RESUMEN
Relevance. It is relevant to study the features of the formation and duration of the humoral immune response to a new coronavirus infection in a high-risk group of infection-among medical workers. Aims. To study the dynamics of the levels of specific antibodies (IgM and IgG) to SARS-CoV2 in unvaccinated MRs of the temporary infectious diseases hospital to assess the trends of the individual humoral immune response to a new coronavirus infection. Materials and methods. We monitored IgM and IgG to SARS-CoV-2 in 68 unvaccinated healthcare workers monthly from July 2020 to July 2021 by two-stage direct solid-phase ELISA using the test systems «SARS-CoV-2-IgG-ELISA-BEST» and «SARS-CoV-2-IgM-ELISA-BEST», Russia. Among them, there were 26.5% men and 73.5% women, the average age was 43.5 ± 1.51 years, doctors 52.9%, paramedical personnel 36.8% and junior staff 10.3%. 69.1% had a history of clinical manifestations of COVID19, among them 42.7% had a mild infection, 20.6% had a moderate infection, and 5.9% had a severe infection, 30.9% were asymptomatic. Statistical processing were carried out using the methods of variation statistics using the Excel statistical package and the WinPepi software product (version 11.65). Results. A decrease in the geometric mean value of IgM titers to SARS-CoV-2 (average monthly decrease of 6.40%) and an increase in the geometric mean value of IgG titers (average monthly increase of 4.26%). An individual assessment of the dynamics of antibodies from the day with the first positive result showed a decrease in the geometric mean values of antibody titers and IgM and IgG to SARS-CoV-2 (monthly average decrease of-23.56% and-1.18%, respectively). An individual assessment of the immune response made it possible to distinguish three groups according to the dynamics of IgM: M0-IgM in the blood were absent (50 ± 5.7446%);M1-IgM persisted for 1–2 months, followed by a rapid decrease in titer (16.176 ± 3.7943%);M2 – IgM remained in the blood for three or more months (33.824 ± 5.1033%). By the nature of the dynamics of IgG MR were divided into four troupes. With a downward trend in IgG titer: G0 – IgG does not exceed 95% of the upper confidence limit of the individual trend in any of the samples taken (19.118 ± 4.7686%), G1 – does not exceed 95% of the upper confidence limit of the individual trend starting from 3 months after the start observations (4.412 ± 2.4903%), G2 – there is an excess of 95% of the upper confidence limit of the individual trend starting from 3 months after the start of observation (69.118 ± 5.6027%);G3 – with a trend of increasing IgG titer (7.353 ± 3.1651%). Сonclusions. The results of serological monitoring as a whole indicate the formation of herd immunity in this cohort. Monitoring the intensity of the individual immune response to SARS-CoV-2 throughout the year reflects the natural course of the infectious process and is the basis for vaccination against COVID-19. The results of serological monitoring can be used to predict the epidemiological situation, plan specific and non-specific COVID-19, personalization of vaccination. © 2023, Numikom. All rights reserved.
RESUMEN
Background. The ongoing COVID-19 pandemic generates the urgent need of monitoring the herd immunity among healthcare workers as a high-risk group for infection. Aim. Determining the level and structure of population immunity to SARS-CoV-2 in the medical workers during the second peak of COVID-19 from August to November 2020. Material and methods. The study involved 15,158 medical workers from 91 medical organizations of the Republic of Tatarstan. The age of the examined stuff members varied from 18 to 74 years, the average age was 45.48±0.1016 years, most of them were women (13 627, 89.87±0.258%). Testing for the presence of total antibodies (immunoglobulin classes G, A and M) to SARS- CoV-2 was performed once by the enhanced chemiluminescence method. Statistical processing was carried out by methods of variation statistics and correlation analysis according to the Pearson method using MS Excel and WinPepi. Results. Seroprevalence to SARS-CoV-2 in medical workers was 35.23±0.388%. An increase in seropositive individuals level from 27.44±0.265% in August to 57.91±0.499% in November and an increase in the average geometric mean titer of total antibodies (immunoglobulin classes A, M, G) from 84.43 in August to 101.09 in November 2020 were detected. The level of individuals with antibodies increased with age from 18 to 59 years and decreased in group of 60-70 years. The largest proportion of seropositive to SARS-CoV-2 individuals was found among junior (42.01±1.384%) and middle grade (37.5±0.527%) medical staff of hospitals for patients with COVID-19, ambulance and emergency stations. Among the seropositive to the SARS-CoV-2 workers the proportion of asymptomatic forms of infection was 84.97±0.498%. According to the level of seroprevalence, municipal districts of the Republic of Tatarstan were divided into three groups: moderate - 8.9-39.0;average - 42.9-49.6, high level - 53.1-64.4. Сonclusion. An increase in seroprevalence to SARS-CoV-2 was revealed among medical workers of the Republic of Tatarstan from August to November 2020 during the second peak of COVID-19. © Eco-Vector, 2022. All rights reserved
RESUMEN
Background. The COVID-19 pandemic has become a serious challenge for all of humanity due to the rapid global spread, high frequency of severe forms, increased mortality and required the development of new approaches to managing epidemiological processes. Serological studies are the most important tool for monitoring the infectious process, identifying risk groups, assessing the effect of vaccines used and epidemiological projections. Purpose. Conducting serological monitoring in relation to the modern transferred new coronavirus infection determining the level and structure of population immunity to SARS-CoV-2 in the population of the Republic of Tatarstan;maintaining the period of spread of COVID-19 from August to December 2020. Materials and methods. The study involved 41 444 residents of the Republic of Tatarstan, who filled out questionnaires that included clinical, anamnestic data and an epidemiological history in relation to COVID-19, who were tested for the presence of common antibodies (IgG, IgA and IgM) to the SARS coronavirus. CoV-2 by the method of enhanced chemiluminescence on the VITROS 3600 analyzer using the VITROS Anti-SARS-CoV-2 Total Reagent Pack test systems. Statistical processing was carried out by methods of variation statistics and correlation analysis according to the Pearson method using MS Excel and WinPepi. Results. Seropositivity to SARS-CoV-2 in the population of the Republic of Tatarstan averaged 35.8 ± 0.235%. An increase in the level of seropositive persons was noted from 29.95 ± 0.674% in August to 68 ± 9.33% in December. The highest proportion of seropositive individuals was found in was found in the group of the able-bodied population aged 18–59 years. The average geometric titer of antibodies was 4.2 (4.09–4.31), among seropositive – 89.29 (88.13–90.46). In the social and professional structure of the population, the largest proportion of seropositive individuals was found in was found among production workers 40.35 ± 2.177, creative professions – 40 ± 9.798;health care 35.24 ± 0.389;34.26 ± 1.218 unemployed and 33.06 ± 2.479 civil servants. Among the residents of the Republic of Tatarstan, seropositive to the SARS-CoV-2 virus, the proportion of asymptomatic forms of infection was 82.59 ± 0.446%. Сonclusions. There is a positive dynamics of seropositivity among the population of the Republic of Tatarstan. The results of sero-epidemiological monitoring can be used to predict the epidemiological situation, plan measures for specific and non-specific prophylaxis of COVID19. ©Sadykov MN et al.