Canine olfactory detection and its relevance for the medical identification of patients with COVID-19.

Introduction: The assessment of Volatile Organic Compounds (VOCs) in exhaled breath or sweat represents a potential non-invasive and rapid diagnostic tool for respiratory diseases.

Objective: To determine if trained dogs can reliably identify the odour associated with COVID19.

Methods: This is a monocentric prospective study carried out in the Emergency Department (ED) of a university hospital fromJulyto November 2021.Axillary sweat samples from all patients were collected bytwo trained health care professionals. The samples were collected in the form of sterile gauze swabs placed under the armpits for at least 4 h for each patient.Then, Tubes wereshiftedto the double-blind dog training centre for VOC detection by two individuals.

Results: Dogs were tested using a total of 129 axillary sweat samples; 69 of the 107 patients who tested positive for COVID-19 based on their odours had a positive PCR/Antigen test and 19 of the 22 patients who were tested negative for COVID-19 by the dogs had a negative PCR test. The sniffer dog infection detection method had a sensitivity of 95.83% and a specificity of 33.33%. The PPV was 64.49% and the NPVwas 86.36%. The measurement of the intensity of the connection between the two variables (disease/sign) was very strong (Q = 0.84). This link is statistically significant (X² = 19.13) with a probability p ≤ 0.001.

Conclusion: Overall, the use of trained detection dogs as a screening method for SARS-CoV-2 is an interesting avenue of research that warrants further exploration and validation.