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Background. The COVID-19 pandemic has become a substantial global health crisis, unparalleled in world history. Infection dynamics can have specific characteristics in different countries due to social, economic, climatic, or geographic factors. Aim(s): to study features of SARS-CoV-2 collective immunity among the Armenian population. Materials and methods. A cross-sectional, randomized study of collective immunity was carried out according to a program developed by Rospotrebnadzor and the St. Petersburg Pasteur Institute, taking into account WHO recommendations. The study was approved by the ethics committees of the National Center for Infectious Diseases (Armenia) and the St. Petersburg Pasteur Institute (Russia). A volunteer cohort was formed (N = 6057), randomized by age and region. The study's analysis included: shares and distributions of antibodies (Abs) to nucleocapsid (Nc) antigen (Ag) and receptor binding domain (RBD) S-1 Ag in the cohort;and quantitative determination of these Abs by ELISA. During the survey, a history of vaccination was indicated by 4395 people. Results. Overall seropositivity formed in the whole cohort (by April 14, 2022) was 98.6% (95% CI: 98.1-98.7). It did not depend on age, place of residence, or occupation. When quantifying Nc and RBD Abs, the proportions of volunteers with Nc Ab levels of 1-17 BAU/ml and RBD Ab levels of 22.6-220 BAU/ml were the smallest, amounting to 6.9% (95% CI: 6.2-7.5) and 20.4% (95% CI: 19.4-21.4), respectively. With increasing serum concentrations (Nc > 667 BAU/ml, RBD > 450 BAU/ml), the proportions of individuals with the corresponding levels were 20.2% for Nc (95% CI: 19.2-21.3) and 54.2% for RBD (95% CI: 52.9-55.5). Vaccination coverage was 72.6% (95% CI: 71.5-73.7). The most frequently used were Sinopharm/BIBP (32.4%), AZD1222 (22.3%), and Gam-COVID-Vac (21%). The remaining vaccines (CoronaVac, mRNA-1273, BNT162b2, CoviVac) were used by 24.3% of vaccinated individuals. When summing vaccines by platform, it was found that: vector vaccines were used in 40.34% (95% CI: 33.57-42.39) of cases;whole-virion vaccines were used in 26.83% (95% CI: 24.76-32.20);and mRNA vaccines were used in 6.33% (95% CI: 4.84-8.91). Conclusion. The epidemic situation in Armenia by April 2022 was characterized by a high level of collective immunity, independent of age or regional factors. Vector and whole-virion vaccines have been used most widely.Copyright © Popova A.Yu. et al., 2023.
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Confirming detected SARS-CoV-2-specific antibodies is necessary to reveal immune response in COVID-19 convalescent subjects as well as to conduct population studies by screening for specific antibodies to assess rate of COVID-19 prevalence. With this purpose St. Petersburg Pasteur Institute was the first in Russia to develop the ELISA kit for the quantitative determination of human IgG to the SARS-CoV-2 nucleocapsid (N-CoV-2-IgG PS). Arbitrary units (AU/ml) were used to assess the level of antibodies. The data shown in AU/ml were recalculated later to the international units (BAU/ml) in accordance with established the First WHO International Standard for anti-SARS-CoV-2 human Immunoglobulin. Comparing the data of the N-CoV-2-IgG PS calibration curve with those of the First WHO International Standard for anti-SARS- CoV-2 human Immunoglobulin revealed a complete inter-assay association (r = 0.999, R-2 = 0.997) allowing to find that 1BAU/ml = 5.97 AU/ml. The aim of the study was to characterize the "SARS-CoV-2 protein N Human IgG Quantitative ELISA Kit" (N-CoV-2-IgG PS), compare quantitative and qualitative data of ELISA kits, assess a correlation between the binding antibodies to SARS-CoV-2 N proteins and the neutralizing antibodies against SARS-CoV-2. The data of correlation analysis of the 83 COVID-19 convalescent blood plasma samples a significant relationship between the antibodies quantitative values and titers SARS-CoV-2-specific antibody (r = 0.8436, R-2 = 0.7802) as well as a moderate relationship between antibody concentration and positivity index (r = 0.6648, R-2 = 0.3307), assessed by Chaddock scale. Comparing concentration of N-protein binding antibodies with neutralizing antibody titers level uncovered data consistency obtained by quantitative and virus microneutralization assays (r = 0.7310, R-2 = 0.6527) used in parallel to analyze 80 blood plasma samples obtained from COVID-19 patients and convalescents. AUC under the ROC curve comprised 0.701 (P < 0.0001) evidencing about a satisfactory informative value for "N-CoV-2-IgG PS" compared with microneutralization assay. In addition, the efficacy of the "N-CoV-2-IgG PS" was 95%, while the positive and negative prognostic value was 97% and 87%, respectively. The data obtained confirmed a correlation between N-protein binding antibody level and neutralizing antibody titer. Checking inter-assay agreement evidenced about acceptance for informativeness and efficacy of using "N-CoV-2-IgG PS", thereby confirming an opportunity to apply the Kit to screen for SARS-CoV-2 N protein-specific IgG antibody level and assess seroprevalence in diverse population cohorts.
