Post-vaccination Immunity Research Articles

Patterns in the development of collective immunity to SARS-CoV-2 during the COVID-19 pandemic

The ongoing coronavirus disease (COVID-19) pandemic over the past three years has caused close attention to the problem of herd immunity, which is understood as: "resistance to the spread of a contagious disease within a population or herd". Collective immunity is formed both as a result of infection (natural spread of the pathogen in a population of susceptible individuals) and as a result of the use of specific vaccines. During the COVID-19 pandemic, both mechanisms for the formation of collective immunity were realized. In the first wave, there was a natural formation of collective immunity to the virus following recoveries from COVID-19 caused by pandemic spread of SARS-CoV-2. Starting from December 2020, the widespread use of specific vaccines against SARS-CoV-2 began in the USA, Great Britain, China, Russia, and a number of other countries. This launched the process of post-vaccination collective immunity formation; its features have depended on the vaccine types implemented. Currently, in those countries where vaccination and revaccination of recovered patients is widely carried out, immunity is "hybrid" in nature. Several commonalities should be noted in the pandemic experience: a somewhat regular, periodic (wavelike) nature of the COVID-19 epidemic process; changes in pathogen genetics in variants in all countries; and expansive mass vaccination programs in many populations. From these, we can draw some conclusions about the general trend for all countries in the formation of collective immunity during the pandemic: At the beginning of the pandemic in 2020, overall population seroprevalence did not exceed 20%. Other findings were: the highest seroprevalence rates were noted in the children's age group; pronounced regional differences were revealed; and the highest indicators were noted among medical workers. Collective immunity developed as a result of infection or illness, and in the majority of seropositive volunteers, it was represented by antibodies to both antigens. At the height of the pandemic in the summer of 2021, population seroprevalence reached 50%. This was due to both a significant number of convalescents and the start of mass vaccination campaigns. In all countries, specific differences in seroprevalence (by age, region, profession) leveled out, leading to more uniformity. During this period, the formation of "hybrid" immunity is clearly prominent, and the proportion of individuals with antibodies to RBD alone increased (due to vaccination with vector vaccines). Later, mass vaccination, as well as involvement of most of the population in the epidemic process due to the emergence of the highly contagious Omicron strain, raised the level of collective immunity to 80-90%. This led to a sharp decrease in COVID-19 incidence in the second half of 2022 in all countries participating in the study. In the later stages of the pandemic (2022-2023), almost 90% of seropositive volunteers had hybrid immunity, reflected as antibodies to both antigens (Nc, RBD).

The Impact of the COVID-19 Pandemic on the Health of People with Mental Disorders

The aim of the review was to analyze published studies on the impact of the COVID-19 pandemic on the health status (mental and physical) of people with mental disorders. Materials and methods: by keywords “COVID-19”, “depressive disorders”, “affective disorders”, “schizophrenia”, “anxiety disorders” search for papers in English and Russian in the databases MEDLINE/ PubMed, Scopus, Web of Science, eLibrary for the period from 2017 to 2022 was carried out. Conclusion : the analysis of published works has demonstrated that factors such as social distancing, isolation, or changing the availability of medical services can have a significant influence on the health of people with mental disorders. It has been established that people suffering from mental illness are at a higher risk of contracting COVID-19, they have less effective post-vaccination immunity and have a more severe course of the disease. The past coronavirus infection can lead to both an increase in pre-existing symptoms of a mental disorder, and the emergence of new ones. Possible physiological mechanisms of mental disorders after past COVID-19 include a wide range of pathogenetic processes: from prolonged systemic inflammation of varying intensity to vascular microthrombosis and neurodegenerative changes. Cognitive impairment during COVID-19, associated with damage to brain structures by the virus, may exacerbate existing psychopathological symptoms. The special features of psychopathological symptoms that develop in response to a pandemic situation are closely related to the structure of the previous mental status of patients, and therefore the types of psychosocial assistance needed is different for people with various mental disorders.

