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Bull Exp Biol Med ; 173(6): 734-739, 2022 Oct.
Article in English | MEDLINE | ID: covidwho-2094660


IgM and IgG antibodies to the SARS-CoV-2 virus are detected in subjects who have recovered from COVID-19; IgM antibodies persist in a 1/3 of infected subjects up to 12 months from the moment of the disease, while IgG antibodies are present in the vast majority of cases (97%; medium and high levels antibodies were registered in 85% of cases). By the 12th month, 40% of those who recovered still have a very high level of IgG antibodies to the S-protein (>500 BAU/ml). In the feces, urine, and blood serum of patients with long-term persistent IgM antibodies, no coronavirus antigens were detected. After vaccination with the Gam-COVID-Vac vaccine, IgG antibodies to the S-protein are detected in 100% of cases and remain at a high level for 4 months, by the 5-6th month, the level of antibodies decreases. During revaccination, the level of IgG antibodies to S-protein reaches high values earlier than during primary vaccination, and remains high for 4 months (observation period). The blood sera of recovered and vaccinated patients have a high virus-neutralizing activity (at least 1:80), while its level is somewhat higher in recovered patients.

Antibodies, Viral , COVID-19 , Humans , Immunization, Secondary , COVID-19/prevention & control , SARS-CoV-2 , Vaccination , Immunoglobulin M , Immunoglobulin G
Infektsionnye Bolezni ; 19(3):5-13, 2021.
Article in Russian | Scopus | ID: covidwho-1614429


We evaluated humoral immunity (presence of specific IgM and IgG) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among healthcare professionals providing inpatient care for individuals with COVID-19. Objective. To detected and measure the level of anti-SARS-CoV-2 antibodies in healthcare professionals and to identify how many of them contacted with COVID-19 patients, including those who had asymptomatic or subclinical disease. Materials and methods. Anti-SARS-CoV-2 antibodies were detected using enzyme-linked immunosorbent assay (ELISA) with the ‘SARS-CoV-2-ELISA-Vector’ kit for IgG (State research Center of Virology and Biotechnology ‘Vector’) and ‘SARS-CoV-2-IgG- ELISA-BEST’ and ‘SARS-CoV-2-IgМ-ELISA-BEST’ kits for IgM and IgG (Vector-Best LLC). Samples were collected in several healthcare institutions of Moscow and in G.N.Gabrichevskiy Moscow Research Institute of Epidemiology and Microbiology. A total of 24,373 serum specimens from 74 healthcare institutions were tested. All study participants filled in special questionnaires. Results. Among 24,373 healthcare professionals tested in this study, 5,382 people were IgG-positive to SARS-CoV-2 (seroprevalence index 22.1%). The seropositivity rate was 21.5% in senior medical staff, 22.2% in nursing professionals, and 22.8% in medical assistants/technicians. We found that the proportion of SARS-CoV-2 seropositive individuals had changed over time, gradually increasing from 17.9% in April 2020 to 37.6% in December 2020. The proportion of SARS-CoV-2 seropositive people doubled among senior medical staff and nursing professionals during the year. The proportion of individuals with asymptomatic or subclinical COVID-19 was 13.8%. Conclusion. The methodological approaches used in this study allowed us to assess the humoral immunity to SARS-CoV-2 among healthcare professionals in Moscow. Our findings can be used for further improvement of anti-epidemic measures in healthcare institutions. © 2021, Dynasty Publishing House. All rights reserved.

Bull Exp Biol Med ; 171(2): 230-233, 2021 May.
Article in English | MEDLINE | ID: covidwho-1525548


The presence of IgG and IgM antibodies in the venous blood of 76 patients with confirmed COVID-19 infection was determined by ELISA using Russian test systems. Different levels of IgM antibodies to N-protein and receptor binding domain of the Spike protein (RBD) were revealed. The dynamics of IgG antibodies to the whole virion antigen and recombinant antigens showed high values on weeks 4-5 of the disease. The level of IgG antibodies to Nprotein remained low throughout the observation period. The characteristic dynamics of IgG measured using test systems with sorbed whole virion or recombinant spike proteins reflects the duration of the disease.

Antibodies, Viral/blood , Antigens, Viral/immunology , COVID-19/diagnosis , Coronavirus Nucleocapsid Proteins/immunology , Immunoglobulin G/blood , Immunoglobulin M/blood , Spike Glycoprotein, Coronavirus/immunology , Antigens, Viral/genetics , COVID-19/blood , COVID-19/immunology , COVID-19/virology , Coronavirus Nucleocapsid Proteins/genetics , Enzyme-Linked Immunosorbent Assay , Humans , Immunity, Humoral , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/genetics , Time Factors , Virion/genetics , Virion/immunology