scholarly journals SARS-CoV-2 Seroprevalence Structure of the Russian Population during the COVID-19 Pandemic

Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1648 ◽  
Author(s):  
Anna Y. Popova ◽  
Viacheslav S. Smirnov ◽  
Elena E. Andreeva ◽  
Elena A. Babura ◽  
Sergey V. Balakhonov ◽  
...  
Keyword(s):  
Herd Immunity ◽  
Population Sample ◽  
Age Groups ◽  
Phase Curve ◽  
Initial Increase ◽  
Two Phase ◽  
Scientific Center ◽  
Continuous Increase ◽  
Rate Of Increase ◽  
Federal Districts

The SARS-CoV-2 pandemic, which came to Russia in March 2020, is accompanied by morbidity level changes and can be tracked using serological monitoring of a representative population sample from Federal Districts (FDs) and individual regions. In a longitudinal cohort study conducted in 26 model regions of Russia, distributed across all FDs, we investigated the distribution and cumulative proportions of individuals with antibodies (Abs) to the SARS-CoV-2 nucleocapsid antigen (Ag), in the period from June to December 2020, using a three-phase monitoring process. In addition, during the formation of the cohort of volunteers, the number of seropositive convalescents, persons who had contact with patients or COVID-19 convalescents, and the prevalence of asymptomatic forms of infection among seropositive volunteers were determined. According to a uniform methodology, 3 mL of blood was taken from the examined individuals, and plasma was separated, from which the presence of Abs to nucleocapsid Ag was determined on a Thermo Scientific Multiascan FC device using the “ELISA anti-SARS-CoV-2 IgG” reagent set (prod. Scientific Center for Applied Microbiology and Biotechnology), in accordance with the developer’s instructions. Volunteers (74,158) were surveyed and divided into seven age groups (1–17, 18–29, 30–39, 40–49, 59–59, 60–69, and 70+ years old), among whom 14,275 were identified as having antibodies to SARS-CoV-2. The average percent seropositive in Russia was 17.8% (IQR: 8.8–23.2). The largest proportion was found among children under 17 years old (21.6% (IQR: 13.1–31.7). In the remaining groups, seroprevalence ranged from 15.6% (IQR: 8–21.1) to 18.0% (IQR: 13.4–22.6). During monitoring, three (immune) response groups were found: (A) groups with a continuous increase in the proportion of seropositive; (B) those with a slow rate of increase in seroprevalence; and (C) those with a two-phase curve, wherein the initial increase was replaced by a decrease in the percentage of seropositive individuals. A significant correlation was revealed between the number of COVID-19 convalescents and contact persons, and between the number of contacts and healthy seropositive volunteers. Among the seropositive volunteers, more than 93.6% (IQR: 87.1–94.9) were asymptomatic. The results show that the COVID-19 pandemic is accompanied by an increase in seroprevalence, which may be important for the formation of herd immunity.

scholarly journals Characteristics of the Herd Immunity to SARS-CoV-2 in Residents of the Saratov Region under COVID-19 Epidemic

2021 ◽  
pp. 106-116
Author(s):  
A. Yu. Popova ◽  
E. B. Ezhlova ◽  
A. A. Mel’nikova ◽  
V. V. Kutyrev ◽  
O. I. Kozhanova ◽  
...  
Keyword(s):  
Clinical Symptoms ◽  
Herd Immunity ◽  
Age Groups ◽  
Pcr Analysis ◽  
Maximum Increase ◽  
Scientific Center ◽  
Saratov Region ◽  
Infected People ◽  
First Case ◽  
Coronavirus Infection