Clinical laboratory diagnostics of antibodies to SARS-CoV-2: from a QR code to the reality

Background: The immune response to SARS-CoV-2 includes the production of specific immunoglobulins to protein antigens of SARS-CoV-2. Depending on the type and level of immunoglobulins, it is possible to assess the stage of the disease and evaluate the effectiveness of vaccination. The main approach to the determination of immunoglobulins to SARS-CoV-2 in human biological fluids is enzyme-linked sorbent immunoassay. Its data, in particular, are used to issue an electronic COVID-19 certificate with a QR code. However, the qualitative and quantitative composition of immunoglobulins for a QR code is not officially regulated. Aim: measuring the immunoglobulins level in the human blood serum with different types of immunity to the new coronavirus infection (COVID-19) to select the most informative indicators of protective immunity. Methods: The study included 76 blood serum samples from male and female volunteers (age, 18 to 50 y.o.) in compliance with the ethical standards. The detection of IgA, IgM, IgG (total to different regions of SARS-CoV-2, S-protein IgG and RBD-fragment IgG), IgG avidity, and the level of the SARS-CoV-2 N-antigen was performed by enzyme-linked immunosorbent assay (ELISA) using commercially available reagent kits. Results: The indicators of the level of antibodies (both "protective" IgG and IgA of the initial phase of infection) are most pronounced in persons who have been vaccinated and have had COVID-19, and least pronounced in unvaccinated people. For recovered unvaccinated individuals, the level of total protective antibodies and IgG to the S-protein, including the RBD fragment, is the lowest; the avidity of IgG is lower than that in the other groups, too. The IgG avidity in vaccinated patients is higher than that in recovered ones. It should be noted that there were no differences in the level of both total IgG to SARS-CoV-2, to the S-protein and to the RBD-fragment of the S-protein for recovered and vaccinated individuals. Conclusion: The analysis of COVID-19 immunoglobulins indicates a different profile of the humoral immune response following vaccination and previous infection with COVID-19. To quickly assess the immune response to previous and current COVID-19 infection, as well as to detect the post-vaccination immunity, it is advisable to use the total level of IgG to SARS-CoV-2. For deeper assessment of protective immunity and production of protective antibodies, it is better to evaluate the quantitative content of IgG to the S protein and its RBD fragment. The equal level of IgA in the experimental groups indicates an ongoing interaction with SARS CoV-2 in the population. Thus, the electronic COVID-19 certificate is of little use when it is formed by only one of the indicators without taking into account the rest.

Assessment of humoral immunity to SARS-CoV-2 by a sample examination of medical workers in a large specialized multidisciplinary hospital

Introduction. The assessment of specific IgG antibodies to RBD Spike SARS-CoV-2 and their quantitation permit to calculate the intensity of immunity to COVID-19, i.e. to determine the level of immunity to infection, the risk of infection, the severity of the disease, as well as the ability to prevent death. Meanwhile, the protective level of antibodies is not determined. Therefore, determining the nature of immunity and quantitation of IgG antibodies to RBD Spike SARS-CoV-2 make it possible to assess the effectiveness of preventive measures and correct them in a timely manner.
 The aim is to determine the presence of IgG antibodies to RBD Spike SARS-CoV-2, their concentrations, and the nature of humoral immunity in different age and occupational groups of employees in a closed-type hospital after the completed vaccination with "Gam-Covid-Vac" vaccine.
 Materials and methods. The blood sera of 310 members of medical staff who received a full course of immunization with the "Gam-Covid-Vac" vaccine were tested using "SARS-CoV-2-ELISA-IgG" kit according to instructions provided in 21.20.23-004-28597318-2020, RU No. RZN 2021/15898. IgG antibodies to RBD Spike SARS-CoV-2 were quantitated against WHO standard NIBSC 20/136.
 Results. Specific IgG antibodies to RBD Spike SARS-CoV-2 were found in 92.9% of the examined individuals, including 67.4% having hybrid immunity (both vaccine- and infection- induced), and 25.5% having post-vaccination immunity after immunization with the "Gam-Covid-Vac" vaccine; 7.1% participants were nonimmune. A higher level of IgG antibodies to RBD Spike SARS-CoV-2 was detected in the group of individuals with hybrid immunity (p 0.01). Only 11.6% of employees had a protective antibody level of more than 300 BAU/ml.
 Discussion. Most employees with hybrid immunity were identified in the older age groups and in the junior medical staff. The results of this serological study, taking into account the age and professional aspects, can serve as the basis for adjusting preventive measures in medical institutions.

