Covid19DysOSMICNCT06482138
Dysfunction of Olfaction After COVID-19 Infection: Morphological and Histomolecular Investigation
A study testing Biopsy and Cytobrush in people with Covid19 and Olfactory Dysfunction, run by Universitaire Ziekenhuizen KU Leuven at 7 sites in 3 countries.
Trial summary
Investigation of the mechanisms of persistent SARS-CoV-2 associated olfactory dysfunction (OD) in patients with well-documented olfactory function. The investigators plan to collect olfactory cleft biopsies and cytobrushes in COVID-19 patients and controls. Read more about this study
- Who is it for?
- Ages 18 to 70 years
- Conditions the study is for
- Covid19, Olfactory Dysfunction
- What is being tested?
- Biopsy and Cytobrush
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 240 participants
- Where
- 7 sitesin 3 countries
- Study dates
- 24 Jan 2024to 31 Dec 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Olfactory Dysfunction group: Presence of evident OD (Parosmia, Threshold-Discrimination-Identification (TDI)-score ≤24, Subjective abnormal quantitative olfactory function; measured by a visual analogue score (VAS) of smell impairment ≥5/10
- Control group: No OD (TDI-score \>30.5.)
Who cannot join
- Presence of concomitant nasal mucosal pathology that might affect olfactory function or bias the study investigations
- Use of anticoagulation therapy
- Allergy to local anesthetics
Trial locations and contacts
7 sites in 3 countries. Contact the study team or a site near you to ask about taking part.
7 sites in 3 countries
Belgium3 sites, 3 recruiting
- Recruiting
AZ Sint-Jan Brugge
Bruges, West-Vlaanderen, 8000
Kato Speleman, 0477910294, kato.speleman@azsintjan.be
- Recruiting
Cliniques Universitaires Saint-Luc
Brussels, Brussels Capital, 1000
Caroline Huart, 0477910294, caroline.huart@saintluc.uclouvain.be
- Recruiting
UZ/KU Leuven
Leuven, Vlaams-Brabant, 3000
Laura van Gerven, +3216336342, laura.vangerven@uzleuven.be
Laura van Gerven
Germany2 sites, 1 recruiting
- Recruiting
University Hospital Carl Gustav Carus
Dresden, Dresden, 01307
Thomas Hummel, +493514582264, thomas.hummel@tu-dresden.de
Thomas Hummel
- Active, not recruiting
Max Planck Research Unit for Neurogenetics
Frankfurt am Main, Frankfurt, 60438
Switzerland2 sites, 2 recruiting
- Recruiting
Hôpitaux Universitaires de Genève
Geneva, Canton of Geneva, 1211
Basile Landis, +41 223728268, Basile.Landis@hcuge.ch
Basile Landis
- Recruiting
University of Zurich and University Hospital Zurich
Zurich, Canton of Zurich, 8091
Michael Soyka, +41 432538819, michael.soyka@usz.ch
Michael Soyka
About this study
Official title: Dysfunction of Olfaction After SARS-CoV-2 Infection: Morphological and Histomolecular Investigation of Olfactory Cleft Biopsies and Cytobrushes
Investigation of the mechanisms of persistent SARS-CoV-2 associated olfactory dysfunction (OD) in patients with well-documented olfactory function. The investigators plan to collect olfactory cleft biopsies and cytobrushes in COVID-19 patients and controls.
Read the detailed description
An explorative prospective clinical study using human body materials of living post-COVID-19 patients with and without OD, to study the mechanisms of persisting olfactory dysfunction. Patients consult ENT specialist for medical purposes and undergo standard-of-care diagnostics and management. The collected tissues from the olfactory cleft mucosa will be analyzed using single cell RNA sequencing and RNAscope combined with immunohistochemistry.
- Conditions
- Covid19, Olfactory Dysfunction
- Being tested
- Biopsy and Cytobrush
- Keywords
- Olfactory Dysfunction, COVID-19, SARS-CoV-2, Anosmia, Hyposmia
- Medical subject headings
- COVID-19, Anosmia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Biopsy and CytobrushProcedure or surgery
Collection of olfactory cleft biopsies and cytobrushes
| Study group | Role | What they receive |
|---|---|---|
| Control | Other | Biopsy and cytobrush during a scheduled structural intervention in general anesthesia Receives: Procedure: Biopsy and Cytobrush |
| Olfactory Dysfunction | Other | Biopsy and cytobrush during consultation in local anesthesia Receives: Procedure: Biopsy and Cytobrush |
What is being measured
The primary outcome is the main question the study is designed to answer.
Analysis of olfactory cleft biopsies
Morphological and histomolecular differences between OD and control patients
- Evaluating tissue pathology:
- Metaplasia
- hypertrophy
- aberrant scar formation
- apoptosis
- presence of inflammatory cells [H\&E, CD68 and CD3 stainings, RNAscope]
- Presence of SARS-CoV-2 RNA
- Percentage of OSNs versus sustentacular cells; maturation of OSNs
Measured: From enrollment of 1 patient until analyzed, 1 month
Analysis of olfactory cytobrushes
Morphological and histomolecular differences between OD and control patients
- Evaluating tissue pathology:
- Metaplasia
- hypertrophy
- aberrant scar formation
- apoptosis
- presence of inflammatory cells [H\&E, CD68 and CD3 stainings, RNAscope]
- Presence of SARS-CoV-2 RNA
- In the olfactory epithelium: percentage of OSNs versus sustentacular cells; maturation of OSNs
Measured: From enrollment of 1 patient until analyzed, 1 month
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Jul 2024
- Study start24 Jan 2024
- Primary completion31 Dec 2026 (estimated)
- Study completion31 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Covid19Studies of the same condition, open and under way.
