Intended for healthcare professionals


Sixty seconds on . . . covid-19 sniffer dogs

BMJ 2020; 370 doi: (Published 25 September 2020) Cite this as: BMJ 2020;370:m3758

Read our latest coverage of the coronavirus outbreak

  1. Zosia Kmietowicz
  1. The BMJ

What’s this, another shaggy dog story?

Not at all. Canine scent detectors have been working at Helsinki-Vantaa Airport since 22 September in a pilot study to see if they can speed up the detection of SARs-CoV-2 in the arrivals lounge.

Are we talking about new test labs?

Possibly, although dog breed is less important than a love of sniffing, according to trainers from Wise Nose (, the research group at the University of Helsinki that’s leading the project. Most of the 10 dogs being trained to detect the virus have done sniffing work before, identifying cancers, moulds, and bed bugs. Kössi, an eight year old greyhound mix at work at the airport learnt to identify the scent of SARs-CoV-2 in just seven minutes.

Just how effective arethey?

A dog only needs 10-100 molecules of SARS-CoV-2 to identify the virus, whereas standard polymerase chain reaction test equipment requires 18 million. And preliminary tests, conducted by researchers at the veterinary faculty of the University of Helsinki, show that dogs can smell the virus with almost 100% certainty. They can also identify people with the virus before symptoms appear.

Is Finland leading the way?

Ulla Lettijeff, the director of Helsinki-Vantaa Airport, believes so. “We are among the pioneers. As far as we know no other airport has attempted to use canine scent detection on such a large scale. This might be an additional step forward on the way to beating covid-19,” she said.

Dogs to the rescue

Absolutely. Susanna Paavilainen, Wise Nose chief executive, has ambitions to hound out the current testing service from the airport. “We’re working with Finnish customs to prepare for a potential scenario where dog sniffing takes charge of the operation,” she said, though that will require a change in the law.

So, a warm welcome awaits from man’s best friend?

Unfortunately, you won’t get anywhere near the dogs. People taking the test swipe their skin with a wipe which is then placed in a cup and presented to the dog. Those who test positive will be referred to health services.

Is NHS test and trace barking up the wrong tree?

I couldn’t possibly comment. Deenan Pillay, a professor of virology at University College London, said that, like a contact tracing app, dogs could potentially be useful, but were not a “magic bullet” that could replace “a well functioning public health approach.”