Pathological features of the lungs and liver of piglets under conditions of constant vaccination of livestock against circovirus infection

The pathogenicity of PCV 2 in the body of vaccinated piglets was studied based on the results of pathomorphological changes in the lungs and liver of animals. The work was carried out on commercial piglets vaccinated with the vaccine Ingelvak CircoFLEX (Germany) against circovirus. The work used clinical, zootechnical, enzyme immunoassay and pathomorphological research methods. It has been established that under the conditions of ongoing vaccination of piglets against PCV2, 30.3% of piglets still do not have virus-neutralizing antibodies. The main reason for the culling of animals are circovirus diseases that have respiratory clinical signs, as well as signs of multisystem wasting syndrome, determining the safety of the livestock at the level of 68.05%, the average live weight of 1 head at the moment of its transfer for fattening is 40.44±0.78 kg, and the average daily gain in live weight is 346.00±9.18 g. At autopsy, sick piglets reveal an increase in the lungs and liver, and the signs of inflammation in them, as a result of circulatory disorders, damage to the lymphoid tissue, the development of dystrophic and necrotic changes. The results of the research suggest that in order to increase the efficiency of the formation of post-vaccination immunity, specific medical preparations can be used to stimulate the immune response of the body, as well as to enhance the resistance of the lymphoid tissue of the lungs and liver in animals.

Maintaining immunological memory to the SARS-CoV-2 virus during COVID-19 pandemic

The question on the duration and effectiveness of post-infection vs post-vaccination SARS-CoV-2 immunity remains in the focus of numerous studies. The aim of the work was to examine the duration of maintained post-infection and post-vaccination SARS-CoV-2 immunity as well as formation of hybrid (vaccination after infection) and breakthrough (repeated disease or disease after vaccination) immunity in the context of an ongoing COVID-19 pandemic. 107 adults with mild or moderate COVID-19 318 months after the disease and 30 subjects vaccinated twice with the Sputnik V vaccine were examined 16 times. Antibodies against SARS-CoV-2 virus were determined by ELISA on the SARS-CoV-2-IgG quantitative-ELISA-BEST test systems. The antibody avidity was measured by additional incubation with and without denaturing solution. Mononuclear cells were isolated from blood by gradient centrifugation, incubated with and without coronavirus S-protein for 20 hours, stained with fluorescently labeled antibodies, and the percentage of CD8highCD107a+ was counted using FACSCanto II cytometer. It was shown that in the group of convalescent and vaccinated subjects, the level of virus-specific antibodies decreased more deeply in individuals with initially high humoral response, but 9 months later the decrease slowed down and reached a plateau. The antibody avidity rose up to 50% and persisted for 18 months. Cellular immunity in recovered patients did not change for 1.5 years, while in vaccinated patients it gradually decreased 6 months later, but remained at detectable level. After revaccination, a significant increase in the level of antibodies, avidity up to 67.6% and cellular immunity returned to the initial level were noted. Hybrid immunity turned out to be significantly higher than post-infection and post-vaccination immunity. The level of antibodies increased to 1218.2 BAU/ml, avidity to 69.85%, and cellular immunity to 9.94%. Breakthrough immunity was significantly higher than that after the first disease. The level of antibodies rose to 1601 BAU/ml, avidity up to 81.6%, cellular immunity up to 13.71%. Using dynamic observation of four COVID-19 convalescents, it has been shown that in the context of the ongoing pandemic and active coronavirus mutation, natural boosting occurs both asymptomatically and as a result of a mild re-infection, which prevents disappearance of SARS-CoV-2 humoral and cellular immunity.

Changes in tension of immunity to pertussis by time of immunization

Objective: to identify the features of post-vaccination immunity to whooping cough, the state of immuno-logical reactivity in children of the Stavropol Territory. Material and methods. A comprehensive clinical and laboratory examination of 242 children aged 1 to 17 years was carried out. Serological examination of children was carried out at different times after revaccination, as well as an analysis of the parameters of the immune system in children of this age group. Results. A study of the level of immunity tension in children of early and school age showed that a low level of anti-pertussis antibodies was detected in 55% of children already 2-3 years after immunization, meaning that these children were at risk of pertussis, while protective titers of anti-pertussis antibodies were detected only in 34%, and high titers 11% of children. Conclusion. Children vaccinated in anamnesis in Stavropol Territory lose specific antibodies 3 years after the initial vaccination complex.

Does Intrauterine Exposure of the Foetus to Immunosuppressive Drugs Used by the Mother-The Organ Recipient-Affect the Development of Post-Vaccination Immunity against Selected Viral Diseases in Children of These Mothers in Postnatal Life?

