Structure of herd immunity to SARS-COV-2 in the Krasnoyarsk region population in the COVID-19 epidemic

Purpose. Determination of the SARS-CoV-2 population humoral immunity among the population of the Krasnoyarsk Territory during the COVID-19 epidemic.Materials and methods. The study was carried out as a part of project for 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 revealed any peculiarities throughout the study. The trend towards a decrease in the incidence was formed on the 6th week of 2021. The seroprevalence of convalescents 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.

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Humoral immunity to SARS-CoV-2 among the population of Murmansk region amid COVID-19 epidemic

HIV Infection and Immunosuppressive Disorders ◽

10.22328/2077-9828-2021-13-1-17-27 ◽

2021 ◽

Vol 13 (1) ◽

pp. 17-27

Author(s):

A. Yu. Popova ◽

E. B. Ezhlova ◽

A. A. Melnikova ◽

L. A. Lukicheva ◽

N. I. Nikitina ◽

...

Keyword(s):

Humoral Immunity ◽

Elderly Population ◽

Age Groups ◽

The Elderly ◽

Population Immunity ◽

Murmansk Region ◽

Structure Of Population ◽

Transport Workers ◽

Unified Method

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%.

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Collective immunity to SARS-CoV-2 of Moscow residents during the COVID-19 epidemic period

Infekcionnye bolezni ◽

10.20953/1729-9225-2020-4-8-16 ◽

2020 ◽

Vol 18 (4) ◽

pp. 8-16

Author(s):

A.Yu. Popova ◽

◽

E.B. Yezhlova ◽

A.A. Melnikova ◽

E.E. Andreeva ◽

...

Keyword(s):

Herd Immunity ◽

Age Groups ◽

Asymptomatic Infection ◽

Administrative District ◽

Cultural Workers ◽

Population Immunity ◽

The North ◽

First Case ◽

Epidemic Period ◽

Structure Of Population

The coronavirus disease pandemic (COVID-19) was announced by WHO in February 2020. In Moscow, the first case of the disease was detected on March 2, 2020 in a man who arrived from Italy. Two weeks after the first case, there was an exponential increase in the number of cases. The incidence peaked in the 19th week of the year, followed by a steady decline, lasting 16 weeks. Objective. To investigate the level and structure of population immunity to the SARS-CoV-2 virus among the population of Moscow against the background of the incidence of COVID-19. Patients and methods. The study of population immunity of Moscow residents to SARS-CoV-2 was carried out in the period from July 1, 2020 to July 30, 2020 against the background of stabilization of the incidence rate. The work was conducted as part of the first stage of the Rospotrebnadzor project to assess population immunity to the SARS-CoV-2 virus among the population of the Russian Federation, taking into account the protocol recommended by WHO. Volunteers for the study were selected by the method of questioning and randomization. The results of the survey of 2688 people were included in the analysis. The number of volunteers in all age groups was 384–385 people. The content of specific IgG to the SARS-CoV-2 nucleocapsid was determined by the enzyme-linked immunosorbent assya using a kit produced by FBIS SRCAMB according to the manufacturer's instructions. Results. During the survey of volunteers it was found that the share of seroprevalent residents of Moscow was 22.1%. By age groups, the highest proportion of seroprevalent was found among children aged 14–17 years (44.6%), the lowest (15.9%) – among people aged 18–29 years. Seroprevalence had no gender differences. The lowest level of herd immunity was revealed in the North-Western Administrative District (16.8%), the highest – in the South-Eastern Administrative District, as well as in the Troitsky and Novomoskovsky Administrative Districts of Moscow (in both, 24.1%). The smallest number of seropositive persons was among cultural workers (5.8%), the largest – among medical workers (27.0%). In the presence of contacts with patients with COVID-19, the probability of seroconversion increases by 1.5 times, and among convalescing persons COVID-19 antibodies were detected in 60.0% of cases. The proportion of people with asymptomatic infection among seropositive residents was 82.4%. Conclusion. The results obtained make it possible to characterize the population immunity of Moscow residents and are essential for the planning and implementation of anti-epidemic measures during the incidence of COVID-19. Key words: coronaviruses, SARS-CoV-2, seroprevalence, population, COVID-19

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Herd immunity to SARS-COV-2 in the population of the Southern regions of the Far East of Russia

Acta biomedica scientifica ◽

10.29413/abs.2021-6.5.25 ◽

2021 ◽

Vol 6 (5) ◽

pp. 253-273

Author(s):

A. Yu. Popova ◽

V. S. Smirnov ◽

E. B. Ezhlova ◽

A. A. Melnikova ◽

O. E. Trotsenko ◽

...

