Inclusion Criteria:  Adult subjects (≥ 18 years) testing positive for COVID-19 (rapid antigenic test) with self-reported nasal obstruction & rhinorrhea ≤48 hours Subjects with mild to moderate COVID-19 symptoms Willing to have regular nasopharyngeal swabs as per protocol Subjects agreeing to follow the study requirements during the whole study period Subject affiliated to social security Subject able to understand verbal and written local language and in capacity to fill-in questionnaire by himself  Exclusion Criteria:  Age over 65 years Subjects requiring hospitalization Subjects with severe COVID-19 symptoms Inability or unwillingness to perform saline irrigations subjects who have performed nasal wash in the previous week including the day of inclusion Requirement to take regular medications administered by nasal route (topical treatment such as corticosteroids, antihistaminics, vasoconstrictors, inhalation) Subjects intending to undergo nasal surgery during the study period or who underwent nasal surgery in the 3 previous months. Pregnancy or breastfeeding Hypertension Cardiovascular pathologies: history of stroke, history of coronary artery disease, history of cardiac surgery, NYHA stage III or IV heart failure; Diabetes Smokers Asthma (requiring treatment) Chronic pulmonary / respiratory pathology (cystic fibrosis, obstructive pulmonary disease (COPD), pulmonary fibrosis, etc.) Chronic renal disease (eg: renal failure) Obesity (BMI ≥ 30) Progressive cancer under treatment Chronic haematological pathology Chronic liver disease (eg: cirrhosis) HIV infection / other immune deficiency (congenital or acquired immunosuppression) Has received an organ or bone marrow transplant Chronic neurological abnormality / disease Immunosuppression Subject who received at least one dose of any COVID-19 vaccine Taking part in another interventional clinical trial or in the exclusion period to another study Those who do not have access to email/internet Not capable of giving informed consent Hypersensitivity or known allergy to any component of the product Patient with a member of his household already included in the study Patient living in another department than the recruiting laboratory