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In our study, we aimed to evaluate the significance of specific cytokines in blood plasma as predictive markers of COVID-associated mortality. Materials and methods. In plasma samples of 29 patients with PCR-confirmed COVID-19 we measured the concentrations of 47 molecules. These molecules included: interleukins and selected pro-inflammatory cytokines (IL-1alpha, IL-1beta, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-9, IL-12 (p40), IL-12 (p70), IL-13, IL-15, IL-17A/CTLA8, IL-17-E/IL-25, IL-17F, IL-18, IL-22, IL-27, IFNalpha2, IFNgamma, TNFalpha, TNFbeta/Lymphotoxin-alpha(LTA));chemokines (CCL2/MCP-1, CCL3/MIP-1alpha, CCL4/MIP-1beta, CCL7/MCP-3, CCL11/Eotaxin, CCL22/MDC, CXCL1/GROalpha, CXCL8/IL-8, CXCL9/MIG, CXCL10/IP-10, CX3CL1/Fractalkine);anti-inflammatory cytokines (IL-1Ra, IL-10);growth factors (EGF, FGF-2/FGF-basic, Flt-3 Ligand, G-CSF, M-CSF, GM-CSF, PDGF-AA, PDGFAB/BB, TGFalpha, VEGF-A);and sCD40L. We used multiplex analysis based on xMAP technology (Luminex, USA) using Luminex MagPix. As controls, we used plasma samples of 20 healthy individuals. Based on the results, we applied Receiver Operating Characteristic (ROC) analysis and Area Under Curve (AUC) values to compare two different predictive tests and to choose the optimal division point for disease outcome (survivors/non-survivors). To find optimal biomarker combinations, we as used cytokines concentrations as dependent variables to grow a regression tree using JMP 16 Software.Results. Out of 47 studied cytokines/chemokines/growth factors, we picked four pro-inflammatory cytokines as having high significance in evaluation of COVID-19 outcome: IL-6, IL-8, IL-15, and IL-18. Based on the results received, we assume that the highest significance in terms of predicting the outcome of acute COVID-19 belongs to IL-6 and IL-18. Conclusion. Analyzing concentrations of IL-6 and IL-18 before administering treatment may prove valuable in terms of outcome prognosis. Copyright © Arsentieva N.A. et al., 2022.
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In our study, we aimed to evaluate the significance of specific cytokines in blood plasma as predictive markers of COVID-associated mortality. Materials and methods. In plasma samples of 29 patients with PCR-confirmed COVID-19 we measured the concentrations of 47 molecules. These molecules included: interleukins and selected pro-inflammatory cytokines (IL-1alpha, IL-1beta, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-9, IL-12 (p40), IL-12 (p70), IL-13, IL-15, IL-17A/CTLA8, IL-17-E/IL-25, IL-17F, IL-18, IL-22, IL-27, IFNalpha2, IFNgamma, TNFalpha, TNFbeta/Lymphotoxin-alpha(LTA));chemokines (CCL2/MCP-1, CCL3/MIP-1alpha, CCL4/MIP-1beta, CCL7/MCP-3, CCL11/Eotaxin, CCL22/MDC, CXCL1/GROalpha, CXCL8/IL-8, CXCL9/MIG, CXCL10/IP-10, CX3CL1/Fractalkine);anti-inflammatory cytokines (IL-1Ra, IL-10);growth factors (EGF, FGF-2/FGF-basic, Flt-3 Ligand, G-CSF, M-CSF, GM-CSF, PDGF-AA, PDGFAB/BB, TGFalpha, VEGF-A);and sCD40L. We used multiplex analysis based on xMAP technology (Luminex, USA) using Luminex MagPix. As controls, we used plasma samples of 20 healthy individuals. Based on the results, we applied Receiver Operating Characteristic (ROC) analysis and Area Under Curve (AUC) values to compare two different predictive tests and to choose the optimal division point for disease outcome (survivors/non-survivors). To find optimal biomarker combinations, we as used cytokines concentrations as dependent variables to grow a regression tree using JMP 16 Software.Results. Out of 47 studied cytokines/chemokines/growth factors, we picked four pro-inflammatory cytokines as having high significance in evaluation of COVID-19 outcome: IL-6, IL-8, IL-15, and IL-18. Based on the results received, we assume that the highest significance in terms of predicting the outcome of acute COVID-19 belongs to IL-6 and IL-18. Conclusion. Analyzing concentrations of IL-6 and IL-18 before administering treatment may prove valuable in terms of outcome prognosis. Copyright © Arsentieva N.A. et al., 2022.
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Background. The ongoing pandemic of the novel coronavirus infection (COVID-19) draws attention to the significance of molecular and genetic monitoring of the SARS-CoV-2 spread among the population of the Russian Federation. The aim of the study was to analyze the dynamics of circulation of SARS-CoV-2 genetic variants in Russia. Materials and methods. The analysis of the circulation dynamics for SARS-CoV-2 genetic variants in Russia was carried out, covering the period from 28/12/2020 to 26/6/2022. The analysis included the data from Rospotrebnadzor Report No. 970 "Information about Infectious Diseases in Individuals with Suspected Novel Coronavirus Infection" and the Virus Genome Aggregator of Russia (VGARus). The presence of SARS-CoV-2 RNA was confirmed by the real-time reverse transcription polymerase chain reaction. The primer panels developed at the Central Research Institute of Epidemiology were used for amplification of genomic fragments and the subsequent sequencing. Results and discussion. Using the Russian VGARus platform developed by the Central Research Institute of Epidemiology, we received the data on mutational variability of SARS-CoV-2. By monitoring the circulation of SARS-CoV-2 genetic variants in Russia from 28/12/2020 to 26/6/2022, we found that Delta and Omicron genetic variants prevailed at different stages of the epidemic. Conclusion. The data of molecular and genetic studies are an essential component of epidemiological surveillance, being critically important for making executive decisions aimed at prevention of further spread of SARS-CoV-2 and laying the groundwork for creating new vaccines. © 2022, Central Research Institute for Epidemiology. All rights reserved.
