Smell DysfunctionCOVID-19NCT07571382
Post-Covid-19 Patients Follow-up Study
A study testing Smell training in people with Smell Dysfunction and Taste Dysfunction, run by University of Oslo at 1 site in Norway.
Trial summary
Taste, smell, trigeminal and salivary function is impacted in post-COVID-19 patients Read more about this study
- Who is it for?
- Ages 18 to 80 yearsHealthy volunteers can take part
- Conditions the study is for
- Smell Dysfunction, Taste Dysfunction, Trigeminal Dysfunction
- What is being tested?
- Smell training
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 176 participants
- Where
- 1 siteNorway
- Study dates
- 1 Apr 2021to 25 Apr 2023
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 80 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- -COVID-19 diagnosis
Who cannot join
- -Not COVID-19 diagnosis
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Occurrence and Clinical Management of Chemosensory, Trigeminal, and Salivary Dysfunctions in Post-COVID-19 Patients
Taste, smell, trigeminal and salivary function is impacted in post-COVID-19 patients
- Being tested
- Smell training
- Keywords
- Smell, Taste, Trigeminus, Salivation
- Medical subject headings
- Olfaction Disorders, Taste Disorders, Anosmia, Sialorrhea
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Smell trainingOther
Smell training
| Study group | Role | What they receive |
|---|---|---|
| Parosmia | Other | Parosmia Receives: Other: Smell training |
What is being measured
The primary outcome is the main question the study is designed to answer.
Smell
Olfactory (smell) function will be evaluated using the Twelve felt-tip Sniffin' Sticks test (Burghart Messtechnik GmbH, Holm, Germany). Participants are categorized into anosmic (score 0-6, no smell), hyposmic (score 7-10, reduced smell), and normosmic (score 11-12, normal smell), according to normative classification.
Measured: two years
Secondary outcomes (3)
Taste
Gustatory (taste) function is assessed using Taste Strips impregnated with solutions of four different taste qualities (sweet, sour, salty, and bitter) in four different concentrations (Burghart Messtechnik GmbH, Holm, Germany). Participants are classified into ageusic (score 0, no taste), hypogeusic (score 1-8, reduced taste) and normogeusic (score 9-16, normal taste) using a normative classification. Participants are considered to have a specific ageusia if they are unable to detect all four different concentrations of a particular tastant.
Measured: 2 years
Dry mouth
Xerostomia (oral dryness) iss categorized according to participants' self-reported perception as either no dry mouth (score 0), or dry mouth (score 1). Participants are asked whether the symptoms of xerostomia started before or after COVID-19 infection and are asked open-ended questions where they could describe their experience of oral dryness. Finally, they are asked to report whether there are food items that they had to refrain from eating because of parosmia, dysgeusia, dysesthesia or xerostomia.
Measured: 2 years
Dysesthesia
Dysesthesia (oral burning sensation) iss categorized as either no dysesthesia (score 0), or dysesthesia (score 1). Participants report how often they experienced dysesthesia (constantly, daily, sometimes, periodically, during meals, in between meals), asked to describe where in the mouth they experienced dysesthesia (whole tongue, anterior tongue, lips, palate, buccal mucosa, other), and identify food items that enhanced the dysesthesia (spicy, sweet, sour, salty, bitter).
Measured: 2 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 May 2026
- Study start1 Apr 2021
- Primary completion25 Apr 2023
- Study completion25 Apr 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Smell DysfunctionStudies of the same condition, open and under way.
- 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
- Screening
- Allocation
- Not applicable
- Intervention model
- Sequential
- Masking
- None (open label)
- Enrolment
- 176 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Oslo
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Per Ole Iversen, MD, University of Oslo
- Investigators
- Per Ole Iversen, PhD, Principal investigator, Per Ole Iversen
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07571382
- Sponsor's protocol ID
- 274615
- Acronym
- COVID-19
- Status last verified
- May 2026
- First submitted
- 27 Apr 2026
- Last updated
- 6 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
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
- Occurrence and Clinical Management of Chemosensory, Trigeminal, and Salivary Dysfunctions in Post-COVID-19 Patients
- ClinicalTrials.gov ID
- NCT07571382
- Acronym / sponsor ID
- COVID-19 / 274615
- Keywords
- Smell, Taste, Trigeminus, Salivation
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 176 participants (actual)
- Lead sponsor
- University of OsloUniversity, hospital or other
- Study start
- 1 Apr 2021 (actual)
- Primary completion
- 25 Apr 2023 (actual)
- Study completion
- 25 Apr 2023 (actual)
- First posted
- 6 May 2026 (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.
Taste, smell, trigeminal and salivary function is impacted in post-COVID-19 patients
Study design
- Primary purpose
- Screening
- Allocation
- Not applicable
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Parosmia | Other | Other: Smell trainingParosmia |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- -COVID-19 diagnosis
Key exclusion criteria (1 listed)
- -Not COVID-19 diagnosis
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 |
|---|---|---|
| Smell trainingSmell training | Other | Parosmia |
Primary outcome
Smell
Time frame: two years
Olfactory (smell) function will be evaluated using the Twelve felt-tip Sniffin' Sticks test (Burghart Messtechnik GmbH, Holm, Germany). Participants are categorized into anosmic (score 0-6, no smell), hyposmic (score 7-10, reduced smell), and normosmic (score 11-12, normal smell), according to normative classification.
3 secondary outcomes
Taste
Time frame: 2 years
Dry mouth
Time frame: 2 years
Dysesthesia
Time frame: 2 years
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 May 2026.
- Individual participant dataSharing planned: Undecided
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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. This study is not recruiting at the moment.
Per Ole Iversen, PhD principal investigator
Per Ole Iversen
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Smell training in people with Smell Dysfunction and Taste Dysfunction, run by University of Oslo at 1 site in Norway.
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 1 inclusion and 1 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: finished, 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 1 site in Norway. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Smell (time frame: two years). 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.