Relevance.The strategy for the development of vaccine prevention in the Russian Federation among other areas involves improving the National schedule of preventive vaccinations and ensuring its flexibility, taking into account the current epidemic situation and the emergence of new vaccines.

Goal: to Assess the socio-economic damage from five vaccine-controlled infections in different vaccine prevention scenarios.

Materials and methods: a simulated retrospective model was constructed with a time horizon of 3 years (2016-2018), which assumes an assessment of changes in lost/ saved years of life including in monetary terms in the context of differentiated disease outcomes and vaccine costs under different scenarios of vaccination coverage and the vaccine prevention algorithm.

Results: if the established algorithm is maintained and the age cohort of children under 2 years of age is covered by vaccination, the annual loss of years of life will remain at a high level. Extending the five-component vaccine coverage to 60% of children in the 3-to 18-month age group will reduce losses to 20,215 years, saving 10,263 years of life (33.7% more than the current algorithm), and even more if coverage is close to 100%: annual losses will decrease to 2,134 years, which can provide 28,344 saved years of life (93% more than the current algorithm). The study showed that the more widely the combined pentavalent vaccine is used, the lower the average cost of saving each additional year of life.

Conclusions. Expanding the coverage of a combination vaccine provides the greatest additional benefits due to a faster increase in the number of saved years of life (benefits) compared to the increase in costs (cost of vaccines).

Relevance. The absence of a system of epidemiological surveillance of chronic lung infection (CLI) in patients with cystic fibrosis (CF) led to the spread of Staphylococcus aureus, Pseudomonas aeruginosa, Burkholderia cepacia complex and Achromobacter spp. among patients with CF during hospitalizations, that is proved by numerous cases of infection in patients with CF treated in various Russian clinics.

Aims. Determine the directions of epidemiological surveillance (ES) for CLI in patients with CF and preventive measures necessary to counteract the cross-infections among patients with CF and the spread of the dominant pathogens of CLI in the hospital.

Materials and methods. A complex of epidemiological, microbiological and molecular genetic methods was used.

Results and discussion. Based on the results of studies of the epidemiological and microbiological features of infections caused by the above-mentioned pathogens, the directions of ES and preventive measures for CF were determined. The tasks of the information-analytical unit, including the monitoring of morbidity and microbiological monitoring, are substantiated. It has been established that in the framework of microbiological monitoring, it is necessary to conduct bacteriological examination of biomaterial from the respiratory tract of patients with CF not less than 1 time per quarter, as well as at each outpatient visit and at hospitalization. The necessity of studying the phenotypic properties of pathogens contributing to long-term persistence in the patient's body of the CF, the definition and monitoring of the antibiotic sensitivity of microorganisms isolated from the patient over time, and the study of hypermutability was shown. One of the main tasks of monitoring is molecular genetic analysis of pathogens by PCR for the purpose of intraspecies identification, typing of pathogens and detection of epidemic markers and clones (including international ones), identification of genetic determinants of antibiotic resistance.

Conclusion. The introduction of ES for chronic lung infection will improve the quality of etiological diagnosis, will contribute early identification of the sources of infections and prevent the spread of CLI pathogens among patients with CF in hospitals and in non-hospital conditions, as well as optimize the tactics of CLI antimicrobial therapy. The main directions of preventing the spread of CLI pathogens should be the separation of patients with various infections during outpatient examination and isolation during hospitalization.

Relevance. Of the different subtypes, H3N2 influenza virus subtype has the highest variability and pathogenicity, often dominates in epidemiological seasons and induces high mortality exceeding its rate in pandemic. Aim is to identify some features of H3N2 molecular characteristics which could determine its high variability and domination over other subtypes in epidemiological seasons and discuss possible nature of the future influenza pandemic.

Materials and method. For the computer analysis, the database of the hemagglutinin (HA) and nucleoprotein primary structures of the H3N2, H1N1, В\Yamagata and В\Victoria strains isolated in the influenza epidemiological seasons 2009-2019 were used from the Internet. From the primary structure of their genes it were defined their translational codes. To trace the H3N2 subtype evolution in the last decade we compared the H3 dominant sequences of adjacent seasons to establish their changes.

Results. It has been indicated that H3, in comparison with H1 and В\Yamagata and В\Victoria hemagglutinins, contains more cysteine and the H3N2 strain very similar to the Hong Kong influenza virus continues to circulate in birds.The H3 gene translation code contains the least number of prohibitions. During last decade the H3 dominant sequence evolves faster than H1 one. The nucleoprotein of H3N2 strains is characterized by more content of lysine and less content of arginine.

Conclusion: H3N2, H1N1, В\Yamagata and В\Victoria strains one may conclude that least of all the nature restricts H3N2 to evolve and adapt to new hosts. It is likely that the following influenza pandemic will be generated by H1N1 subtype but H3N2 one and also be more mild than the 2019 pandemic.