Keyword(s):

Statistical Significance ◽

Herd Immunity ◽

Far East ◽

Amur Region ◽

Reproductive Number ◽

Pasteur Institute ◽

Scientific Center ◽

Cross Sectional ◽

Population Immunity ◽

The Far East

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 initial cross-sectional study, 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-yearolds 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 described by a second-order polynomial. A relationship 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.

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PECULIARITIES OF SARS-COV-2 NUCLEOCAPSID IN CHILDREN DURING THE COVID-19 EPIDEMIC OF 2020

PEDIATRIA Journal named after G N SPERANSKY ◽

10.24110/0031-403x-2021-100-3-97-106 ◽

2021 ◽

Vol 100 (3) ◽

pp. 97-106

Author(s):

A.Yu. Popova ◽

◽

E.E. Andreeva ◽

E.A. Babura ◽

S.V. Balakhonov ◽

...

Keyword(s):

Russian Federation ◽

Venous Blood ◽

Age Groups ◽

Enzyme Linked Immunosorbent Assay ◽

Continuous Growth ◽

Epidemic Process ◽

Three Stages ◽

The Russian Federation ◽

Comparative Determination

The aim of the study is to summarize the results of a study of seroprevalence of children to SARS-CoV-3, obtained during the implementation of the Rospotrebnadzor program to assess seroprevalence to the NC antigen SARS-CoV-2 of the population of 26 regions of the Russian Federation, conducted during the COVID-19 epidemic in 2020. Research methods: the study of seroprevalence in 26 model territories of the Russian Federation was carried out according to a unified methodology developed by Rospotrebnadzor with the participation of the St. Petersburg Pasteur Institute of Epidemiology and Microbiology. The method provided for the formation of a group of volunteers in a model federative entity, including children aged 1–17 years, in which the presence of antibodies to the SARS-CoV-2 nucleocapsid was determined in venous blood plasma by the enzyme-linked immunosorbent assay (ELISA). The examination of volunteers was carried out in 3 stages: June-August, September-October, December. Results: the study found that in most of the areas surveyed, children had a higher level of seroprevalence than adults. It is shown that high seroprevalence is accompanied by statistically significant decrease in morbidity (p0.05). The analysis of seroprevalence at all three stages revealed at least 3 variants of its dynamics: 1) continuous growth of seroprevalence in parallel with the development of the epidemic process; 2) an episodic change in the periods of increase and decrease in the level of seroprevalence; 3) a continuous decrease in seroprevalence at the level of the epidemic process. Comparative determination of seroconversion levels in three age groups – 1–6, 7–13 and 14–17 years – revealed no statistically significant differences between these age groups have been identified. Conclusion: children aged 1–17 years in most of the surveyed territories of the Russian Federation have a higher seroprevalence to SARS-CoV2 than adults. The increase in seroprevalence in children is accompanied by a decrease in the incidence of COVID-19.

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Manifestations of the Epidemic Process of Measles and Rubella at the Present Stage

Epidemiology and Vaccinal Prevention ◽

10.31631/2073-3046-2018-17-5-45-53 ◽

2018 ◽

Vol 17 (5) ◽

pp. 45-53 ◽

Cited By ~ 3

Author(s):

A. A. Pozdnyakov ◽

O. P. Chernyavskaya

Keyword(s):