Pregnancy in women who are organ recipients has long been a controversial issue due to the lack of data on the safety of immunosuppressive drugs for the developing foetus. Scientific data show that the effect of immunosuppressants on the foetus causes an impairment of T and B lymphocyte function and a reduction in their total number. For this reason, some authors recommend delaying the obligatory immunization of infants. The aim of the study is to analyse the impact of chronic immunosuppressive therapy used during pregnancy by women after organ transplantation on the effectiveness of anti-viral vaccinations in the children of these women. Concentrations of post-vaccination IgG antibodies (measles, HBV, polio) in 18 children of post-transplant mothers (9KTRs; 9LTRs) were determined using the ELISA method. The results were compared with the control group (n = 21). The incidence of vaccination AEs was also analysed. There were no significant differences between the analysed groups in the concentrations of antibodies against HBV, measles and polio (p > 0.05). No difference was observed in the immunogenicity of HBV, polio and measles vaccinations between children of post-transplant mothers and the general population. The immunization of children of post-transplant mothers is safe, and the percentage of adverse post-vaccination events does not differ from the general population. The obtained study results do not indicate the necessity for modifying the vaccination program for HBV, measles, and polio in this group of patients.

ATR-FTIR spectrum analysis of plasma samples for rapid identification of recovered COVID-19 individuals.

The development of fast, cheap and reliable methods to determine seroconversion against infectious agents is of great practical importance. In the context of the COVID-19 pandemic, an important issue is to study the rate of formation of the immune layer in the population of different regions, as well as the study of the formation of post-vaccination immunity in individuals after vaccination. Currently, the main method for this kind of research is enzyme immunoassay (ELISA, enzyme-linked immunosorbent assay). This technique is sufficiently sensitive and specific, but it requires significant time and material costs. We investigated the applicability of attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopy associated with machine learning in blood plasma to detecting seroconversion against SARS-CoV-2. The study included samples of 60 patients. Clear spectral differences in plasma samples from recovered COVID-19 patients and conditionally healthy donors were identified using multivariate and statistical analysis. The results showed that ATR-FTIR spectroscopy, combined with principal components analysis (PCA) and linear discriminant analysis (LDA) or artificial neural network (ANN), made it possible to efficiently identify specimens from recovered COVID-19 patients. We built a classification models based on principal component analysis (PCA) associated with linear discriminant analysis (LDA) and artificial neural network (ANN). Our analysis led to 87% accuracy for PCA-LDA model and 91% accuracy for ANN, respectively. Based on this proof-of-concept study, we believe this method could offer a simple, label-free, cost-effective tool for detecting seroconversion against SARS-CoV-2. This approach could be used as an alternative to ELISA. This article is protected by copyright. All rights reserved.

Seroprevalence of hepatitis B infection and active immunization in Ecuadorian Amazonian indigenous people: A cross-sectional study

Introduction: Hepatitis B surveillance is crucial. We proposed to describe the seroprevalence of Hepatitis B infection and the associated factors among Ecuadorian Amazonia communities. Outline: A serologic cross-sectional study was carried out in subjects over two years old. We classified seropositivity according to the Centers of Diseases Control criteria and recorded sex, age, temporary migration, sometime Hepatitis B in their life, and previous vaccination. Results: Out of 215 participants, 50.0%, 8.8%, 1.9%, and 1.4% were susceptible, immune due to natural infection, chronic infection, and early acute HBV infection, respectively. Of the 8 people who reported having ever been diagnosed with Hepatitis B, none showed chronic or acute infection and one was positive for immunity due to the vaccine. HBsAg was found in 3.3% (95% IC 0.9-7.0) and was higher among those who migrate 7.7% (p-value 0.04). 16.3% (95% CI 11.6-21.4) was immune due to HBV vaccination. Among the 58 participants who declared having received the vaccine, 20.7% presented post-vaccine immunity. Implications: Participants who should have benefited from the vaccination campaign (susceptible) are those with the lowest immune response due to vaccination. To assessing the burden of viral hepatitis in people living in marginalized areas and guide preventive measures is mandatory.