Relevance. Vaccines based on capsular polysaccharides of pneumococci are not active against serotypes that are not included in the vaccine, non-capsulated strains and do not protect against carriage caused by other serotypes. Their use leads to the replacement of dominant serotypes of pneumococci, the appearance of highly virulent strains, changes in the microbial landscape of mucous membranes due to the appearance of other etiologically significant pathogens of respiratory tract diseases. This requires the creation of intraspecific anti-pneumococcal immunity, which will be facilitated by the development of serotype-dependent drugs, which will include protein-containing antigens of pneumococci.

Objective. Study of serotype-independent activity of protein-containing antigenic components obtained from freshly isolated and archival strains of S. pneumoniae.

Materials and methods. Strains of three serotypes of S. pneumoniae were used: archival strains of serotypes 6B N296, 19F N 298 and 10A N297 and freshly isolated serotypes 6B N 1121, 19F N 1055 and serogroup 10 N 1193 (from the cerebrospinal fluid of patients with purulent meningitis).. In the experimental protein-containing preparations EPCP obtained, the protein content was determined. Protective activity of EPCP and virulence of strains were determined in the model of intraperitoneal immunization and infection of BALB/c mice; LD50 was calculated using the generally accepted modified Kerber formula. The immunophenotype of lymphocytes previously isolated from donor-mice whole blood was studied by flow cytometry. Statistical analysis of the materials was carried out using parametric and nonparametric methods using the application package «Statistica for Windows», ver. 7.0 (Stat Soft, Inc); in statistical analysis, the significance level of p was assumed to be < 0.05.

Results and discussion. During cultivation there was the analysis of growth dynamics showed intensive accumulation of biomass of the archival strain N296 with low virulence, and lower - by virulent strain N 1121 isolated from the patient's cerebrospinal fluid. The protein content of drugs from serotype 6B strains did not differ. The strains of other serotypes isolated during the generalized infectious process were also more virulent than the archival strain. The effect on the immunophenotype of human lymphocytes of fractions of 50-100 kDa isolated from the initial preparations obtained by culturing serotype 6B, significantly increased only under the influence of the preparation from the archival strain. In the study of protective activity of the initial preparations from strains of serotype 6B and fractions with MM 50-100 kDa only triple immunization with the initial preparation from strain N 296, at a dose of 20 micrograms of protein per mouse, led to significantly greater survival of immunized mice from infection with the newly isolated virulent strain N 1121 of homologous serotype. A fraction of 30-100 kDa provided protection of mice twice immunized with 50 mkg of protein per mouse, with a high efficacy index of 8.9, even after infection with a freshly isolated strain of heterologous S. pneumoniae serotype 3 N 10196.

Conclusion. The protein-containing fraction with MM 30-100 kDa obtained from a low virulent archival strain of S. pneumoniae serotype 6B N296 possessed protective activity against a newly isolated virulent strain of heterologous serotype after double immunization. Under the action of the studied protein-containing fractions, activation of the cellular component of immune system with the involvement of innate immunity effectors and T-lymphocytes is shown. These data can be considered as a evidence for further study of EPCP to assess the possibility of their use in the design of anti-pneumococcal drug with serotype-independent protective activity.

Relevance. Despite the progress made in eliminating measles and rubella in the European Region, the measles situation has now worsened - four countries in the region have lost their status of eliminating measles.

Aims - to assess population immunity to measles in the Republic of Belarus, to determine its age and regional characteristics for identification of groups of higher risk of infection.

Results. The results of evaluation of IgG antibodies to measles under the conditions of a long-term (since 1967 - singledose immunization schedule, since 1987 - two-dose) vaccination, carried out in 2019, in 2229 residents of the Republic of Belarus 2-75 years of age are presented. Antibodies were detected using Serion ELISA classic Measles Virus IgG, Virion\Serion, Germany. Antibodies concentration 150 mIU/ml or more was considered as evidence of protection against measles. It was found that the level of seroprevalence against measles in the Republic of Belarus is 84.6%, that is slightly lower than the threshold level (90-95%) sufficient to prevent wide transmission of the virus in case of its importation. Level of seroprevalence was the highest in children 2-5 years old (96.9%) and in adults 46 years of age and older (93.0% or more) and did not reach 90% in all other age groups. The most susceptible to measles were adults 31-40 years old (born 1979-1988) - antibodies in protective concentrations were detected in less than 80% of them (31-35 years old - 78.9% and 36-40 years old - 78,4%). The mean antibody concentration in seropositive individuals also varied in age groups. A high concentration of antibodies (more than 1000 mIU/ml) was observed in children 2-5 years old, as well as in adults over 40 years old. Among the latter, the concentration of antibodies increased with age: 41-45 years old - 1069 mIU/ ml, 46-55 years old -1212 mIU/ml, 56-65years old -1582 mIU/ml, 66-75 -1849 mIU/ml. Among people 6-35 years old it was 500600 mIU/ml and was slightly higher among persons 36-40 years old (781 mIU/ml).