The global community is experiencing one of the largest infectious disease outbreaks in the 21st century. In the Saratov Region, the first case of new coronavirus infection was confirmed on March 19, 2020.The maximum increase in cases was noted between May 15 and June 30, during that time the total number of infected people in the region increased from 1526 to 6444. Since July 2020, a stable incidence level of new coronavirus infection has been observed in the Saratov Region, without a steady decline.The aim of the study was to assess the status of population immunity to the SARS-CoV-2 virus among residents of Saratov and the Saratov Region under the COVID-19 epidemic.Materials and methods. In the period from June 23 to July 26, 2020, a serological study of blood samples from 3372 volunteers of different age groups was conducted. The content of antibodies to SARS-CoV-2 was determined by ELISA using a set of reagents “ELISA anti-SARS-CoV-2 IgG” produced by the State Scientific Center of Applied Microbiology and Biotechnology of the Rospotrebnadzor (Russia).Results and discussion. In general, the incidence of COVID-19 in the Saratov Region is taking place against the background of moderate seroprevalence to the SARS-CoV-2 virus, accompanied by a high incidence of non-apparent (asymptomatic) forms of the infectious process. The absence of clinical symptoms of the disease, in the context of the limited use of methods for determining the RNA of the SARS-CoV-2 virus in PCR (11 % of the region’s population) makes it difficult to assess the real spread of the virus in the population and to establish the timing of the formation of persistent herd immunity. A low rate of antibody response among individuals with a positive result of PCR analysis, as well as among volunteers who had an infection in May, June 2020, indicates a weak formation of the immune response, or the prevalence of individuals reacting mainly by activating the cellular link of the immune system in the population. The obtained results, although they need to be explained in a number of respects, can be applied to the organization of preventive measures, including vaccination, in the region. 

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

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 %). 

scholarly journals Why ODE models for COVID-19 fail: Heterogeneity shapes epidemic dynamics

2021 ◽  
Author(s):  
Gerrit Großmann ◽  
Michael Backenköhler ◽  
Verena Wolf
Keyword(s):  
Viral Load ◽  
Herd Immunity ◽  
Age Groups ◽  
Stochastic Simulations ◽  
Contact Network ◽  
Initial Increase ◽  
Epidemic Dynamics ◽  
Ode Models ◽  
Point Estimates ◽  
Model Complex

AbstractIn the recent COVID-19 pandemic, mathematical modeling constitutes an important tool to evaluate the prospective effectiveness of non-pharmaceutical interventions (NPIs) and to guide policy-making. Most research is, however, centered around characterizing the epidemic based on point estimates like the average infectiousness or the average number of contacts.In this work, we use stochastic simulations to investigate the consequences of a population’s heterogeneity regarding connectivity and individual viral load levels.Therefore, we translate a COVID-19 ODE model to a stochastic multi-agent system. We use contact networks to model complex interaction structures and a probabilistic infection rate to model individual viral load variation.We observe a large dependency of the dispersion and dynamical evolution on the population’s heterogeneity that is not adequately captured by point estimates, for instance, used in ODE models. In particular, models that assume the same clinical and transmission parameters may lead to different conclusions, depending on different types of heterogeneity in the population. For instance, the existence of hubs in the contact network leads to an initial increase of dispersion and the effective reproduction number, but to a lower herd immunity threshold (HIT) compared to homogeneous populations or a population where the heterogeneity stems solely from individual infectivity variations.Author summaryComputational modeling can support decision-making in the face of pandemics like COVID-19. Models help to understand transmission data and predict important epidemiological properties (e.g., When will herd immunity be reached?). They can also examine the effectiveness of certain measures, and—to a limited extent—extrapolate the dynamics under specific assumptions. In all these cases, the heterogeneity of the population plays an important role. For instance, it is known that connectivity differences in (and among) age groups influence the dynamics of epidemic propagation. Here we focus on two types of differences among individuals: their social interactions and on how infectious they are. We show that only considering population averages (e.g., What is the average number of contacts of an individual?) may lead to misleading conclusions, because the individual differences (such as those related to the epidemic (over-)dispersion) play an important role in shaping the epidemic dynamics. Many commonly used model classes, such as SEIR-type ODE compartmental models, ignore differences within a population to a large extent. This omission bears the potential of misleading conclusions.

scholarly journals Serological surveillance of noroviruses in a community-based prospective cohort: a study protocol

