They are known to be able to sniff out illegal drugs and even cancer, but now a new study suggests sniffer dogs can also detect COVID-19 among airline passengers. Perhaps even more remarkable is the study, conducted by researchers in Finland, also found that once trained, dogs are as acuurate at sniffing out COVID-19 as a PCR nose and throat swab test. "Our preliminary observations suggest that dogs primed with one virus type can in a few hours be retrained to detect its variants," added Anu Kantele, a professor of infectious diseases at the Faculty of Medicine at the University of Helsinki, Finland, and colleagues. For the study, the researchers took four dogs previously trained to detect illegal drugs, dangerous goods and cancers, and trained them to recognise SARS-CoV-2 – the virus that causes COVID-19. To do so, the study team used swab samples from 114 people who had tested positive for the virus on a PCR swab test, including 28 with no symptoms, and from 306 negative tests. Remarkably, the dogs were able to successfully detect 92% of infected people and 91% of uninfected people. The dogs' noses were then put to the test in a live environment at Helsinki-Vantaa International Airport in Finland between September 2020 and April 2021. The dogs correctly identified 296 (99%) of 300 passengers with negative PCR results. Read the full release at BMJ Global Health. *Image: Sniffer dogs at Melbourne Airport doing a demonstration, licensed under the Creative Commons Attribution-Share Alike 2.0 Generic license.