An interventional study of Clinical examination and Blood collection in SARS-CoV-2 Acute Respiratory Disease, sponsored by Institut Pasteur. Completed at 1 site in France. Open to participants aged 18 Years to 55 Years. Per ClinicalTrials.gov, last updated 2025-05-14.
Sponsored by Institut Pasteur · Not applicable, Interventional, and Basic science
The COVID-19 pandemic is a novel medical challenge, particularly because of the systemic nature of this disease. Indeed, COVID-19 affects several organs and systems at once. The brain is affected in several ways: direct infection of nerve cells by SARS-CoV-2, inflammation of the central nervous system, severe systemic inflammation damaging nerve cells, global cerebral ischaemia related to respiratory failure, thromboembolic events related to increased intravascular coagulation and severe psychological stress. As a result, COVID-19 sometimes manifests as neurological and neuropsychiatric symptoms such as dizziness, sleep disturbances, cognitive deficits, delirium, or severe depression.
Sudden loss of smell is a common symptom associated with COVID-19 and SARS-CoV-2 infection of neurons in the olfactory system has been reported in both hamsters and humans. The vast majority of COVID-19 patients recover their olfactory function within a few weeks. However, a significant minority of infected individuals (1 in 5 cases) still suffers from olfactory disorders (anosmia, hyposmia and/or parosmia) several months after the primary infection. These olfactory disorders are frequently associated with depressive behaviour and cognitive complaints. In PET scans, it is even possible to correlate this cognitive dysfunction with hypometabolism of certain brain regions, including the olfactory gyrus.
This project proposes, during one year, to evaluate and follow the evolution of the olfactory capacities of patients suffering from persistent smell disorder since one year (+/- 4 months) following COVID-19. The issue is to study the link between viral persistence in the olfactory sensory organ, chronic inflammation, and central damage to the olfactory system. The follow-up of the evolution of olfactory and neurocognitive capacities, in an integrative way by means of molecular, physiological and behavioural approaches, will inform us on the specificities of "COVID-long" and on the level of peripheral and/or central damage of the olfactory system.
Prospective monocentric descriptive study. Evaluation of COVID-19 patients with persistent loss of smell during 2 visits at 1 year intervals (V1 and V2).
V1 :The following examinations will be carried out specifically for the research.
V2 :
All examinations performed at V1 will be repeated at V2.
If the following examinations are not carried out during care within 3 weeks of V2, they will be carried out as part of the research during this V2 visit.
The following explorations will be carried out:
In addition, MRI data from clinical care will be collected.
617 studies on the registry are indexed under Respiratory Tract Diseases; 111 are open to participants now.
This study's enrollment of 30 is below the median of 80 across 381 interventional studies indexed under Respiratory Tract Diseases.
Browse Respiratory Tract Diseases studies →Institut Pasteur is the lead sponsor of 96 studies on the registry; 40 are open to participants now.
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Exclusion Criteria:
Adult subjects up to 55 years of age with persistent olfaction disorder after a symptomatic episode of COVID-19.
Other: Clinical examination · Other: Blood collection · Other: Olfactory evoked potentials · Other: Brushing of olfactory slits · Other: Neurological examination and neuropsychological assessment · Other: Nasal endoscopy · Other: Assessment of olfactory and taste functions
The investigator will conduct a clinical examination to rule out other causes of olfactory impairment independent of COVID-19. The investigator will also collect the following information: socio-demographic data (age, sex, blood type, weight, height, etc.), history of olfaction disorder symptoms, past or current treatments received and tobacco/alcohol consumption.
12ml-blood sample
Olfactory evoked potentials will be recorded during olfactory tests.
collection of olfactory slits cells.
* MOCA, BREF * CVLT * WAIS IV, MEM III * Right-side and left-side empan, Trail Making Test A and B (TMT), verbal fluency tests, PASAT, Attention Assessment Test * Benton's Line Judgement, VOSP * Assessment of psychological status, fatigue and screening for psychiatric comorbidities: depression \& anxiety scales (HAD scale, mADRS depression scale, STAI anxiety scale), Fatigue Severity Scale.
Nasal endoscopy
* scales: VAS and TSS * Sniffin Stick test
Measurement of olfactory responses by PEO recording and by calculating the TDI score of the Sniffin'stick tests.
To characterise the evolution of the olfactory capacities of patients suffering from persistent odour disorders following SARS-CoV-2 infection over the course of a year.
Time frame: 24 months
Measurement of olfactory perception threshold, olfactory discrimination capacity and odour identification.
Describe the olfactory performance
Time frame: 24 months
To characterise the persistence of SARS-CoV-2 in the olfactory epithelium.
Characterisation of the presence of SARS-CoV-2 by PCR in the olfactory mucosa.
Time frame: 24 months
To characterise any damage to the olfactory nerve
Mapping analysis of the olfactory nerve of COVID-19 patients by MRI tractography technique.
Time frame: 24 months
To identify the presence of inflammatory markers in patients.
Measurement of cellular and inflammatory markers in the olfactory mucosa.
Time frame: 24 months
Detection and measurement of markers of neurological disorders in the blood.
To identify the neurological damage in patients.
Time frame: 24 months
Measurement of patients' cognitive performance by neuropsychological assessment (standardised tests).
To identify possible cognitive abnormalities in these patients with prolonged loss of smell.
Time frame: 24 months
Plan to share: No
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This study is completed, as verified in May 2025. You cannot join it, but the record below documents what was studied.
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