The spread of the new SARS-CoV-2 virus has led to a pandemic. Described for the first time in China at the end of 2019, it causes Covid-19 disease. Its characteristics in terms of contagiousness and lethality have led countries to adapt their screening and care strategies.

Early and accurate identification of people infected with SARs-CoV-2 is an essential measure to confront Covid-19 pandemic. A key aspect of Covid-19 is that diagnostic tests must be able to detect the virus in asymptomatic, pre-symptomatic and symptomatic patients.

Changes in human odor, as symptoms of specific diseases, have been observed. Dogs have already been used to detect breast or lung cancer, diabetes, epilepsy or kidney disease with some success There is currently a growing body of research and previous work, though preliminary, indicating the possibility that dogs identify persons infected with Sars-Cov-2 compared to healthy persons.

The purpose of this study is to determine whether trained detection dogs are able to identify asymptomatic patients infected by Sars-Cov-2.

The investigators aim to validate the possibility to identify / discriminate patients with Covid-19 according to their odor by a proof of concept (with specificity and sensitivity of the detection test), i.e. new non-invasive screening method using dogs odor detection capabilities.

Inclusion Criteria:

• Aged ≥ 18 years
• Having given free and informed written consent
• Being affiliated to the center national security system social
• Patients infected by SARS-COV-2 with positive RT PCR on nasopharyngeal swab and without symptoms (fever, cough, anosmia, diarrhea) will be included in "experimental" Group 1.
• Patients infected by SARS COV 2 with positive RT PCR on nasopharyngeal swab and presenting at least one symptom will be included in Group 2 "control".
• Participants not infected by SARS-COV-2 with negative RT PCR on nasopharyngeal sample and showing no symptoms on Day 0 and Day 7 will be included in Group 3 "healthy controls".

Exclusion Criteria:

- Patient whose life expectancy is less than 3 months