Assessment of humoral immunity to SARS-CoV-2 among employees of medical organizations in the Republic of Tatarstan

BACKGROUND: Since the beginning of the new coronavirus infection pandemic, preventive measures aimed at combating the spread of the pathogen and preventing the development of severe forms of infection and deaths have improved. Despite the absence of a legally established, generally accepted post-vaccination protective value of antibodies to coronavirus, the study of the presence of antibodies and the determination of their amount in the blood serum of the vaccinated population continues.
 AIM: This study presents the results of post-vaccination humoral immunity to SARS-CoV-2 in medical organizations regardless of their infectious disease history.
 MATERIALS AND METHODS: This study involved employees of medical organizations of the State Autonomous Health Institution Republican Clinical Dermatovenerologic Dispensary of the Ministry of Health of the Republic of Tatarstan named after Professor A.G. Ge in Kazan and the State Autonomous Health Institution City Polyclinic No. 3 in Naberezhnye Chelny. Three hundred ninety-three people (including 350 women) were vaccinated with the two-component vaccine GamCovidVac (Sputnik V). After a sufficient amount of time passed for the formation of an immune response, more than 21 days. The blood sera of these 393 people were examined for the determination of specific IgG to SARS-CoV-2 by enzyme immunoassay using the Vector-Best kit (Novosibirsk, Russia). Statistical analysis was performed using StatTech v.3.0.9 (developer, Stattech LLC, Russia).
 RESULTS: The median age of the subjects was 47 (Q1Q3: 3959) years. The mean antibody titer level was 570 (Q1Q3: 1281150 BAU/ml). A correlation analysis of the relationship between titer levels and age at the time of vaccination was performed. According to the results, a weak direct relationship was established. There was no connection when assessing the antibody titer level dependence on vaccination duration after the second component at the time of checking the titers.
 CONCLUSIONS: The ongoing pandemic of a new coronavirus infection with the emergence of new forms of the disease caused by other virus strains, the improvement in prevention methods, requires constant monitoring of the epidemiological situation with the study of the vaccine effectiveness, including the cellular level.

Post-Vaccination and Post-Infection Immunity to the Hepatitis B Virus and Circulation of Immune-Escape Variants in the Russian Federation 20 Years after the Start of Mass Vaccination.

A neonatal vaccination against the Hepatitis B virus (HBV) infection was initiated in Russia 20 years ago, with catch-up immunization for adolescents and adults under the age of 60 years launched in 2006. Here, we have assessed the humoral immunity to HBV in different regions of Russia, as well as the infection frequency following 20 years of a nationwide vaccination campaign. We have also evaluated the role of immune-escape variants in continuing HBV circulation. A total of 36,149 healthy volunteers from nine regions spanning the Russian Federation from west to east were tested for HBV surface antigen (HBsAg), antibodies to HBV capsid protein (anti-HBc), and antibodies to HBsAg (anti-HBs). HBV sequences from 481 chronic Hepatitis B patients collected from 2018-2022 were analyzed for HBsAg immune-escape variants, compared with 205 sequences obtained prior to 2010. Overall, the HBsAg detection rate was 0.8%, with this level significantly exceeded only in one study region, the Republic of Dagestan (2.4%, p < 0.0001). Among the generation vaccinated at birth, the average HBsAg detection rate was below 0.3%, ranging from 0% to 0.7% depending on the region. The anti-HBc detection rate in subjects under 20 years was 7.4%, indicating ongoing HBV circulation. The overall proportion of participants under 20 years with vaccine-induced HBV immunity (anti-HBs positive, anti-HBc negative) was 41.7% but below 10% in the Tuva Republic and below 25% in the Sverdlovsk and Kaliningrad regions. The overall prevalence of immune-escape HBsAg variants was 25.2% in sequences obtained from 2018-2022, similar to the prevalence of 25.8% in sequences collected prior to 2010 (p > 0.05). The population dynamics of immune-escape variants predicted by Bayesian analysis have remained stable over the last 20 years, indicating the absence of vaccine-driven positive selection. In contrast, the wild-type HBV population size experienced a rapid decrease starting in the mid-1990s, following the introduction of mass immunization, but it subsequently began to recover, reaching pre-vaccination levels by 2020. Taken together, these data indicate that it is gaps in vaccination, and not virus evolution, that may be responsible for the continued virus circulation despite 20 years of mass vaccination.

