Mechanisms of olfactory impairment in COVID-19: a systematic review


One of the symptoms of a new coronavirus infection (COVID-19) is a complete or partial violation of the sense of smell.

The aim of the work is to analyze the published results of scientific research on the mechanisms of olfactory impairment in COVID-19.

Material and methods. Research was conducted for publications in Pubmed on the problem of olfactory impairment in COVID-19 using terms indexed by MeSH. The systematic review was compiled in accordance with the checklist Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement (PRISMA).

Results. Publication’s analysis has shown that the existing ideas about conductive anosmia are insufficient to explain the causes of olfactory impairment caused by SARS-CoV-2. It has been established that ACE2 and TMPRSS2 receptors located on the surface of target cells are necessary for the penetration of a new coronavirus. It is known that these receptors are mainly located on the cells of the olfactory epithelium. The main hypothesis of olfactory impairment in COVID-19 is that anosmia/hyposmia is caused by damage not to neuronal cells (as previously assumed), but to the olfactory epithelium. There is no confirmation of the point of view about the damage of SARS-CoV-2 olfactory bulbs and olfactory neurons, since they do not express receptor proteins for the virus on their surface.

Keywords:anosmia; hyposmia; new coronavirus infection; SARS-CoV-2; COVID-19

Funding. The study had no sponsor support.

Conflict of interest. The authors declare no conflict of interest.

Contribution. Concept – Medeulova A.R.; collection and processing of material – Zhapar K.A., Kusainova D.G.; writing the text – Kusainova D.G.; editing – Medeulova A.R.

For citation: Medeulova A.R., Zhapar K.A., Kussainova D.G. Mechanisms of olfactory impairment in COVID-19: a systematic review. Infektsionnye bolezni: novosti, mneniya, obuchenie [Infectious Diseases: News, Opinions, Training]. 2022; 11 (2): 8–13. DOI:


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Yushchuk Nikolay Dmitrievich
Academician of the Russian Academy of Sciences, Professor, head of the Infectious Diseases and Epidemiology Department, President of the Moscow State University of Medicine and Dentistry named after A.I. Evdokimov, Board member of the National Scientific Infectiologists? Society.
Medicine today

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