PCR tests that use swabs to detect cases of covid-19 may be less effective at identifying the coronavirus in a person than dogs trained for this purpose, a study published by the scientific journal Plos One.

According to the study, canines are able to detect Covid-19 better than PCR tests, both in symptomatic and asymptomatic people.

"The dog doesn't lie," Dominique Grandjean, a professor at France's Alfort National Veterinary School and author of the study, told Science News, noting that some errors can occur with PCR tests.

The study included 335 participants from Covid-19 testing centers in Paris. Of the participants, 109 were identified as positive, including 31 who were asymptomatic.

The authors of the French study said that soon more dogs could be used to detect Covid-19 at mass testing sites, including airports. If this materialises, France could join the United Arab Emirates and Finland, which already use the method to identify Covid-19 in these places.