Utility of Roche Elecsys anti-SARS-CoV-2 S in ascertaining post-vaccine neutralizing antibodies

With widespread global COVID-19 vaccine coverage, a scalable, cost-effective, and standardized tool to ascertain post-vaccine immunity is a dire need. Neither clinical evaluations of vaccine efficacy, nor live virus antibody neutralization assays fulfill these criteria. Commercially available anti-S binding immunological assays have the potential to fill this gap, but need to be systematically evaluated for their utility to serve as surrogates for the aforementioned, widely accepted tools of determining vaccine efficacy. In this study, we evaluated an anti-S binding immunological assay (Roche Elecsys Anti-SARS-CoV-2 S) by utilizing two hundred and fifty-five archived serum specimens, either pre-pandemic, or those exposed to natural infections or vaccines with their neutralizing titers pre-determined through a live virus, pseudotyped antibody neutralization assay. Roche Elecsys Anti-SARS-CoV-2 S demonstrated good sensitivity (98%) and specificity (99%), just as has been reported in some other previously conducted studies using this assay. Only a mild correlation, however, with the live virus pseudotyped lentivirus antibody neutralization assay (Spearman's r = 0.26) was observed. We conclude that, as such, Elecsys Anti-SARS-CoV-2 S has a high sensitivity and specificity for detecting anti-SARS-CoV-2 S proteins, though the assay does not always correlate well with live virus assays for quantitative outcomes.

An Evaluation of Serological Tests to Determine Postvaccinal Immunity to SARS-CoV-2 by mRNA Vaccines.

The duration of the protective efficacy of vaccines against SARS-CoV-2 is unknown. Thus, an evaluation of the clinical performance of available tests is required. To evaluate the clinical performance of LFIA immunoassay compared to ELIA and CLIA immunoassays available in Europe for the detection of IgG antibodies generated by mRNA vaccines against SARS-CoV-2. Two automated immunoassays (the EUROIMMUN anti-SARS-CoV-2 IgG S1 ELISA and the LIAISON de Diasorin anti-SARS-CoV-2 IgG S1/S2 test) and a lateral flow immunoassay (the Livzon LFIA anti-SARS-CoV-2 IgG S test) were tested. We analyzed 300 samples distributed in three groups: 100 subjects aged over 18 years and under 45 years, 100 subjects aged between 45 and 65 years, and 100 subjects aged over 65 years. The samples were collected before vaccination; at 21 days; and then at 1, 2, 3, and 6 months after vaccination. The sensitivity, specificity, positive predictive value, negative predictive value, positive probability quotient, negative probability quotient, and concordance (kappa index) were calculated for each serological test. The maximum sensitivity values for IgG were 98.7%, 98.1%, and 97.8% for the EUROIMMUN ELISA, Abbott CLIA, and Livzon LFIA tests, respectively, and the maximum specificity values for IgG were 99.4%, 99.9%%, and 98.4% for the ELISA, CLIA, and LFIA tests, respectively, at the third month after vaccination, representing a decrease in the antibody levels after the sixth month. The best agreement was observed between the ELISA and CLIA tests at 100% (k = 1.00). The agreement between the ELIA, CLIA, and LFIA tests was 99% (k = 0.964) at the second and third month after vaccination. Seroconversion was faster and more durable in the younger age groups. Our study examined the equivalent and homogeneous clinical performance for IgG of three immunoassays after vaccination and found LFIA to be the most cost-effective, reliable, and accurate for routine use in population seroconversion and seroprevalence studies.

Aspects of the formation of post-vaccination immunity against porcine circovirus infection and its correction

Relevance. Prevention of circovirus diseases in swine management is one of the urgent problems in the industry. The article provides data on the results of the use of two regimens for administering vaccines against circovirus infection to piglets according to immunological, biochemical and zootechnical indicators.Methods. The work was carried out on piglets, which were vaccinated with "Ingelvak CircoFLEX" vaccine (Germany) against circovirus at the age of 21 days, in the experimental group it was administered together with "leukocytic lysate" obtained from donors hyperimmunized with this vaccine. Evaluation of the effectiveness of post-vaccination immunity formation was carried out based on the results of immunological, biochemical, zootechnical and statistical studies.Results. It was established that when the vaccination was combined with the introduction of «leukocytic lysate» from hyperimmunized donors, the number of piglets with a positive test for the presence of viral neutralizing antibodies was 79.30–82.33%, in the control — 67.80–71.60%, as a result of changes in the leukocytic blood pool within the normal limits. In piglets of experimental group blood concentration of total protein and albumins starting from 60-day age exceeds control level by 7.73–8.68 and 17.84–30.27% respectively. In the experimental group, compared with the control group, the co-storage of animals is increased by 9.02%, the live weight of piglets at the end of the nursery period is increased by 12.88 kg, or 31.85%, based on one head and the value of medium increases in live weight — by 90 g, or 26.01%.

