandjean et al., 2020)**

So far, results from their initial research have been promising, concluding there is high evidence that dogs can detect a person infected by COVID-19.

Sniffer dogs and handlers in an airport

What traits are common in sniffer dogs?

Sniffer dogs have been used for decades and the ideal traits in these dogs are playfulness and dynamism with plenty of energy, as it can be hard work to carry out multiple searches each day. Also, a dogs sense of smell is incredibly powerful, and much better than that of a human, making it possible for them to detect COVID-19 through odours.

The 18 dogs participating in the study each had an existing skill, such as detecting explosives, banknotes and disaster zones as well as diseases like colon cancer. However, dogs that have previously detected drugs were excluded from the study.

We did not decide to work with drug detection dogs as there is always a possibility that COVID-19 positive or negative people use prohibited substances that would let catabolites be excreted by the axillary sweat.
— (Grandjean et al., 2020)**

Belgian Shepherds, German Shepherds and Labradors are commonly used as sniffer dogs. However, Cocker Spaniels and Yorkshire Terriers are beginning to be used more with one reason being they can be transported in the arms of their handler easily if it's necessary to navigate difficult terrain.

Can dogs suffer from coronavirus symptoms?

The current spread of COVID-19 is a result of human to human transmission. According to the World Organisation for Animal Health (OIE) to date, there is no evidence to suggest that companion animals are playing a role in the spread of COVID-19. 

Find our latest guidance on the coronavirus pandemic and how this could affect your pet here.

How will these dogs be used within society?

In many countries worldwide, diagnostic tests are lacking in order to set up a mass detection of COVID-19 contaminant people, we think it is important to explore the possibility of introducing dog olfactive detection as a rapid, reliable and cheap “tool” to either pre-test willing people or be a fast checking option in certain circumstances.
— (Grandjean et al., 2020)**

If dogs are able to detect COVID-19 accurately, they will be helpful in airports when identifying whether it is safe for a visitor to enter a country. Emirates Airline and Lebanon have been deploying dogs in airports for several weeks now, with Finland and France (in the Corsica region) also starting to carry out such tests. 

As trials continue, the initial research appears to be producing positive results. The hope is that these dogs can begin wider testing on the general public to protect everyone and perform a key role in reducing the spread of the virus.


*Pirrone, F. and Albertini, M., 2017. Olfactory detection of cancer by trained sniffer dogs: A systematic review of the literature. Journal of Veterinary Behavior, 19, pp.105-117.

**Grandjean et al., 2020. Detection dogs as a help in the detection of COVID-19 Can the dog alert on COVID-19 positive persons by sniffing axillary sweat samples ? Proof-of-concept study.