NCT04495816.

Study name	Randomised control trial of omega‐3 fatty acid supplementation for the treatment of COVID‐19 related olfactory dysfunction
Methods	Parallel‐group randomised controlled trial
Participants	Adults with self‐reported new onset olfactory dysfunction and COVID‐19 infection Inclusion criteria: Adults (18 years of age or older) with self‐reported new onset olfactory dysfunction Positive COVID‐19 diagnosis Exclusion criteria: Patients who are less than 18 years of age Patients without a positive COVID‐19 PCR results, obtained through nasopharyngeal swab Patients with COVID‐19 diagnosis, but without self‐reported anosmia Patients with severe COVID‐19 disease, as defined by the Mount Sinai Health System (requiring high flow nasal cannula, nonrebreather, CPAP/BiPAP, mechanical ventilation, pressor medication or evidence of end‐organ damage) Pre‐existing self‐reported olfactory dysfunction History of chronic nasal/sinus infections (rhinosinusitis) or history of endoscopic sinus surgery Use of nasal steroid sprays or irrigations for any reason Prisoners of the state Presence of psychiatric or developmental conditions that may impair the ability to provide informed consent Allergy to fish or omega‐3 supplements, or do not eat fish/fish‐containing substances for any reason Planned sample size: estimated enrolment 126 participants (from clinical trial register). Additional publication states estimated sample size of 176 (88 per group).
Interventions	Intervention: omega‐3 fatty acid, 1000 mg (administered as 2 soft gels, containing 683 mg eicosapentaenoic acid and 252 mg docosahexaenoic acid) twice daily for 6 weeks Comparator: placebo (administered as 2 placebo soft gels) twice daily for 6 weeks
Outcomes	Outcomes of interest in the review: Primary outcomes: Presence of normal olfactory function Not reported Serious adverse effects  Not reported Change in sense of smell Assessed with the BSIT (psychophysical testing). This is a 12‐item instrument, with a total score range of 0 to 12. Higher scores indicate better olfactory performance. Measured at 6 weeks after initiation of treatment. Secondary outcomes: Prevalence of parosmia Not reported Change in sense of taste Not reported Disease‐related quality of life Assessed with the mQOD‐NS. This is a 17‐item instrument, each item is graded 0 to 3, with a total score range of 0 to 51. Higher scores indicate better olfactory‐specific quality of life. Measured at 1 week, 2 weeks, 4 weeks and 6 weeks after initiation of treatment Other adverse effects (including nosebleeds/bloody discharge) Not reported Other outcomes reported by the study: SNOT‐22. This is a 22‐item instrument, with a total range of 0 to 110. Higher scores indicate more severe quality of life impact. It was designed to address the burden of symptoms of chronic rhinosinusitis, rather than anosmia or hyposmia. It will be measured at 1, 2, 4 and 6 weeks after initiation of treatment.
Starting date	15 July 2020
Contact information	Alfred‐Marc Iloreta Email: alfred-marc.iloreta@mountsinai.org
Notes	Estimated study completion date: June 2021 It is unclear from the description of this trial whether participants will have symptoms of olfactory disturbance for fewer than 4 weeks from the onset of COVID‐19. Correspondence with the study team has confirmed that they will recruit a mixed population, comprising individuals with fewer than and longer than 4 weeks of symptoms.