Autoimmunity, COVID-19 Omicron Variant, and Olfactory Dysfunction: A Literature Review

Area of Science:

• Neuroscience
• Immunology
• Infectious Diseases

Background:

• Smelling impairment (anosmia) significantly reduces quality of life.
• Autoimmune conditions like Lupus, Sjögren Syndrome, and Rheumatoid Arthritis can cause anosmia.
• Anosmia is a common symptom of COVID-19.

Purpose of the Study:

• To review the commonalities and differences between autoimmune-associated anosmia and COVID-19 Omicron-associated anosmia.
• To explore the mechanisms behind reduced anosmia in Omicron-infected patients.

Main Methods:

• Literature review comparing olfactory dysfunction in autoimmune diseases and COVID-19.
• Analysis of proposed mechanisms for anosmia in relation to viral variants and immune response.

Main Results:

• Omicron variant may enter host cells via endocytosis, reducing reliance on TMPRSS2 in the olfactory epithelium.
• The Omicron variant elicits a less robust inflammatory and autoimmune response compared to other SARS-CoV-2 variants.
• These factors contribute to a lower prevalence of anosmia in Omicron-infected individuals.

Conclusions:

• The Omicron variant's distinct cellular entry and immune response mechanisms explain its lower association with anosmia.
• Understanding these differences aids in managing olfactory dysfunction related to infections and autoimmune disorders.