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Objective: To study the seroprevalence of SARS-CoV-2 antibodies (AB) in children in the 2nd year of the COVID-19 pandemic in Russia. Materials and methods: Prospective cohort study. The seroprevalence research was conducted among 3670 children aged 1 to 17 y/o from 26 modelling regions of Russia (that have been participating earlier in the five stages of seromonitoring during 2020-2021). The serological testing was carried out in December, 2021. The work was carried out according to a unified methodology set by the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being with the Pasteur Institute of Epidemiology and Microbiology (Saint Petersburg, Russia). The plasma was obtained from 3 ml of venous blood, in which the level of AB to nucleocapsid (NC), and the SARS-CoV-2 receptor-binding domain (RBD) was determined by immunoferment method using reagents for qualitative and quantitative analysis. Results: The analysis of AB seroprevalence to NC and RBD showed the statistically significant increase in the share of seropositivity to RBD in children of all modelling regions (p<0.05). The most seropositive volunteers contained low levels of AB: 31.3-125.6 BAU/ml NC and 22.6-220 BAU/ml RBD. An increase in the level of AB to NC and RBD was accompanied by a decrease in the percentage of seropositive patients. Evaluating the contribution of children to the level of humoral immunity, convalescents (had been ill shortly before the examination), the «anamnesis» (had been ill at previous stages of seromonitoring) and asymptomatic (had been asymptomatically ill) groups were distinguished. The maximum contribution was made by children with asymptomatic cases of COVID-19 in anamnesis: In 82.3% (95% CI 81.1-83.6), of which 76.9% (95% CI 75.5-78.3) AB detected to RBD. The contribution of children of two other groups to the overall level of humoral immunity was 33 times less. Conclusion: Statistically significant predominance of AB to RBD above AB to NC and their main contribution to the level of humoral immunity to SARS-CоV-2 (p<0.001).
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The aim of the study was to assess the seroprevalence to the SARS-CoV-2 nucleocapsid in the population of the Nizhny Novgorod region against the background of COVID-19. Materials and methods. The work was carried out according to a unified methodology developed by Rospotrebnadzor with the participation of the St. Pasteur. The selection of volunteers for the study was carried out by the method of questioning and randomization. The exclusion criterion was active COVID-19 infection at the time of the survey. A total of 2829 volunteers were surveyed, divided into seven age groups. Venous blood samples were taken from all volunteers from EDTA vacutainers. In the blood plasma, the content of specific IgG to the SARS-CoV-2 nucleocapsid was determined by the enzyme immunoassay. Results. The population level of immunity to SARS-CoV-2 among the surveyed volunteers was 8,4% (95% CI 7,4–9,5). The largest proportion of seroprevalent persons was found among children aged 1–6 years — 15,9% (95% CI 8,2–26,7), the smallest in the group of volunteers aged 18–29 years — 6,0% (95% CI 3,8–8,9). During 3-stage serological monitoring, the proportion of seroprevalent volunteers increased to 22,5% (95% CI 20,3–24,9)%, or almost 2 times from the initial level (p<0,05). of the population of the Semenovsky district (22,7% (95% CI 10,9–41,8)), the smallest — in the city of Dzerzhinsk (2,4% (95% CI 0,5–7,1)%) Among convalescents after COVID-19, specific antibodies were detected in 47,2% (95% CI 30,5–69,6), which is 5,6 times higher than the average for the population. Among those who had verified contact with patients, specific IgG were detected in 17,6% (95% CI 12,9–23,5), which is 2,1 times higher than the average for the population. Among asymptomatic persons who had a positive PCR result, 53,3% (95% CI 30,5–86,6) were seropositive, which is 6,3 times higher than the average for the population. Of 225 seropositive people, 188 (88,4% (95% CI 76,6–101,6)) had the disease asymptomatic. Conclusion. The relatively low proportion of seroprevalent persons among the population may indicate a significant risk of further development of the epidemic process caused by COVID-19 in the territory of the Nizhny Novgorod region. © 2021,HIV Infection and Immunosuppressive Disorders. All Rights Reserved.