Statistical Significance ◽

Age Groups ◽

Present Stage ◽

Microsoft Excel ◽

Epidemic Process ◽

Contact Number ◽

Population Immunity ◽

Younger Age ◽

Rate Of Decline ◽

Short Time

Relevance.Measles and rubella have been known to humanity for centuries. These two infections have a number of similarities. However, despite all the similarities and a single elimination program, it is not possible to achieve the same results by the level of the incidence of these infections. Goal. Identify common features and differences in the manifestations of the epidemic process of measles and rubella at the present stage and formulate a hypothesis on their explanation.Materials and methods. Methods of retrospective epidemiological analysis of morbidity were used: Evaluation of the statistical significance of the differences in indicators with the Student’s test. To compare the rate of decrease in the incidence of measles and rubella their exponential approximations using the method of least squares were used. To process the research data, the Microsoft Excel program was used.Results.In the pre-vaccination period, the incidence of measles was 4.6 times higher than rubella. For major infections in this period characterized by a pronounced cyclic morbidity, while the intervals between cyclical rises for measles are shorter, and the amplitude of cycles is higher. As the population was vaccinated, the incidence of these infections decreased, while the rate of decline in the incidence of rubella was higher than that of measles. Also, a faster decrease in morbidity and smoothing of the cyclicity, a transition to older age groups, a gradual exit from the incidence of younger age groups confirm that the rubella has a contact number less then measles.Conclusion.The current level of population immunity is sufficient to eliminate rubella in a relatively short time. For measles, which has greater contagiousness and a contact number, and is more demanding for population immunity, this level is not enough. As a consequence, rubella shows better «manageability» in immunization than measles.

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Assessment of Population Immunity to SARS-CoV-2 Virus in the Rostov Region

Problems of Particularly Dangerous Infections ◽

10.21055/0370-1069-2020-4-117-124 ◽

2021 ◽

pp. 117-124

Author(s):

A. Yu. Popova ◽

E. B. Ezhlova ◽

A. A. Mel’nikova ◽

A. K. Noskov ◽

E. V. Kovalev ◽

...

Keyword(s):

Herd Immunity ◽

Age Groups ◽

Incidence Rates ◽

The State ◽

Scientific Center ◽

Education Professionals ◽

Humoral Immune ◽

Population Immunity ◽

Rostov Region ◽

High Level

By August 2020, more than 850000 cases of new coronavirus infection (COVID-19) caused by SARSCoV-2 were confirmed in the Russian Federation, with the Rostov Region as one of the ten most affected regions in Russia. The spread of the disease is largely determined by the state of population immunity in a certain area. Our research focuses on specific humoral immune response and estimates the level of herd immunity to SARS-CoV-2 virus among the population of the Rostov Region.Materials and methods. The study involved 3,048 people; the volunteers participating in the study were divided into seven age groups. 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 assessment of seroprevalence to SARS-CoV-2 in the Rostov Region showed that the proportion of people positive for IgG to the new coronavirus was 16.5 %, the range of seropositive individuals in the general population was between 13.9 % and 19.1 % (p<0.05). There were no significant gender differences in the degree of seroprevalence with a positive result registered in 16.6 % of women and 16.5 % of men. A high level of humoral immunity to SARS-CoV-2 was established in individuals aged 1–17 against the background of low incidence rates, which may indicate the dominance of asymptomatic forms of the disease in this age group. The highest level of seropositivity was found in preschool children (33.6 %), students (29.3 %), employees (17.3 %), and education professionals (15.3 %).

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Characteristic of herd immunity among the population of Stavropol region amid the COVID-19 epidemic

Journal Infectology ◽

10.22625/2072-6732-2021-13-4-79-89 ◽

2021 ◽

Vol 13 (4) ◽

pp. 79-89

Author(s):

A. Yu. Popova ◽

E. B. Ezhlova ◽

A. A. Melnikova ◽

V. S. Smirnov ◽

L. V. Lyalina ◽

...

Keyword(s):

Herd Immunity ◽

Age Groups ◽

Population Level ◽

Fold Increase ◽

Disease Spread ◽

Steady Increase ◽

Epidemic Process ◽

Population Immunity ◽

First Case ◽

Asymptomatic Volunteers

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 COVID-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.

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Influence of age and sex on certain serum biochemical parameters of dromedary camels

Nova Journal of Medical and Biological Sciences ◽

10.20286/jmbs-050304 ◽

2016 ◽

Vol 5 (3) ◽

Author(s):

Nawal Mohamed Elkhair

Keyword(s):

Reference Values ◽

Adult Male ◽

Biochemical Parameters ◽

Reference Range ◽

Venous Blood ◽

Age Groups ◽

Serum Biochemical Parameters ◽

Serum Biochemical ◽

Strong Electrolytes

Background: The identification of the reference values of certain serum biochemical parameters in relation to the age was studied in dromedary camels.Methods: Fourteen healthy young camels (age: 3-5 months), 12 adult male and 10 female camels (age: 5-8 years) were used. Venous blood samples were collected for the determination of certain serum parameters.Results: The reference range ( ± s×1.96) of serum- [Na+] was 142-160 mmol/l and the percentile range (median (1. - 3.Quartile)) was 143-156 mmol/l for all age groups. The reference values of serum- [K+] showed a significant (P<0.05) variation between the age groups being higher the young camels (4.2-7.4 mmol/l) compared to the adult groups (3.7-5.5 mmol/l). Serum- [Protein] and serum- [Albumin] showed significant (P<0.05) differences between the age groups. Significantly higher (P<0.05) reference range of 51-74 g/l and a percentile range of 59-67.7 g/l was observed in the adult female camels compared to young and adult male groups.Conclusion: These reference values are useful in detecting the influence of strong electrolytes such as Na+, K+ and Cl- and weak acids (proteins) on the physiological and pathological status of the camels in relation to their age.Keywords: Camels, age, electrolyte concentrations, total protein, albumin, reference values.

