A group in France, led by veterinary scientist Dominique Grandjean at the National Veterinary School of Alfort near Paris, posted its work3 on the preprint server bioRxiv in June. The researchers, who included Sarkis, trained 8 dogs to detect COVID-19 in 198 sweat samples, around half of which were from people with the disease. When these were hidden in a row of negative samples, the dogs identified the positive samples 83–100% of the time. The paper does not say how well the dogs identified negative test results. The research is now under review at a journal, but Grandjean says the process has not been easy. “To publish papers on detection dogs is very difficult because most reviewers do not know anything about working dogs,” he says.
The data in that study look promising, says Fyodor Urnov, a gene-editing scientist who is working on COVID testing at the University of California, Berkeley. But he would like to see larger data sets on how well dogs identify positive and negative samples. He also notes that there is variation in how well individual dogs perform. In Grandjean’s study, for example, 2 dogs identified 68 out of 68 positive samples, whereas one missed 10 out of 57 cases.
Groups need to boost their sample sizes before the wider scientific community can evaluate how useful the dogs might be, agrees James Logan, an infectious-disease researcher at the London School of Hygiene & Tropical Medicine who is training and studying COVID-19 dogs, including Storm, Maple and Asher. “It’s important not to go out too early with grand claims and small data sets,” he says.
Can dogs smell COVID? Here’s what the science says
Canines seem to detect coronavirus infections with remarkable accuracy, but researchers say large-scale studies are needed before the approach is scaled up.https://t.co/0XgMmjdzRf pic.twitter.com/td34nAxJKW
— Rahim Azizian (@AzizianRahim) November 23, 2020