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Introduction. The first pandemic in the 21st century, caused by the pathogenic representative of the coronavirus SARS-CoV-2, began in the Chinese city of Wuhan, where the first outbreak of coronavirus pneumonia was recorded in December 2019. The disease spread so quickly around the world that already on February 11, 2020, WHO was forced to declare a pandemic of the “coronavirus disease 2019” COVID-19. The first case of COVID-19 in the Stavropol Territory was registered on March 20, 2020, and three weeks later, starting from the 15th week of the year, a steady increase in the incidence began, which lasted until the 52nd week. During the study period, the incidence increased from 21.1 to 28.3 per hundred thousand of the population. Growth 1.3 times. Purpose: to determine the dynamics of population immunity among the population of the Stavropol Territory in 2020-2021. during the period of an epidemic increase in the incidence of COVID-19. Materials and methods. The SARS-CoV-2 study was carried out according to a unified methodology within the framework of the program for assessing the population immunity of the population of the Russian Federation, developed by Rospotrebnadzor with the participation of the St. Pasteur. In total, 2688 people were examined, divided into 7 age groups. In the examined individuals, the level of specific IgG to the SARS-CoV-2 nucleocapsid was determined by the enzyme immunoassay. Results. The level of seroprevalence among residents of the Stavropol Territory was 9.8%. The largest proportion of seropositive individuals was found in the age groups 1-6 and 7-13 years old (19.2% and 19.7%, respectively). Seroprevalence had no gender differences and ranged from 9.3% to 10.8%. When assessing the distribution of the proportion of seropositive persons in different geographic territories of the region, it was found that the maximum proportion was found in the Kochubeevsky district (23.1%), the minimum in Kislovodsk (7.7%). Among convalescents, the content of specific antibodies to SARS-CoV-2 was noted in 73.3%, which is 7.8 times higher than the average population level. When conducting seromonitoring in the 2nd half of 2020, a 10-fold increase in seroprevalence was recorded, accompanied by a decrease in incidence from the 5th week of 2021. Among asymptomatic volunteers in whom SARS-CoV-2 RNA was detected by the polymerase chain reaction, antibody titers to viruses were found in 78.6%, which corresponds to the seroprevalence of convalescents. The proportion of seropositive persons among those who have come into contact with CO-VID-19 patients was 16.4%, (1.8 times higher than the average for the population). Out of 262 seroprevalent volunteers, the asymptomatic form of SARS-CoV-2 was detected in 92% of the examined, which indicates a significant role of the number of asymptomatic forms of infection in the epidemic process of COVID-19. Conclusion. The results of assessing the population immunity of the population of the Stavropol Territory indicate that it has not yet reached the threshold level at which a decrease in the intensity of the COVID-19 epidemic process can be expected. © 2021 Interregional public organization Association of infectious disease specialists of Saint-Petersburg and Leningrad region (IPO AIDSSPbR). All rights reserved.
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The Bioethics Committee of Belarus and the local ethics committee of the St. Petersburg Pasteur Institute approved the study. Selection of participants was carried out using a questionnaire method and online technology (internet, cloud server). Volunteers were randomized into seven age groups (years of age): 1–17;18–29;30–39;40–49;50–59;60–69;and 70+. Regional randomization ensured proportional representation of volunteers from each region, and no more than 30 people were included from one enterprise. In accordance with manufacturer instructions, blood plasma samples were analyzed for: IgG antibodies (Abs) to the SARS-CoV-2 nucleocapsid (Nc) using a quantitative ELISA test system;and IgG Abs to the receptor binding domain (RBD) of the SARS-CoV-2 S (spike) surface glycoprotein using a qualitative ELISA test system. Statistical processing was carried out using Excel 2010 and other software. Statistical differences were designated as significant when p < 0.05, unless otherwise indicated. Results. The level of seroprevalence, in terms of Abs to Nc among the Belarusian population, was 38.4% (95% CI 37.6–45.4). The highest Ab levels were found among individuals in older age groups (50-70+ years old). The lowest were found in children 1–17 years old and in young people 18–39 years old The distribution of seroprevalence across Belarusian regions was relatively homogeneous, with the exception of the Minsk Region, where a statistically significant decrease in the indicator was noted. In terms of profession, the largest share of seropositive individuals was found among transportation workers;the smallest was found in business. The moderate COVID-19 incidence has not led to a dramatic increase in the number of contacts. The base reproduction number (R0) was 1.3. In the Republic of Belarus, there was a moderate level of asymptomatic COVID-19 among seropositive individuals (45.3% [95% CI 44.0–46.7]). This form of infection was observed most often among children aged 1–17 years old (65.0% [95% CI 61.3–68.6]). In parallel with seroprevalence assessment, SARS-CoV-2 vaccination was carried out. We used two vaccines: Gam-COVID-Vac (also known as Sputnik V, developed by Gamaleya National Center for Epidemiology and Microbiology, Russia);and BBIBP-CorV (Sinopharm, PRC). Vaccination against SARS-CoV-2 was accompanied by an increase in the level of anti-RBD Abs (95% [95% CI 94.7–96.7]). Taking into account the vaccination of a subset of the population with BBIBP-CorV, the overall herd immunity, inferred from the analyzed indicators (presence of anti-Nc or anti-RBD Abs), was 47.1% (95% CI 46.3–48.0). Conclusion. COVID-19 in Belarus was characterized by a moderately pronounced course of the epidemic process. The threshold level of herd immunity to SARS-CoV-2 has not yet been reached, as a result of which the conditions for progression of the epidemic remain.
