On the relationship between anosmia/dysgeusia and nonspecific immunoprophylaxis COVID-19
Authors: Berdyugina Olga V. , Gusev Evgeny Yu. 
Published: September 2022

The issues of non-specific immunoprophylaxis in the patients with new coronavirus infection have been raised since the WHO announced the COVID-19 pandemic. According to numerous studies, the new coronavirus infection is accompanied by manifestations of anosmia and dysgeusia. The purpose of this study was to perform a retrospective study of the relationships between nonspecific immunoprophylaxis of COVID-19 and conditions of anosmia/dysgeusia in the persons who underwent this infection in Sverdlovsk region over 2020.
We have studied clinical and laboratory data of 84 employees at the general medical institution providing emergency pediatric care. All participants suffered a single infection caused by SARS-CoV-2. Etiological diagnostics included mandatory virological PCR testing of biological samples. The concentration of antibodies to the virus was determined using a set of reagents for SARS-CoV-2-IgG detection (JSC Vector-Best, Novosibirsk, Russia). A sufficient part of this group (n = 41; 48.8% of total sample) reported self-administration of non-specific immunoprophylactic therapy of COVID-19 (without consulting a doctor) since the beginning of coronavirus pandemics. To this purpose, cholecalciferol, riamilovir, human recombinant IFNa-2b, umifenovir hydrochloride monohydrate, ascorbic acid, zinc acetate were used. In 58 cases (69% of total), clinical course of infection was complicated by loss of taste and sense of smell (group No. 1), in 26 people (31.0%), no changes in taste and sense of smell were detected (group No. 2). Statistical evaluation of the data was performed using STATISTICA v.12.5.192.5 package (StatSoft, Inc., USA). Along with basic statistics, cluster analysis was performed.
The use of cluster analysis allowed us to establish that there is a connection between the incidence of anosmia/dysgeusia and usage of distinct immunoprophylactic agents. In particular, the use of human recombinant IFNa-2b is protective in terms of reducing the number complications in COVID-19, especially, anosmia/dysgeusia caused by the new coronavirus. The use of this drug was associated with 8.5-fold decrease in the number of complications by (p = 0.03). Moreover, invasive intranasal usage of interferon, was associated with decreased hospitalization terms by 14.3% (p = 0.01); lower volume of lung tissue damage (p = 0.03), higher concentrations of IgG to SARS-CoV-2 at 2 months after reconvalescence (p = 0.001).
For the first time, data were presented on the relationship between usage of immunoprophylactic agents and manifestations of anosmia/dysgeusia in COVID-19. The protective role of human recombinant IFNa-2b has been shown in terms of reduced incidence of the disease complications, e.g., anosmia/dysgeusia, degree of lung damage, as well as development of an antiviral humoral immune response. The data obtained could be used to substantiate clinical recommendations for prevention of new outbreaks of coronavirus infection. The limitation of the obtained results is small number of cases, thus requiring additional studies in a wider sample of respondents.