Prospective, randomized, controlled, multicenter, parallel clinical trial to assess the efficacy of seawater nasal wash to relieve COVID-19 and URTIs nasal symptoms and reduce intranasal viral load in subjects with mild to moderate COVID-19 disease and URTIs.

SARS-CoV-2 coronavirus enters into the human body mainly through the angiotensin converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2) nasal epithelial cells. Like many other airborne viral diseases, penetration into the upper respiratory tract (URT) is the first step of the infection. Once SARS-CoV-2 enters the host via the respiratory tract, airway and alveolar epithelial cells, vascular endothelial cells and alveolar macrophages are among the first targets of viral entry. Several studies have reported that the viral loads in the upper respiratory tract (URT) peak at the time of, or early after, onset of symptoms. Higher virus load in upper respiratory tract (URT) also induces a higher overall SARS-CoV-2 household secondary attack rate.

Nasal saline irrigations are frequently prescribed for both prevention and treatment of upper respiratory tract infections (URTIs). Nasal wash provides mechanical cleansing of mucus, crust, cell debris and various air contaminants including pathogens (virus and bacteria). It enhances mucociliary clearance and reduces the mucus contact time of airborne elements. The effectiveness of nasal lavage has been shown to reduce the duration of infectious episodes and relieve symptoms of upper respiratory tract infections (URTIs) caused by various respiratory viruses including coronaviruses. Preliminary data showed that daily nasal wash can significantly reduce symptom duration in subjects with mild and moderate forms of COVID-19.

The sponsor hypothesized that the daily use of seawater nasal wash in subjects with mild to moderate forms of COVID-19 or URTIs:

• Would relieve nasal symptoms caused by SARS-CoV-2 and URTIs virus, including nasal obstruction and rhinorrhea.
• Would reduce the intranasal viral load by mechanical evacuation of nasal secretions containing the viruses, and by reducing the contact time between the viruses and the nasal mucosa.

The main objective of this study is to evaluate the effectiveness of Physiomer®, an undiluted isotonic seawater nasal spray, on reducing the duration of nasal symptoms (nasal obstruction or rhinorrhea) in subjects with mild to moderate COVID-19 and URTIs.

The study will take place in France among adults subjects who developed nasal obstruction and rhinorrhea no more than 48 hours before study inclusion. Subjects will be randomized into one of two study groups: control group or nasal wash group. Subjects in the nasal wash group will be asked to perform daily nasal wash for a 3 weeks period with Physiomer®, a 100% seawater isotonic nasal spray. Subjects in both groups will complete daily online questionnaires for a 3 weeks period. In order to follow the evolution of intra-nasal viral load, 4 naso-pharyngeal swabs will be collected at home by a nurse.

Inclusion Criteria:

• Adult subjects (≥ 18 years) with self-reported nasal obstruction and/or rhinorrhea ≤48 hours due to COVID-19 or URTIs
• 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
• Cardiovascular pathologies: history of stroke, history of coronary artery disease, history of cardiac surgery, NYHA stage III or IV heart failure;
• 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 having his 2nd injection of COVID-19 vaccine scheduled during the 3 weeks of study follow-up
• 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 region than the recruiting laboratory