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The aim: to study the structure and dynamics of population immunity to SARSCoV-2 of the population of the Southern Regions of the Far East (SRFE): Khabarovsk, Primorsky Krai and Amur Region during the COVID-19 epidemic in 2020. Materials and methods. The work was carried out according to the program for assessing population immunity to SARS -CoV-2 of the population of the Russian Federation according to the methodology developed by the Rospotrebnadzor with the participation of the St. Petersburg Pasteur Institute. The study was approved by the ethical committee of the St. Petersburg Pasteur Institute. The selection of participants was carried out by a questionnaire method using cloud technologies. The volunteers were randomized by age by stratification into 7 age groups: 1–17, 18–29, 30–39, 40–49, 50–59, 60–69, 70+ years old. Territorial randomization consisted in limiting the engaging of volunteers – no more than 30 people from one enterprise. After the initialcross-sectionalstudy, a 3-stage seromonitoring was carried out, in which the same volunteers participated. Antibodies to the SARS-CoV-2 nucleocapsid were determined in peripheral blood serum by the enzyme immunoassay using an appropriate set of reagents produced by the State Scientific Center for Medical and Biological Sciences of the Rospotrebnadzor (Obolensk). Statistical analysis was performed using the Excel package. The confidence interval for the proportion was calculated using the A. Wald, J. Wolfowitz method with A. Agresti, B.A. Coull’s correction. The statistical significance of the differences was calculated online using a specialized calculator. The statistical significance of the differences was assessed with a probability of p < 0.05, unless otherwise indicated. Results. In a comparative analysis, the highest morbidity was observed in the Khabarovsk Territory, the lowest – in the Primorsky Territory. The level of seroprevalence among the population of the region was 19.6 % (95 % CI: 18.2–21.1) in the Khabarovsk Territory, 19.6 % (95 % CI: 18.1–21.2) in the Primorsky Territory19,6 % and 45,5 % (95 % CI: 43.7–47.3) in the Amur region. The highest seroprevalence was noted among 1–17 years old children, mainly due to the subgroup of 14–17-years-olds. The smallest proportion of seropositive was found among 40–49-year-olds in the Khabarovsk Territory (14.7 %, 95 % CI: 11.2–18.6), 18–28-year-olds in the Primorsky Territory (13.3 %, 95 % CI: 10.0–17.1) and 30–39-year-olds in the Amur Region (36.3 %, 95% CI: 31.7–41.6). No statistically significant dependence of seroprevalence on territorial and occupational factors has been established, with the exception of an increase in the proportion of seropositive medical workers in Primorsky Territory. In the process of 3-stage seromonitoring, a regular increase in the proportion of seropositive people was revealed in all SRFE. The resulting tendency is correctly describedby a second-order polynomial. Arelationship was revealed between the number of convalescents and persons in contact with them, which made it possible to calculate the base reproductive number (R0) in the range from 1.4 (Primorsky Territory) to 2.4 (Amur Region). Analysis of seroprevalent volunteers showed that the number of asymptomatic individuals varied from 94.1 % (95 % CI: 92.8–95.3) to 98.3 % (95 % CI: 98.8–99.2). This indicates that most of the volunteers had COVID-19 asymptomatically. Conclusions. A comparative study showed the prevalence of seroprevalence in the Amur Region compared with the Khabarovsk and Primorsky Territories. The relationship between the number of convalescents and persons in contact with them was noted. The value of the base R0 is calculated. It has been shown that more than 90 % of seropositive individuals in the COVID-10 SRFE were asymptomatic. © 2021 Scientific Centre for Family Health and Human Reproduction Problems. All rights reserved.
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AIM: To determine the level of SARS-CoV-2 seroprevalence among the Novosibirsk Region population against the background of the COVID-19 pandemic. MATERIAL AND METHODS: The work was carried out in 2 phases: 1) a cross-sectional cohort study performed 28.06- 15.07.2020; 2) longitudinal cohort 3-stage seromonitoring: 1st stage 28.06-15.07.2020; 2nd 14.09-04.10.2020; 3rd 10-30.12.2020 The work was carried out according to a unified methodology developed by Rospotrebnadzor with the participation of St-Petersburg Pasteur Institute, taking into account the recommendations of the WHO. IgG antibodies to the SARS-CoV-2 nucleocapsid protein were detected by ELISA using a kit of reagents produced by the SRCMSB (Obolensk) according to the manufacturer's instructions. Statistical analysis was performed using Microsoft Excel 2010 and other programs. RESULTS: The seroprevalence in the region's population was 9.1% (95% CI 8.0-10.2): maximum in children 14-17 years old (17.6%, 95% CI 12.3-23.9) and persons over 75 years (14.8%, 95% CI 11.4-18.8), minimum among persons 30-39 years old (4.9%, 95% CI 3.0-8.0). Increased rate was noted among the unemployed (15.4%, 95% CI 9.9-17.1) and other individuals (13.0%, 95% CI 8.6-18.5). Seroprevalence was 33.3% (95% CI 16.3-59.0) in COVID-19 convalescents and 19.0% (95% CI 13.9-25.0) in contact persons. More than 94.7% (95% CI 91.2-97.2) of seropositive individuals were asymptomatic. During the serological monitoring, seroprevalence increased from 7.4% (95% CI 6.2-8.9) at 1st stage 1 to 12.4% (95% CI 10.6-14.3) at 2nd , and 31% (95% CI 28.8-33.3) at 3rd stage. CONCLUSION: SARS-CoV-2 herd immunity has not reached the threshold level, this does not exclude exacerbation of the epidemic process.
