Study of the Pathogenesis of Olfactory Disorders in COVID-19

Study Overview
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Brief Summary
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This study is a case-control study to characterize the molecular and cellular anomalies of the olfactory epithelium of COVID-19 patients with isolated anosmia, by comparison with the olfactory epithelium of non-infected subjects.

Detailed Description
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Olfactory and taste dysfunctions are common and early onset in COVID-19, especially in pauci symptomatic patients, and may be the main clinical manifestations of the infection. Olfactory dysfunction could result from infection of the olfactory system by SARS-CoV-2 or from inflammation induced by the virus. While the recent development of COVID-19 pulmonary lesion research has revealed a viral, inflammatory and vascular origin, factors that cause olfactory disorders in COVID-19 are just beginning. Acute anosmia observed in some patients with COVID-19 could result from: the direct infection of olfactory sensory neurons or neural stem cells of the olfactory mucosa, an underlying inflammation of the olfactory mucosa, leading to possible neurodegeneration of olfactory sensory neurons, and neural stem cells of the olfactory mucosa, by analogy with the respiratory viruses responsible for chronic rhinosinusitis. It is therefore necessary to conduct a virological, cellular, immunological and inflammatory study of the olfactory epithelium from COVID-19 patients with isolated anosmia to identify the origin of these olfactory disorders. This study is a case-control study to characterize the molecular and cellular anomalies of the olfactory epithelium of COVID-19 patients with isolated anosmia, by comparison with the olfactory epithelium of non-infected subjects. Following measures will be performed at inclusion : Taste and olfactory function evaluation by a self-questionnaire taste and smell survey (TTS) and a visual analogue scale (VAS) Nasal swab sampling for collection of epithelium cells and olfactory mucus.

Official Title
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Study of the Pathogenesis of Olfactory Disorders in COVID-19

Conditions
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Coronavirus Infection, Severe Acute Respiratory Syndrome, Sars-CoV2

Intervention / Treatment
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* Other: Nasal swab
* Other: Taste and olfactory function evaluation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: COVID-19 patients Age > 18 years Subject consulting in the context of the COVID-19 screening care for a suspected SARS-CoV-2 infection Controls Age > 18 years Subject consulting in the ear, nose and throat department with no biologically confirmed COVID-19 or suspected COVID-19 in the past 8 weeks, and no symptoms suggestive of COVID-19 or another respiratory disease and therefore no recent anosmia or ageusia Exclusion Criteria (both COVID-19 patients and controls): Refusal or contraindication to nasal swab Presence of nasal sinus pathology

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| COVID-19 patients<br>Subject consulting in the Lariboisière hospital (Paris) in the context of the COVID-19 screening care for a suspected SARS-CoV-2 infection | Other: Nasal swab<br>* Nasal swab<br>Other: Taste and olfactory function evaluation<br>* Taste and olfactory function evaluation<br>|
| Control subjects<br>Subject consulting in the ear, nose and throat department at the Lariboisière hospital (Paris) with no biologically confirmed COVID-19 or suspected COVID-19 in the past 8 weeks, and no symptoms suggestive of COVID-19 or another respiratory disease and therefore no recent anosmia or ageusia | Other: Nasal swab<br>* Nasal swab<br>Other: Taste and olfactory function evaluation<br>* Taste and olfactory function evaluation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Molecular and cellular defects in olfactory epithelium | Ratio of olfactory sensory cells in the nasal cytological sample | 30 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Biological mechanisms involved in the pathogenesis of the disease | Multiple measurements will be analyzed to characterize the immune and inflamatory status of the olfactory mucosa (presence of infiltrated immune cells, activation state of the immune cells in the epithelium, cytokine and interleukin level) | 30 months | 
| Epidemiological characteristics | Demographic variables (sex, age, blood type), risk factors (tobacco, overweight, diabetes, rhinosinusitis disease, respiratory allergy) | 30 months | 
| Olfactory and taste dysfunction | Self-questionnaire taste and smell survey (TTS) | 30 months | 
| Olfactory and taste dysfunction | Visual analogue scale (VAS) (units from 0 normal perception to 100 no perception) | 30 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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SARS-CoV-2, Sense of smell disorders, Anosmia, Olfaction, Nasal neuroepithelium, Olfactory mucosa