Aim – to identify the clinical features of low-symptomatic forms of COVID-19 coronavirus infection with accompanying olfactory dysfunction.

Material and methods. The study included the survey of people with a history of coronavirus infection conducted on the basis of the Central Research Institute of Epidemiology of Rospotrebnadzor. A total of 39,676 patients were interviewed, of whom 24,086 (60.70%) had suffered some form of new coronavirus infection COVID-19. Methods of descriptive statistics were used for processing the research results.

Results. Olfactory dysfunction was the only symptom of the acute period of COVID-19 infection in 4% of patients. The occurrence of this symptom depended on the dominant circulating genovariant, with the maximum of 7.8% during Alpha, the basic reproduction number (inverse relationship, Pearson correlation coefficient -0.9) and the age of the patient (more often in persons under 44 years of age). The occurrence of the symptom had no correlation with the patient's gender. Patients with olfactory dysfunction during the COVID-19 infection were significantly less likely (4.2% vs. 12.6%, P = 0.04) to require hospitalization and oxygen therapy (2.5% vs. 32.2%, P < 0.001).

Conclusion. Olfactory dysfunction may be the only symptom of the acute period of COVID-19 infection, which allows us to suggest its isolation into a separate form. The occurrence of this form depends on the dominant circulating genovariant, the basic reproductive number of the virus and the age of the patient. Patients with this form of coronavirus infection are less likely to require hospitalization and oxygen therapy.