Subject(s)
COVID-19/epidemiology , COVID-19/immunology , Immunity, Herd , Pandemics , SARS-CoV-2/immunology , Adolescent , Adult , Aged , Child , Female , Humans , Male , Middle Aged , Seroepidemiologic Studies , Siberia/epidemiologyABSTRACT
Purpose. Determination of the SARS-CoV-2 population humoral immunity among the population of the Krasnoyarsk Territory during the COVID-19 epidemic. Materials andmethods. The study was carriedoutas a partof projectfor assessing population immunity to SARS-CoV-2 among the population of Russian Federation using unified methodology developed by Rospotrebnadzor, with the participation of the Research Institute for Epidemiology and Microbiology named by Pasteur, and taking into account the recommendations of the WHO. The work involved 2907 volunteers, selected by the online survey and randomization by age and territory. All volunteers were divided into 7 age groups: 1–17, 18–29, 30–39, 40–49, 50–59, 60–69, 70 and older (70+), including a total 246–449 people. Population immunity testing was carried out during the formation of groups (1st stage), and then twice more, with the interval of 6–8 weeks. Serum was obtained from venous blood samples obtained from volunteers, in which antibodies to the SARS-CoV-2 nucleocapsid were determined by the enzyme immunoassay. The results were analyzed by methods of nonparametric statistics: median, interquartile range, rank correlation coefficient were calculated in the Excel statistical package. The confidence interval to seroprevalence indicators (95% CI) was calculated using the WinPepi statistical package (version 11.65). The statistical significance of the differences was assessed with a probability level of p ≤ 0.05. Results. The seroprevalence of the population of the Krasnoyarsk Territory during the 5-month period of seromonitoring had increased 3.3 times from 12.8% (95% CI 11.3–14.4) to 41.7% (95% CI 39.4–4.0), while the grouping by age had not revealedany peculiarities throughoutthe study. The trendtowards a decrease in the incidence was formedon the 6thweekof2021. The seroprevalence ofconvalescents after COVID-19 during the initial testing was 61.5% (95% CI 40,6–79.8), among those who were in contact with patients with COVID-19 or convalescents – 23.8% (95% CI 13.9–36.2) . Among the volunteers, 347 seropositive persons were identified, 324 of which were observed asymptomatic course. Conclusion. The structure of the population humoral immunity to SARS-CoV-2 of he population of the Krasnoyarsk Territory has been investigated. It was found that an increase in seroprevalence to 41.7% (95% CI 39.4–4.0) was accompanied by a decrease in morbidity. © 2021 Scientific Centre for Family Health and Human Reproduction Problems.
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Relevance. At the end of 2019, the world was confronted with a novel coronavirus (SARS-CoV-2), In January 2020, WHO declared an epidemic related to SARS-CoV-2, a health emergency of international importance, and in March characterized the spread of the world. diseases like a pandemic. Purpose of the study. Conduct a comparative analysis of the seroprevalence of the population of the Sverdlovsk and Chelyabinsk regions – the largest administrative territorial entities of the Middle and Southern Urals – against the backdrop of the COVID-19 pandemic. Materials and methods. The work was carried out under the program of the first stage of assessing the seroprevalence of the population of the Russian Federation according to a unified methodology developed by Rospotrebnadzor of the Russian Federation with the participation of the Saint Petersburg Pasteur Institute. The selection of participants was carried out by the method of questioning and randomization. The presence of antibodies to the SARS-CoV-2 nucleocapsid was determined in blood serum by the enzyme immunoassay. Results. Comparative analysis of the results showed that the incidence rate of COVID-19 in the Chelyabinsk region was consistently lower, and the seroprevalence at the first stage of the study was statistically significantly higher (p <0/05) than in the Sverdlovsk region. It was found that the incidence in both regions had a direct correlation with population density (r = 0.59;p <0.05). There were no differences between the compared areas in terms of seroprevalence among convalescents, people who had contact with COVID-19 patients, and asymptomatic volunteers with a positive PCR test. When analyzing seroprevalent volunteers in both regions, it was shown that the number of asymptomatic individuals varied within 94.4 ± 1.2% – 95.0 ± 0.95%. These data indicate that the majority of volunteers tolerated COVID-19 asymptomatically. Conclusions. A comparative study showed a statistically significant predominance of seroprevalence among the population of the Chelyabinsk region. It was found that an increase in seroprevalence at the population level was accompanied by a decrease in morbidity. Shown is a direct relationship between population density and the incidence rate. More than 90% of seropositive individuals in the compared areas showed asymptomatic course of coronavirus infection. © 2021, Numikom. All rights reserved.
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Purpose of the study. Determination of the level and structure of population immunity to SARS-CoV-2 among the population of the Murmansk region against the background of the incidence of COVID-19. Materials and methods. The study was carried out according to a unified method for determining the seroprevalence of the population, developed by Rospotrebnadzor with the participation of the St. Petersburg Pasteur Institute. A total of 3117 volunteers were examined, distributed into 7 age groups. The content of antibodies to SARS-CoV-2 was determined by ELISA using a set of reagents for analyzing human serum or plasma for the presence of specific immunoglobulins of class G to the nucleocapsid of the SARS-CoV-2 virus produced by the FBUN GNCPMiB Rospotrebnadzor (Obolensk) in accordance with the instructions for application. Results. The level of population immunity in the Murmansk region as a whole was 31,2%. The highest seroprevalence was found among children aged 1–6 and 7–13 years (35.6% and 44,1%, respectively), the lowest among the elderly population aged 60–69, as well as 70 and more years (20,4% and 20,9%, respectively). In the cities of the Murmansk region. the herd level of immunity varied from 19,6% (Kola city) to 46,1% (Kandalaksha city). It was not possible to find a reliable relationship between the incidence of the population of the cities of the Murmansk region and seroprevalence. The highest level of seroprevalence was noted among office workers (38,0%), the lowest among transport workers (19,5%). In the presence of contacts with patients with COVID-19, seropositivity increased 1,4 times compared to the average population value. The level of specific humoral immunity in convalescents after COVID-19 is 64,1%, which is 2,2 times higher than the average for half-day. The proportion of asymptomatic forms among seroprevalence volunteers was 89%. © 2021. All Rights Reserved.