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A Prospective Multicenter Randomized Study State of Humoral Immunity after a New Coronavirus Infection (COVID-19) of a Mild or Asymptomatic Course

Annals of the Russian academy of medical sciences ◽

10.15690/vramn1582 ◽

2021 ◽

Vol 76 (4) ◽

pp. 361-367

Author(s):

Evgeniy V. Kryukov ◽

Dmitriy V. Trishkin ◽

Vladimir V. Salukhov ◽

Pavel S. Sadovnikov ◽

Yuriy V. Andreychuk ◽

...

Keyword(s):

Humoral Immunity ◽

Neutralizing Antibodies ◽

Randomized Study ◽

Venous Blood ◽

Age Groups ◽

High Morbidity ◽

Positive Polymerase Chain Reaction ◽

S Protein ◽

Laboratory Service ◽

Coronavirus Infection

Background.The rapid spread of COVID-19 in the world, the severity of disease, high morbidity and mortality have rightly made the COVID-19 pandemic a major threat to humanity. Therefore, one of the most urgent problems for practical health care is the issue of development of immunity for COVID-19 survivors, the possibility of re-infection, and the appropriateness of vaccination. The article presents the interim results of the study was named RESPONSE devoted to assessing the immunity for 90 days from patients that survived COVID-19 in a mild or asymptomatic course. Aims to study of the dynamics of generation of SARS-CoV-2 adhesive (S) protein neutralizing antibodies (IgG) and specificities of humoral immunity from COVID-19 survivors with light and asymptomatic form of disease in depending on gender and age. Materials and methods.Joint study by the Military Medical Academy n.a. S.M. Kirov and Laboratory Service Helix is being undertaken in the period from January 06, 2020 to August 1, 2021 on the basis of Academy clinics and Helix diagnostic centers in Saint Petersburg. The study was included 1109 males and females aged 18 to 70 (average age 38.2), who received to outpatient treatment of light and asymptomatic form of New Coronavirus Infection. All patients included in the investigation were done survey of quantitative neutralizing antibodies of class IgG to S-protein SARS-CoV-2 content in venous blood in 30, 45, 60 and 90 days from the last result of positive polymerase chain reaction with reverse transcription (OT-PCR) for determining nucleic acid SARS-CoV-2 in biological material by immunochemiluminescent analysis (LIAISON XL, DiaSorin S.p.A., made in Italy). Results.The IgG class antibody to the S-protein SARS-CoV-2 were not diagnosed 30 days after the survived infection only 0.9% of young women (1844 years) and 0.8% of men in the same age bracket. In other age groups, antibodies were defined in all participants of study. Titer of IgG gradually increases to peak concentration after 45 days, its kept at this level to the 60th day, and then it has a decreasing trend after 90 days from the onset of the disease. Conclusions.The results show the timing of generation and duration of the humoral response in survived patients COVID-19 in a mild or asymptomatic form. For 45 days, antibodies were determined in all participants of the study, reflecting the development of post-infectious humoral immunity, which was maintained in patients with the mild or asymptomatic forms of COVID-19 at least 3 months.

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Herd immunity of sars-cov-2 among the population of Kalinigrad region amid the COVID-19 epidemic

Journal Infectology ◽

10.22625/2072-6732-2020-12-5-62-71 ◽

2021 ◽

Vol 12 (5) ◽

pp. 62-71

Author(s):

A. Yu. Popova ◽

E. B. Ezhlova ◽

A. A. Melnikova ◽

E. A. Babura ◽

O. P. Mikheenko ◽

...

Keyword(s):

Herd Immunity ◽

Age Groups ◽

Population Immunity ◽

First Case ◽

The Russian Federation ◽

Kaliningrad Region ◽

High Level ◽

Representative Cohort ◽

Representative Samples ◽

Selection Of

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.

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