A collaborative study between Durham University, London School of Hygiene & Tropical Medicine, and a group called Medical Detection Dogs might improve the quality of air travel. The researchers have trained dogs to detect positive COVID-19 cases, and the study could have far-reaching implications for frequent fliers and beyond. 

Dogs have an acute sense of smell. Humans have approximately 6 million olfactory receptors in their noses, while dogs can possess up to 300 million olfactory receptors. Dogs also use a part of their brain for smelling that is proportionally 40 times larger than the same part in humans. The discerning noses of disease-sniffing dogs can identify cancer, narcolepsy, and malaria. In a global pandemic, it makes sense to lean on dogs’ superior sense of smell to aid in COVID-19 detection. 


What the Study Found

In this Phase 1 Trial, dogs sniffed out COVID-19-19 on masks and other articles of clothing. The dogs were away from identifying false-positives, so they can correctly identify both positive and negative cases. Training took about 6 to 8 weeks. The dogs in the study range in age from 4 to 6 years old, and their breeds are Cocker Spaniel, Labrador, or Golden Retriever. 

COVID-19 carries a specific odor to these dogs’ expert noses. Scientists are still trying to figure out the exact chemical makeup that produces COVID-19’s identifiable smell. The dogs had an 82% to 94% sensitivity rate in their ability to detect the presence of COVID-19, while the specificity rate ranges from 76% to 92%. This specificity measurement indicates whether the dogs could tell if a person did not have COVID-19. The dogs are able to identify COVID-19-positivity even in asymptomatic cases. 

The study’s authors still point to the PCR test as the top COVID-19 detector, but COVID-detecting dogs can be useful in crowded places. Using dogs to screen for COVID-19 at airport terminals could result in a 91% detection rate, and reduce rates of transmission. When a COVID-detecting dog identifies a traveller as COVID-positive, the next courses of action would be quarantine and a PCR test. 

COVID-19-detecting dogs could also act as a visual warning to travelers who might consider traveling while infected. This method of detection could also prevent the need for travelers to quarantine. 

However, spatial conditions could reduce detection rates. The dogs’ ability to identify COVID-19 might suffer depending on how crowded an indoor space is, or if outdoor spaces have increased airflow. Additionally, COVID-detecting dogs have different specificity rates and cannot guarantee universal rates of detection. 


What About the Pups?

This COVID-19 detection method does pose a risk to the dogs themselves. Dogs can be infected with SARS-COV-2, which is the virus that causes COVID-19. The illness presents both asymptomatically and to varying levels of infection, just like its symptomatic range in humans. 

The Phase 1 Trial findings should ultimately be considered tentative as the research is still awaiting peer-review. The Phase 2 Trial will test dogs’ abilities to identify COVID-19 in infected people, not just masks and articles of clothing. As results from the Phase 2 Trial become publicly available and applicable, COVID-detecting dogs could change the landscape of airport viral transmission for the better.