Comparative analyses of COVID-19-related olfactory dysfunction and classical post-viral olfactory dysfunction: a...

Area of Science:

• Otolaryngology
• Infectious Diseases
• Neurology

Background:

• Olfactory dysfunction (OD) is a common COVID-19 symptom, but its characteristics differ from conventional post-viral OD (PVOD).
• COVID-19-OD characteristics also vary by viral subtype, necessitating comparative analysis.

Purpose of the Study:

• To compare clinical features and olfactory function between COVID-19-OD and PVOD.
• To investigate differences in OD characteristics among COVID-19 variants.

Main Methods:

• A multicenter retrospective study comparing 269 COVID-19-OD patients (2020-2022) with 380 PVOD patients (2017-2019).
• Analysis included patient demographics, olfactory cleft condition, and olfactory function from medical records.

Main Results:

• COVID-19-OD patients were younger, with higher olfactory cleft obstruction and more parosmia/phantosmia than PVOD patients.
• OD severity was milder in COVID-19-OD, even after age adjustment.
• Pre-Omicron COVID-19-OD cases were younger and had higher parosmia/phantosmia rates than Omicron cases.

Conclusions:

• COVID-19-OD and PVOD exhibit significant differences in clinical presentation and OD pathophysiology.
• Intra-COVID-19-OD variations across variants suggest underlying viral biological differences influencing olfactory dysfunction.