ABSTRACT
In late 2019, there were reports of an outbreak of infection caused by a new strain of beta coronavirus SARSCoV-2, the WHO identified the disease as coronavirus disease 2019 (COVID-19). In Tatarstan, the first case of COVID-19 was diagnosed on March 16, 2020, it was an imported case from France. The period of increase in the incidence lasted during the 12th to the 19th week, when the highest rate was recorded, amounting to 16.7 per 100 thousand population. Subsequently, a statistically significant decrease in the incidence was noted. Seroprevalence study was conducted at week 27 (8th week of decline of morbidity).The purpose of the seroepidemiological study was to measure the level and to identify the structure of herd immunity against the SARS-CoV-2 virus among the population of the Republic of Tatarstan during the rapid spread of the COVID-19 outbreak.Materials and methods. The selection of volunteers for the study was carried out by the method of questionnaires and randomization by random sampling. The exclusion criterion was active COVID-19 infection at the time of the survey. 2,946 people were examined for the presence of specific antibodies to SARS-CoV-2. The age of the surveyed volunteers ranged from 1 year to 70 years and older.Results. The results of the study showed that in the Republic of Tatarstan during the period of COVID-19 incidence, there was a moderate seroprevalence to SARS-CoV-2, which amounted to 31.3%, against the background of a high frequency (94.5%) of asymptomatic infection in seropositive individuals who did not have a history of past COVID-19 disease, positive PCR result and ARVI symptoms on the day of the examination. The maximum indicators of herd immunity were established in children aged 7-13 years (42.0%), children 14-17 years old (40.3%), with a simultaneous decrease in seroprevalence in persons aged 70 and older (24.0%). In different regions of the Republic of Tatarstan, there was a wide variation in seropositivity results from the minimum in the Zainsky district (8.6%) to the maximum in the Arsky district (74.3%). In 21 out of 38 surveyed districts, the results were unrepresentative due to the small sample size. In COVID-19 convalescents, antibodies are produced in 83.3% of cases. In persons with a positive result of the PCR analysis carried out earlier, antibodies were detected in 100% of cases. Among the volunteers who had contact with patients with COVID-19, the proportion of seropositive is 37%Conclusion. The dynamics of seroprevalence among the population of the Republic of Tatarstan can be qualified as positive, the results obtained can be used to develop a forecast for the development of the epidemiological situation, as well as to plan measures for specific and non-specific prevention of COVID-19. В конце 2019 г. появились сообщения о вспышке инфекции, вызванной новым штаммом beta-коронавируса SARS-CoV-2, заболевание ВОЗ определила как coronavirus disease 2019 (COVID-19). В Республике Татарстране первый случай COVID-19 был диагностирован 16.03.2020 г., это был завозной случай из Франции. Период нарастания заболеваемости продолжался с 12-й по 19-ю неделю, когда был зарегистрирован самый высокий показатель, составивший 16,7 на 100 тыс. населения. В дальнейшем отмечалось статистически значимое снижение заболеваемости. Исследование серопревалентности было проведено на 27-й неделе (8-я неделя снижения заболеваемости)Целью проведенного сероэпидемиологического исследования было определение уровня и структуры популяционного иммунитета к вирусу SARS-CoV-2 среди населения Республики Татарстан в период распространения COVID-19.Материалы и методы. Отбор волонтеров для исследования проводили методом анкетирования и рандомизации путем случайной выборки. Критерием исключения была активная инфекция COVID-19 в момент анкетирования. На наличие специфических антител к SARS-CoV-2 обследовано 2946 человек. Возраст обследованных добровольцев варьировал от 1 года до 70 лет и старше.Результаты. Результаты исследования показали, что в Республике Татарстан в период заболеваемости COVID-19 наблюдалась умеренная серопревалентность к SARS-CoV-2, составившая 31,3%, на фоне высокой частоты (94,5%) бессимптомной инфекции у серопозитивных лиц, не имевших в анамнезе перенесенного заболевания COVID-19, положительного результата ПЦР и симптомов ОРВИ в день обследования. Максимальные показатели коллективного иммунитета установлены у детей 7-13 лет (42,0%), детей 14-17 лет (40,3%) при одновременном снижении серопревалентности у лиц в возрасте 70 лет и старше (24,0%). В разных регионах Республики Татарстан наблюдалось широкое варьирование показателей серопозитивности от минимального в Заинском районе (8,6%) до максимального в Арском районе (74,3%). В 21 районе из 38 обследованных результаты были нерепрезентативны из-за малого числа наблюдений. У реконвалесцентов COVID-19 антитела вырабатываются в 83,3% случаев. У лиц с позитивным результатом ПЦР-анализа, проведенного ранее, антитела выявлялись в 100% случаев. Среди волонтеров, имевших контакты с больными COVID-19, доля серопревалентных 37%.Вывод. Динамику серопревалентности среди населения Республики Татарстан можно квалифицировать как позитивную. Полученные результаты могут быть использованы для разработки прогноза развития эпидемиологической ситуации, а также планирования мероприятий по специфической и неспецифической профилактике COVID-19.