- More trials run by Universitaire Ziekenhuizen KU LeuvenThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 240 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Universitaire Ziekenhuizen KU Leuven
- Sponsor type
- University, hospital or other
- Collaborators
- University Hospital, Geneva, Max Planck Research Unit for Neurogenetics, University Hospital Carl Gustav Carus, University of Zurich
- Responsible party
- Sponsor
- Investigators
- Laura van Gerven, Principal investigator, UZ/KU Leuven
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06482138
- Sponsor's protocol ID
- S67380
- Acronym
- DysOSMIC
- Status last verified
- Apr 2026
- First submitted
- 19 Feb 2024
- Last updated
- 6 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 6 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Dysfunction of Olfaction After SARS-CoV-2 Infection: Morphological and Histomolecular Investigation of Olfactory Cleft Biopsies and Cytobrushes
- ClinicalTrials.gov ID
- NCT06482138
- Acronym / sponsor ID
- DysOSMIC / S67380
- Conditions
- Covid19, Olfactory Dysfunction
- Keywords
- Olfactory Dysfunction, COVID-19, SARS-CoV-2, Anosmia, Hyposmia
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 240 participants (estimated)
- Lead sponsor
- Universitaire Ziekenhuizen KU LeuvenUniversity, hospital or other
- Collaborators
- University Hospital, Geneva, Max Planck Research Unit for Neurogenetics, University Hospital Carl Gustav Carus, University of Zurich
- Study start
- 24 Jan 2024 (actual)
- Primary completion
- 31 Dec 2026 (estimated)
- Study completion
- 31 Dec 2026 (estimated)
- First posted
- 1 Jul 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Investigation of the mechanisms of persistent SARS-CoV-2 associated olfactory dysfunction (OD) in patients with well-documented olfactory function. The investigators plan to collect olfactory cleft biopsies and cytobrushes in COVID-19 patients and controls.
Detailed description
An explorative prospective clinical study using human body materials of living post-COVID-19 patients with and without OD, to study the mechanisms of persisting olfactory dysfunction. Patients consult ENT specialist for medical purposes and undergo standard-of-care diagnostics and management. The collected tissues from the olfactory cleft mucosa will be analyzed using single cell RNA sequencing and RNAscope combined with immunohistochemistry.
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Control | Other | Procedure: Biopsy and CytobrushBiopsy and cytobrush during a scheduled structural intervention in general anesthesia |
| Olfactory Dysfunction | Other | Procedure: Biopsy and CytobrushBiopsy and cytobrush during consultation in local anesthesia |
Who may qualify
- Ages
- 18 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Olfactory Dysfunction group: Presence of evident OD (Parosmia, Threshold-Discrimination-Identification (TDI)-score ≤24, Subjective abnormal quantitative olfactory function; measured by a visual analogue score (VAS) of smell impairment ≥5/10
- Control group: No OD (TDI-score \>30.5.)
Key exclusion criteria (3 listed)
- Presence of concomitant nasal mucosal pathology that might affect olfactory function or bias the study investigations
- Use of anticoagulation therapy
- Allergy to local anesthetics
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Biopsy and CytobrushCollection of olfactory cleft biopsies and cytobrushes | Procedure or surgery | Control, Olfactory Dysfunction |
Primary outcome
Analysis of olfactory cleft biopsies
Time frame: From enrollment of 1 patient until analyzed, 1 month
Morphological and histomolecular differences between OD and control patients * Evaluating tissue pathology: * Metaplasia * hypertrophy * aberrant scar formation * apoptosis * presence of inflammatory cells [H\&E, CD68 and CD3 stainings, RNAscope] * Presence of SARS-CoV-2 RNA * Percentage of OSNs versus sustentacular cells; maturation of OSNs
Analysis of olfactory cytobrushes
Time frame: From enrollment of 1 patient until analyzed, 1 month
Morphological and histomolecular differences between OD and control patients * Evaluating tissue pathology: * Metaplasia * hypertrophy * aberrant scar formation * apoptosis * presence of inflammatory cells [H\&E, CD68 and CD3 stainings, RNAscope] * Presence of SARS-CoV-2 RNA * In the olfactory epithelium: percentage of OSNs versus sustentacular cells; maturation of OSNs
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 May 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Laura van Gerven principal investigator
UZ/KU Leuven
7 sites in 3 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Biopsy and Cytobrush in people with Covid19 and Olfactory Dysfunction, run by Universitaire Ziekenhuizen KU Leuven at 7 sites in 3 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 6 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 7 sites in Belgium, Germany, Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Laura van Gerven (+3216336342, laura.vangerven@uzleuven.be), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Analysis of olfactory cleft biopsies (time frame: From enrollment of 1 patient until analyzed, 1 month). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 May 2026.