A Nose for COVID: Sniffer Dogs Outperform Antigen Tests
Since the start of the COVID pandemic, dogs have been found to be able to sniff out signs of the virus in infected individuals, with some countries deploying the dogs at border posts to quickly check incoming travellers. Now, a new study published in PLOS One shows that they can be faster than rapid antigen tests, and in some instances even more sensitive than PCR testing.
Applications for medical sniffer dogs have been increasingly studied in recent years, and with the arrival of the COVID pandemic, they provided a quick, efficient way to test for SARS-CoV-2 infection. A number of studies demonstrated their effectiveness, with one study reporting a 94% accuracy. Now, this new study shows that can be as accurate as antigen tests, especially in asymptomatic individuals.
The researchers conducted a prospective cohort study in two community COVID screening centres, with 143 symptomatic and 192 asymptomatic adults. Participants were tested with two nasopharyngeal swabs (NPS), one saliva and one sweat sample. The dog handlers (and the dogs…) were blinded to the individuals’ COVID status. The dogs’ sniff tests were compared to nasopharyngeal RT-PCR as the reference standard, saliva RT-PCR and nasopharyngeal antigen testing.
Overall, 109 of the 335 participants tested positive on nasopharyngeal RT-PCR, 78 symptomatic and 31 asymptomatic. The overall sensitivity of canine detection was 97% and even reached 100% in asymptomatic individuals compared to NPS RT-PCR. The specificity was 91%, reaching 94% for asymptomatic individuals. The sensitivity of canine detection was higher than that of nasopharyngeal antigen testing (97%), but the specificity was lower (90% versus 97%).
The researchers concluded that using dogs’ sense of smell to detect SARS-CoV-2 infection could be a speedy alternative to NPS RT-PCR when rapid testing is necessary when antigenic tests are the standard for mass screening.