BMJ Open ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. e043228
Author(s):  
Lu Wang ◽  
Dongjie Xie ◽  
Jingrong Yu ◽  
Mark Momoh Koroma ◽  
Mengsi Qiu ◽  
...  
Keyword(s):  
Prospective Cohort ◽  
Herd Immunity ◽  
Age Groups ◽  
Northern China ◽  
Oil Field ◽  
Blood Collection ◽  
Sociodemographic Characteristics ◽  
Blood Group Antigens ◽  
Community Based ◽  
Serological Surveillance

IntroductionNoroviruses are the leading cause of viral acute gastroenteritis affecting all age groups. Since 2014, the previous rarely reported GII.P17-GII.17 and recombinant GII.P16-GII.2 norovirus emerged, replacing GII.4 predominant genotype, causing increased outbreaks in China and other countries. Meanwhile, GII.4/2012 Sydney strain has re-emerged as the dominant variant in many places in 2015–2018. The role of herd immunity as the driving force during these new emerging or re-emerging noroviruses is poorly defined. Serological surveillance studies on community-based prospective cohort on norovirus are highly needed.Methods and analysesThis study will include 1000 out of 9798 participants aged 18 years and above from Caofeidian district, Tangshan city, northern China. Baseline data on sociodemographic characteristics and blood samples were collected in 2013–2014. Blood collection will be replicated annually throughout the cohort until 2023. Saliva samples were also collected in 2016. The seroprevalence and seroincidence of blockade antibodies against norovirus genotypes of GII.P17-GII.17, GII.P16-GII.2, the re-emerged GII.4/2012 and potential novel pandemic variants will be evaluated by ELISA. Associations between genotype blockade antibodies and sociodemographic factors and human histo-blood group antigens will be evaluated using univariate and multivariate analysis. The dynamics of herd immunity duration will be estimated in this longitudinal surveillance.Ethics and disseminationThe study has been approved by the Ethical Committees of the Staff Hospital of Jidong oil-field of China National Petroleum Corporation. This study will provide insight into the seroprevalence and seroincidence of noroviruses, and their relationships with sociodemographic characteristics and genetic susceptibility. It will also explain herd immunity of the emerged and re-emerged genotypes or variants. The study will further enable an understanding of the mechanism driving the replacement of norovirus genotypes. Research findings will be disseminated in peer-reviewed journals and at scientific meetings.

scholarly journals Age-Cohort Differences in Longitudinal Associations Between the Rate of Internet Use and Memory Functioning

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 410-410
Author(s):  
Vineet Raichur ◽  
Lindsay Ryan ◽  
Richard Gonzalez ◽  
Jacqui Smith
Keyword(s):  
Older Adults ◽  
Episodic Memory ◽  
Cognitive Complexity ◽  
Internet Use ◽  
Age Groups ◽  
Word Recall ◽  
Use Patterns ◽  
Younger Age ◽  
Rate Of Increase ◽  
Over Time

Abstract Cross-sectional analyses of internet use patterns among older adults find that the rate of internet use is less with greater physical and memory difficulties. It is not clear, however, how age-cohorts differ in their internet use as physical and memory difficulties increase over time. In addition to factors such as increasing accessibility (cost) and social influences, the expansion and cognitive complexity of functions performed by the internet-enabled devices over time could influence internet use patterns. In this study, we investigate how the association between internet use and episodic memory difficulties over time varies between cohorts. We analyzed longitudinal data from the Health and Retirement Study (N = 15,703 in 2002; Aged 51 and older) between years 2002-2016 using mixed effects logistic regression models. Immediate and delayed word recall measures were used to assess episodic memory. Rate of internet use in the sample increased from 30% in 2002 to 53% in 2016. Rate of internet use among younger age groups was significantly higher in the baseline year. Younger age groups also showed a significantly higher rate of increase in internet use over time. In general, internet use decreased with episodic memory impairment. In addition to these effects, the effect of episodic memory on the rate of increase in internet use over time is lower in younger cohorts. These results indicate that younger cohorts of older adults are more likely to maintain internet use as they continue to age and therefore could better utilize technology for communication, social interactions and health interventions.

