Dysfunction of Olfaction After COVID-19 Infection: Morphological and Histomolecular Investigation (DysOSMIC)

April 30, 2026 updated by: Universitaire Ziekenhuizen KU Leuven

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.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

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 Type

Interventional

Enrollment (Estimated)

240

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Belgium
    • Brussels Capital
      • Brussels, Brussels Capital, Belgium, 1000
    • Vlaams-Brabant
      • Leuven, Vlaams-Brabant, Belgium, 3000
        • Recruiting
        • UZ/KU Leuven
        • Contact:
        • Principal Investigator:
          • Laura van Gerven
        • Sub-Investigator:
          • Marnick Clijsters
        • Sub-Investigator:
          • Sabrina Bischoff
    • West-Vlaanderen
      • Bruges, West-Vlaanderen, Belgium, 8000
  • Germany
    • Dresden
      • Dresden, Dresden, Germany, 01307
        • Recruiting
        • University Hospital Carl Gustav Carus
        • Contact:
        • Principal Investigator:
          • Thomas Hummel
    • Frankfurt
      • Frankfurt am Main, Frankfurt, Germany, 60438
        • Active, not recruiting
        • Max Planck Research Unit for Neurogenetics
  • Switzerland
    • Canton of Geneva
      • Geneva, Canton of Geneva, Switzerland, 1211
        • Recruiting
        • Hôpitaux Universitaires de Genève
        • Contact:
        • Principal Investigator:
          • Basile Landis
        • Sub-Investigator:
          • Julien Hsieh
    • Canton of Zurich
      • Zurich, Canton of Zurich, Switzerland, 8091
        • Recruiting
        • University of Zurich and University Hospital Zurich
        • Contact:
        • Principal Investigator:
          • Michael Soyka

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • 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.)

Exclusion Criteria:

  • Presence of concomitant nasal mucosal pathology that might affect olfactory function or bias the study investigations
  • Use of anticoagulation therapy
  • Allergy to local anesthetics

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Control
Biopsy and cytobrush during a scheduled structural intervention in general anesthesia
Procedure: Biopsy and Cytobrush
Collection of olfactory cleft biopsies and cytobrushes
Other: Olfactory Dysfunction
Biopsy and cytobrush during consultation in local anesthesia
Procedure: Biopsy and Cytobrush
Collection of olfactory cleft biopsies and cytobrushes

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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
From enrollment of 1 patient until analyzed, 1 month
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
From enrollment of 1 patient until analyzed, 1 month

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Universitaire Ziekenhuizen KU Leuven

Collaborators

University of Zurich
University Hospital, Geneva
University Hospital Carl Gustav Carus
Max Planck Research Unit for Neurogenetics

Investigators

  • Principal Investigator: Laura van Gerven, UZ/KU Leuven

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 24, 2024

Primary Completion (Estimated)

December 31, 2026

Study Completion (Estimated)

December 31, 2026

Study Registration Dates

First Submitted

February 19, 2024

First Submitted That Met QC Criteria

June 28, 2024

First Posted (Actual)

July 1, 2024

Study Record Updates

Last Update Posted (Actual)

May 6, 2026

Last Update Submitted That Met QC Criteria

April 30, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • S67380

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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