SARS-COV-2 VIRUS INFECTED PATIENT IDENTIFICATION THROUGH CANINE OLFACTIVE DETECTION ON AXILLARY SWEAT SAMPLES

Grandjean, D.; Gallet, C.; Lecoq-Julien, C.; Sarkis, R.; Muzzin, Q.; Roger, V.; Roisse, D.; Dirn, N.; Levert, C.; Breton, E.; Galtat, A.; Forget, A.; Charreaudeau, S.; Gasmi, F.; Jean-Baptiste, C.; Petitjean, S.; Hamon, K.; Duquesne, J.-M.; Coudert, C.; Tourtier, J.-P.; Billy, C.; Wurtz, J.-M.; Chauvin, A.; Eyer, X.; Ziani, S.; Prevel, L.; Cherubini, I.; Khelili-Houas, E.; Hausfater, P.; Devillier, P.; Desquilbet, L.

Facing the COVID-19 pandemic, testing individuals in order to promptly isolate positive people is one of the key actions. One approach to rapid testing might be to consider the olfactory capacities of trained detection dogs in order to develop a non-invasive, rapid and cheap mass detection approach, through the Volatile Organic Compounds (VOCs) signature of SARS-CoV-2 infection. The goal of this study is to determine the individual values of sensitivity and specificity of trained dogs when performing olfactory detection of COVID-19 on axillary sweat samples. A group of 7 dogs was tested on a total of 218 samples (62 positive and 156 negative), completely unknown to the dogs, following a randomised and double-blinded protocol carried out on olfaction cone line-ups. To ensure a wide olfactory range as close as possible to operational conditions, the samples were retrieved from 13 different sites. Sensitivities vary from 87 to 94p100 for 6 dogs, and are above 90p100 for 3 of them. Only one dog, whose sensitivity was 60p100, was not selected to continue the study and enter the operational stage. Sensitivity results vary from 78 to 92p100, with 6 dogs over 85p100 and 4 over 90p100. Thanks to these results, a virtual approach of Positive and Negative Predilection Values (PPV and NPV) was designed, based on an almost perfect diagnostic tool as reference and for increasing prevalence values of SARS-CoV-2 infection. The studies to come on olfactory detection of COVID-19 by dogs will still face several challenges, but the accumulation of positive and encouraging results suggest that it may play an important part in mass COVID-19 pre-testing situations.