Postvaccination Immunogenicity of BNT162b2 SARS-CoV-2 Vaccine and Its Predictors in Pediatric Inflammatory Bowel Disease.

We prospectively compared the postvaccination immunity to messenger ribonucleic acid BNT162b2 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine of our pediatric patients over 12 years old with inflammatory bowel disease (IBD) to that of healthy controls and looked for predictors of its robustness. Anti-receptor binding domain, anti-spike S2, and anti-nucleocapsid immunoglobin-G (IgG) and immunoglobin-A levels were measured in 139 pediatric patients with IBD [65 fully vaccinated (2 doses), median age 16.3, interquartile range (IQR) 15.2-17.8 years, median time from vaccination (IQR) 61.0 (42.0-80.0) days] and 1744 controls (46, 37-57 years) using microblot array. All IBD and control patients developed positive anti-receptor binding domain IgG antibodies at comparable titers. The proportion of observations with positive anti-spike S2 IgG was higher in patients with IBD than in controls [63% vs 21%, odds ratio 2.99 (1.51-5.90)], as was its titer [median (IQR) 485 (92-922) vs 79 [33-180] IU/mL]. Anti-receptor binding domain and anti-spike S2 IgG levels were associated with IBD status. We found an association between anti-spike S2 IgG levels and time since vaccination (β -4.85, 95% CI -7.14 to 2.71, P = 0.0001), history of SARS-CoV-2 polymerase chain reaction positivity (206.76, 95% CI 39.93-374.05, P = 0.0213), and anti-tumor necrosis factor treatment (-239.68, 95% CI -396.44-83.55, P = 0.0047). Forty-three percent of patients reported vaccination side effects (mostly mild). Forty-six percent of observations with positive anti-nucleocapsid IgG had a history of SARS-CoV-2 infection. Patients with IBD produced higher levels of postvaccination anti-spike S2 antibodies than controls. Previous SARS-CoV-2 infection is associated with higher production of postvaccination antibodies and anti-tumor necrosis factor treatment with lower production.

Formation of anti-infectious and post-vaccination anti-SARS-CoV-2 humoral immunity in medical workers of the perinatal center

In the context of the global spread of the new coronavirus infection, studies aimed at investigating formation of anti-infectious and post-vaccination immunity are of special importance, which is necessary to prevent and reduce morbidity and mortality due to SARS-CoV-2 infection. Purpose: to assess anti-infectious immunity against SARS-CoV-2 in various forms of the disease and development of post-vaccination humoral reactions in medical workers of the perinatal center.&#x0D; Materials and methods. A study of blood serum was carried out to assess SARS-CoV-2-specific IgM and IgG antibodies in 119 medical workers recovered after COVID-19, divided into groups based on the disease severity (mild, moderate and asymptomatic), as well as in 62 vaccinated employees, divided into groups according to age. Semi-quantitative measurement of virus-specific antibodies was carried out by ELISA with test systems SARS-CoV-2-IgG-ELISA-BEST and SARS-CoV-2-IgM-ELISA-BEST. Statistical processing of the research results was carried out using Microsoft Excel 2010 and Statistica 6. Quantitative characteristics were presented as median (ME), lower and upper quartiles (LQ1-UQ3); qualitative parameters as absolute value and relative number (%). Difference between groups was analyzed by using the 2 test (qualitative) and the MannWhitney U-test (quantitative).&#x0D; Results. The results of the study showed that the majority of employees with a moderate-severe form of SARS-CoV-2 had a high level of IgG (PR a positivity rate of more than 9.0 arbitrary units) 9 months after the disease compared to those who suffered from mild or asymptomatic (83.3% versus 25.8% and 13.3%, p 0.017) infection. The duration of IgG circulation after former illness had no relation to its severity and patient age. The effectiveness of the primary vaccination Sputnik V and revaccination with Sputnik Light and KoviVak was 100% after inoculating the vaccine second component. The lowest level of antibodies after the first vaccination is recorded in persons over 60 years old (1.48 (1.123.25 versus PR = 8.48(5.7810.11) and 9.27 (5.8410.31) arbitrary units, p 0.017)), in comparison with young and middle-age subjects. The speed SARS-CoV-2 elimination of IgG at 6, 9 or more months after vaccination depends on relevant initial peak antibody concentration. Subjects who were initially vaccinated with the KoviVac vaccine, IgG was not detected 2 months after vaccination. The protective effect of Sputnik V, Sputnik Light, KoviVac after re-infection with SARS-CoV-2 averages 71.2%.&#x0D; Conclusion. Thus, the results obtained on assessing anti-infectious and post-vaccination immunity against SARS-CoV-2 emphasize the need for further studies on a larger patient cohort, especially in those with asymptomatic infection as well as the elderly subjects.