scholarly journals The Use of GIS Technology to Optimize COVID-19 Vaccine Distribution: A Case Study of the City of Warsaw, Poland

2021 ◽  
Vol 18 (11) ◽  
pp. 5636
Author(s):  
Sylwia Krzysztofowicz ◽  
Katarzyna Osińska-Skotak
Keyword(s):  
Herd Immunity ◽  
Research Work ◽  
Age Groups ◽  
Group Living ◽  
Population Group ◽  
Gis Technology ◽  
Vaccination Site ◽  
Global Challenge ◽  
Vaccine Distribution ◽  
The City

The COVID-19 pandemic is a global challenge, and the key to tackling it is vaccinating a specified percentage of the population to acquire herd immunity. The observed problems with the efficiency of the vaccination campaigns in numerous countries around the world, as well as the approach used at the initial stage of the National Immunization Program in Poland, prompted us to analyse the possibility of using GIS technology to optimize the distribution of vaccines to vaccination sites so as to minimize the period needed to vaccinate individual population groups. The research work was carried out on the example of Warsaw, the capital of Poland and the city with the largest population in the country. The analyses were carried out for the 60–70 and 50–60 age groups, in various approaches and for vaccines of different companies (Moderna, BioNTech, AstraZeneca), used to vaccinate people in Poland. The proposed approach to optimize vaccine distribution uses Thiessen’s tessellation to obtain information on the number of people in a given population group living in the area of each vaccination site, and then to estimate the time needed to vaccinate that group. Compared to the originally used vaccination scenario with limited availability of vaccines, the proposed approach allows practitioners to design fast and efficient distribution scenarios. With the developed methodology, we demonstrated ways to achieve uniform vaccination coverage throughout the city. We anticipate that the proposed approach can be easily automated and broadly applied to various urban settings.

Age-Related Differences in Throwing Techniques Used by the Catcher in Baseball

1994 ◽  
Vol 6 (3) ◽  
pp. 225-235 ◽  
Author(s):  
Shinji Sakurai ◽  
Bruce Elliott ◽  
J. Robert Grove
Keyword(s):  
High Speed ◽  
High Performance ◽  
Age Groups ◽  
Three Dimensional ◽  
Transformation Method ◽  
High Speed Photography ◽  
Two Phase ◽  
Ball Speed ◽  
Age Related ◽  
Release Speed

Three-dimensional (3-D) high speed photography was used to record the overarm throwing actions of five open-age, four 18-year-old, six 16-year- old, and six 14-year-old high-performance baseball catchers. The direct linear transformation method was used for 3-D space reconstruction from 2-D images of the catchers throwing from home plate to second base recorded using two phase-locked cameras operating at a nominal rate of 200 Hz. Selected physical capacity measures were also recorded and correlated with ball release speed. In general, anthropometric and strength measures significantly increased through the 14-year-old to open-age classifications, while a range of correlation coefficients from .50 to .84 was recorded between these physical capacities and ball speed at release. While many aspects of the kinematic data at release were similar, the key factors of release angle and release speed varied for the different age groups.

scholarly journals Variation principle in calculating the flow of a two-phase mixture in the pipes of the cooling systems in high-rise buildings

2018 ◽  
Vol 33 ◽  
pp. 02063 ◽  
Author(s):  
Andrey Aksenov ◽  
Anna Malysheva
Keyword(s):  
Channel Cross Section ◽  
Variation Principle ◽  
Two Phase ◽  
Liquid Phases ◽  
Rate Of Increase ◽  
Annular Layer ◽  
Gas Liquid Flow ◽  
The Stability ◽  
Air Conditioning Systems ◽  
Physical Laws