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The article presents data on the features of COVID-19 infection in patients with primary immunodeficiencies (PIDs) in the Russian Federation, obtained through the National association of experts in PID (NAEPID) registry. Materials and methods: from March 1, 2020 to October 15, 2020, 15 cases of close intrafamilial contact between PIDs patients and COVID-19 patients without reliable infection of the first and 23 cases of COVID-19 infection in PIDs patients were reported. Results: 6/23 infected people had asymptomatic course of infection, 9/23 patients - mild form, 8/23 -moderate form of disease, one patient had a severe course with a fatal outcome. 19/23 patients were under 18 years of age, which corresponds with the age data of the national Russia PID registry. Conclusion: perhaps this age composition partially explains the milder course of COVID-19 in PIDs patients compared to the European data. Other possible reasons for a milder course may be the lower pathogenicity of the coronavirus strain circulating in the Russian Federation. В статье представлены данные об особенностях течения COVID-19 у пациентов с первичными иммунодефицитами (ПИД) в РФ, собранные с помощью регистра Национальной ассоциации экспертов в области ПИД (НАЭПИД). Материалы и методы исследования: всего с 1 марта 2020 г. по 15 октября 2020 г. было репортировано 15 случаев тесного внутрисемейного контакта между пациентами с ПИД и больными COVID-19 без достоверного инфицирования первых и 23 случая инфицирования COVID-19 у пациентов с ПИД. Результаты: 6/23 инфицированных перенесли инфекцию бессимптомно, 9/23 - в легкой, 8/23 - в среднетяжелой форме, у одного пациента - тяжелое течение с летальным исходом. 19/23 пациентов были младше 18 лет, что коррелирует с данными национального регистра ПИД в РФ. Заключение: возможно, такое возрастное распределение частично объясняет более легкое течение COVID-19 у пациентов с ПИД по сравнению с европейскими данными. Другими возможными причинами, обусловливающими более легкое течение, могут быть меньшая патогенность штамма коронавируса, циркулирующего на территории РФ.
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Introduction. The COVID-19 pandemic was announced by WHO in February 2020. In the Kaliningrad region, the first case (imported) was registered in early March 2020, the beginning of the epidemic increase fell on the 14th week. 2020, and the peak incidence was reached in the 22nd week of the year, after which there was a steady decrease in the number of cases. The study of population immunity was carried out at the 32nd week during the period of the lowest level of intensity of the epidemic process. Purpose of the study. Assessment of the assessment of the level of population immunity to the SARS-CoV-2 virus among the population of the Kaliningrad region during the period of the epidemic incidence of the population of COVID-19. Materials and methods. The study was carried out as part of the first stage of the Rospotrebnadzor program to assess population immunity to SARS-CoV-2 among the population of the Russian Federation. The selection of volunteers for the study was carried out by a questionnaire survey and subsequent randomization. The analysis includes the results of a survey of 2675 people. The number of volunteers in age groups ranged from 314 to 493 people. The results obtained were processed by the methods of variation statistics. Results. The results obtained showed that the average seroprevalence in the population was 50.2%, while the highest seroprevalence was found in the child age group 1-17 years (66.9%) and among persons aged 18-29 (57.0). No significant gender differences were found (men – 48,3 ± 1,6%, women – 51,1 ± 1,1%). The distribution of the proportion of seropositive people in the settlements of the region varied from 33,9% to 59.6%. The largest share of seroprevalence in the representative samples was found among people engaged in art / creativity (55,3%), the smallest – among educational workers (42,0%). Among COVID-19 convalescents, the level of humoral immunity reached 94,6%. Most of the seropositive volunteers (95,2%) did not have any symptoms of COVID-19, that is, they belonged to the category of asymptomatic carriers. Output. The results of a survey of a representative cohort of volunteers in the Kaliningrad region showed that they are characterized by a high level of population immunity, which makes it possible to expect a decrease in. © 2021 Interregional public organization Association of infectious disease specialists of Saint-Petersburg and Leningrad region (IPO AIDSSPbR). All rights reserved.
ABSTRACT
The first case of COVID-19 was registered in the Leningrad Region on March 13, 2020. The period of increasing intensity of the epidemic process lasted 8 weeks. One month after reaching the maximum incidence rate, a study was organized to determine seroprevalence to COVID-19 among the population of the Region. Objective of the study was to determine the level and structure of community immunity to SARS-CoV-2 virus in the population of the Leningrad Region in the period of intensive COVID-19 transmission. Materials and methods. The work was carried out within the framework of the Rospotrebnadzor project on assessment of community immunity to the SARS-CoV-2 virus in the population of the Russian Federation. The content of antibodies to SARS-CoV-2 was determined applying ELISA using a kit for the analysis of human serum or blood plasma for the presence of specific IgG to the nucleocapsid of the SARS-CoV-2 virus, manufactured by the State Scientific Center of Applied Microbiology and Biotechnology (Obolensk) in accordance with the instructions for use. Results and discussion. The study has showed that the herd immunity of the population of the Leningrad Region was 20.7 %. The maximum level has been established in children 1–6 years old (42.3 %) and people over 70 years old (29.0 %). The highest level of seropositivity, except for children and older people, was found among the unemployed (25.1 %). The lowest level of seroprevalence was detected in civil servants (12.8 %) and military personnel (16.7 %). It has been shown that the risk of infection increases by 1.5 times in case of contacts with COVID-19 patients. After exposure to COVID-19 virus, antibodies are produced in 82.1 % of the cases. In individuals with a positive PCR test result obtained earlier, antibodies are detected in 82.8 % of cases. The share of asymptomatic forms among seropositive residents of the Leningrad Region was 86.9 %. The results of assessing the herd immunity to SARS-CoV-2 in the population of the Leningrad Region indicate that during the period of intensive COVID-19 transmission, an average level of seroprevalence was formed. A significant proportion of asymptomatic forms of infection characterizes the high intensity of the latently developing epidemic process. The results obtained should be taken into account when organizing preventive measures, including vaccination, and predicting morbidity rates. © 2020 Russian Research Anti-Plague Institute. All rights reserved.