Laboratory assessment of state of post-vaccination humoral immunity to infections with aerosol transmission mechanism

The review considers questions about the place of laboratory diagnostics in preventive medicine, in particular, about the possibilities of using laboratory methods in controlling the vaccination of infections with an aerosol transmission mechanism (measles, rubella, mumps, chickenpox, influenza, pneumococcal infection, pertussis, diphtheria, COVID-19). The article highlights the main laboratory methods of seromonitoring (enzyme immunoassay, radial hemolysis reaction in gel, dot-immunoassay, antibody avidity determination, hemagglutination inhibition reaction, microneutralization reaction, FAMA, plaque suppression reaction), their advantages and disadvantages. Also presented a block of data on alternative biomarkers (enzymes, lipids, trace elements, hormones, etc.). which serve as potential predictors of vaccination efficacy. The search for new biomarkers of the effectiveness of the formation of post-vaccination immunity opens up new possibilities for predicting the effectiveness of vaccination, which makes their study a promising direction in the field of vaccinology and laboratory immunology.

Contribution of some immunological and metabolic factors to formation of piglets’ post-vaccination immunity

The role and responsibility of natural resistance factors, protein and lipid metabolism in the formation of piglets post-vaccination immunity against circovirus is researched. Blood was taken for tests before and on the 15th, 40th and 70th day after the vaccination. The sampled blood was analyzed to determine immunological and biochemical parameters. It was revealed that before vaccination, 31.46% of the studied samples have a positive reaction in ELISA; their number increases to 67.80–71.16% on the 40th and 70th days after vaccination.In the blood of piglets, especially on the 40th and 70th day after the vaccination, the total count of leukocytes, monocytes and lymphocytes increases by 1.21; 2.28 times and 1.48 times, but neutrophils reduced by 1.74 times along with the phagocytic properties activation. The anabolic directivity of protein metabolism is defined by the synthesis of globulin proteins. At the same time albumin-synthesizing activity in a liver decreased and “cytolysis reaction” of hepatocytes was detected. In the lipid profile of piglets’ blood, the content of LDL‑cholesterol increased by 1.44 times, while that of triglycerides decreased by 2.64 times. X‑ray spectral analysis revealed the correlation between the formation of post-vaccination immunity and two factors: the factor of the principal component (PC) 1, which is predominantly associated with indicators of natural resistance, and PC2, which is associated with metabolism indicators. The research results show that in order to increase the efficiency of formation of post-vaccination immunity in piglets, it is necessary to combine vaccination with hepatoprotective drugs.

Longitudinal monitoring of post-vaccination immunity against hepatitis B in children after standard immunization in the first year of life and optimization of vaccination strategy

A clinical and laboratory examination of 62 children aged 10—17 years vaccinated against hepatitis B according to the standard scheme (0—1—6 months) in the first year of life strictly according to the National Calendar of preventive vaccinations in a standard dose (10 micrograms of recombinant HBsAg) with a monocomponent vaccine was carried out.The majority of children (58%) had indicators of seroconversion of HBsAg — anti-HBs-antibodies. This indicates the fact of long-lasting Grund immunity — 10—17 years after timely 3-fold immunization against hepatitis B according to the standard scheme at a standard dose (10 mcg of recombinant HBsAg in the first year of life in the absence of Wooster immunization (revaccination) in subsequent age periods, including children with a burdened premorbid background (87.1% among those observed). Since among those observed were children with invasive medical interventions (50%), the established fact reflects the protective effect of standard Grund immunization even in children at risk — with a positive parenteral history. At the same time, the total assessment of serological and molecular biological results found that after triple immunization against hepatitis B according to the standard scheme in the first year of life, out of 62 children aged 10—17 years, the proportion of seronegative was 42%. Low levels of antibodies (10—100 IU/l) were detected in 43% of cases, high (100—1000 IU/l) — in 15% of cases. No child had an antibody level exceeding &gt;1000 IU/l. These results require the development of new approaches to immunization of children against hepatitis B with mandatory revaccination at an older age.