The analytical solution of one of the urgent problems of modern hydromechanics and heat engineering about the distribution of gas and liquid phases along the channel cross-section, the thickness of the annular layer and their connection with the mass content of the gas phase in the gas-liquid flow is given in the paper.The analytical method is based on the fundamental laws of theoretical mechanics and thermophysics on the minimum of energy dissipation and the minimum rate of increase in the system entropy, which determine the stability of stationary states and processes. Obtained dependencies disclose the physical laws of the motion of two-phase media and can be used in hydraulic calculations during the design and operation of refrigeration and air conditioning systems.

scholarly journals Prevalence of mumps antibodies in the Israeli population in relation to mumps vaccination policy and incidence of disease

2007 ◽  
Vol 136 (5) ◽  
pp. 688-693 ◽  
Author(s):  
Kh. MUHSEN ◽  
Y. ABOUDY ◽  
E. MENDELSON ◽  
M. S. GREEN ◽  
D. COHEN
Keyword(s):  
High School Students ◽  
Herd Immunity ◽  
Population Sample ◽  
Vaccination Policy ◽  
Birth Cohorts ◽  
Mmr Vaccine ◽  
School Students ◽  
Military Recruits ◽  
Israeli Population ◽  
Mumps Antibodies

SUMMARYWe examined the prevalence of mumps antibodies in the Israeli population in relation to mumps vaccination policy and past and subsequent incidence of disease. The levels of specific IgG antibodies against mumps were tested in 3330 residual sera collected during 1997–1998 from an age-stratified population sample. Against the background of a consistent MMR vaccination coverage of >90%, the age- and sex-adjusted seropositivity to mumps was 77·0%. No significant differences between genders were found. Seropositivity in the 10–13 years age group, born just before the introduction of the MMR vaccine, was the lowest (59%). These birth cohorts were the target of an outbreak of mumps in 2005 that occurred among high-school students and military recruits. A trend of waning immunity was observed between the first and second vaccine doses. The seroepidemiological data demonstrate that immunity levels below the herd immunity threshold, along with social mixing and crowded conditions facilitated the occurrence of mumps outbreaks. Periodical serosurveys are an essential component in the evaluation of the vaccination policy against mumps.

scholarly journals MORBIDITY WITH TEMPORARY LOSS OF WORK CAPACITY IN WORKING POPULATION: FEDERAL AND REGIONAL INDICES AND TRENDS OVER 2005 - 2014

2019 ◽  
Vol 96 (11) ◽  
pp. 1054-1059 ◽  
Author(s):  
Natalia A. Lebedeva-Nesevrya ◽  
V. G. Kostarev ◽  
N. V. Nikiforova ◽  
M. Yu. Tsinker
Keyword(s):  
Incidence Rate ◽  
Age Groups ◽  
Federal District ◽  
Work Capacity ◽  
Working Population ◽  
Managerial Decisions ◽  
Perm Krai ◽  
Federal Districts ◽  
High Incidence Rate ◽  
Regional Product

The article presents data on morbidity with temporary loss of work capacity (MTLWC) among working population in the whole of the Russian Federation and federal districts throughout the period from 2005 to 2014. According to official statistics, common number of losses of working days is shown to decline with a rate of about 1.1-1.3% per year mainly due to a reduction in the number of cases of diseases. The Urals and Privolzhsky Federal Districts are characterized by highest rates both of the incidence rate and the number of days of MTLWC. For the example, the Perm Krai (Privolzhsky Federal District) as a region with a typical MTLWC structure was shown to represent greatest losses of working days in the age groups of 25-29 and 50-54 years of workers of both genders. The consistent high incidence rate of injuries, poisoning and other effects of external influences in working men under the age of 24 years is of particular concern. The situation testifies the need to create targeted programs to prevent diseases in young workers, who in subsequent years will form the bulk of the country’s productive forces. At the regional level MTLWC is established to account for an annual loss of about 1.3-1.5% of the gross regional product. The adoption of effective managerial decisions to reduce MTLWC is shown to allow solve not only medical and demographic, but also economic problems in certain regions and the country as a whole.

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