Conclusions. For further control of infection, along with maintaining a high (97% or more) level of routine immunization, it is necessary to ensure mopping up immunization of unvaccinated individuals and those without immunization data.

Relevance. Premature birth (PR) in the etiopathogenetic relationship is a clinical syndrome characterized by polyetiology, a chronic course of the process, the participation of the fetus in pathogenesis, a variety of clinical symptoms, and the involvement of genetic and environmental factors. The infectious factor is considered as the leading risk for the development of PR. According to the literature, more than 40% of PR is due to the presence of an infectious process. The most significant are intrauterine and cervical vaginal infections. Purpose of the study was a clinical and microbiological assessment of the state of the vaginal biotope in women with various options for spontaneous preterm birth.

Materials and methods. The diagnostic complex included bacterioscopic, bacteriological, and also molecular genetic studies. The object of the study was pregnant women with timely physiological delivery and with various types of preterm birth, who were hospitalized in specialized medical organizations of the Nizhny Novgorod region. A total of 260 patients were examined, and 1000 studies were conducted. Material for research was the contents of the vagina and cervical canal.

Results. The state of the vaginal biocenosis was characterized by pronounced irregularity in patients with different variants of spontaneous preterm birth. In women with premature rupture of the membranes, a local inflammatory process with the prevalence of conditionally pathogenic microflora over lactic acid bacteria was significantly frequent. Lactoflora prevailed among patients with true PR and with timely physiological labor in the composition of the vaginal biotope. In women with preterm labor with isthmic-cervical insufficiency, there were mixed disorders of the vaginal biocenosis.

Conclusions. The risk of developing spontaneous preterm birth is reliably determined by the state of the vaginal biocenosis.

Introduction. Available data indicate that the effectiveness of the strategy of "90-90-90" varies considerably between countries. For example, Australia with figures 90-90-79 (2016) has not achieved the negative trend of the incidence and prevalence, while Niger 35-90-57 performance demonstrates a stable decrease in the HIV epidemic. One possible explanation for the observed processes may have different development of the epidemic process in populations that differ by demographic characteristics. From this we can assume that the epidemic control in a strategy of «90-90-90» or any other strategies will differ significantly in such self-regulating systems.

Aim: modeling the dynamics of the epidemic process in populations with different probability of HIV transmission and negative, zero, positive population growth.

Materials and methods: Computer probabilistic modeling by the Monte Carlo method was carried out. The following parameters were used to describe the epidemic process: population size, birth rate, mortality, HIV prevalence, lethality among patients with HIV/AIDS and probability of HIV transmission. The values of these parameters were close to the UNAIDS global statistics. It is assumed that the effective management of the epidemic reduce the probability of HIV transmission in the population. The dynamics of the population size, incidence and prevalence of HIV infection in populations with negative, zero, positive natural growth and the probability of HIV transmission in the population from 50% to 10% has been consistently studied. Statistical processing carried out by the Student method.

Results and discussion. In populations with a negative population growth and a probability of HIV transmission of 0.5, incidence and prevalence at the initial stage are characterized by an increasing trend, reach peak values and decrease to zero. When reducing the probability of HIV transmission peak becomes plateau or directly take the downward shape. In general terms, similar patterns are recorded at zero population growth. The incidence and prevalence of HIV infection with a positive population growth are changing cyclically up and down. Change transmission probabilities range from 0.5 to 0.2 is characterized by a decrease in the frequency and amplitude of peaks increasing incidence and prevalence. When transmission probabilities at 0.1 epidemic process drops sharply. According to the simulation, any managerial impact in countries with negative population growth should be effective. Practical evidence does not contradict theory. For example, indicators "56-66-59" in Ukraine led to a decrease in the incidence. Management actions in populations with positive population growth that reduce the probability of HIV transmission by 20% or 40% are ineffective. When reaching 80%, the epidemic process abruptly stops.

Conclusions. The effect of reducing the probability of HIV transmission in populations with a negative and zero population growth is expressed as a linear reduction in incidence and prevalence (at fixed lethality). In populations with a positive natural growth reduction transmission probabilities less than 40% strategically not effective, and when it reaches 80% potentiated abrupt cessation epidemic process.

Insect bites and Lepidopterism are a major sensitization hazard for forestry workers. In recent years, different species of the genus Thaumetopoea are expanding their habitat in Bulgaria and represent a serious health threat for people working in the forests. The present epidemiological pilot study aims to investigate the specific sensitization of the forestry workers to the caterpillars of the most spread Thaumetopoea species in Bulgaria, as well as to evaluate their hypersensitivity to a range of inhalant, insect and food allergens.Thirty four forestry workers (28 men and 6 women) were surveyed. The sensitization to pine processionary (Thaumetopoea pityocampa); oak processionary (Thaumetopoea processionea) and Thaumetopoea solitaria was assessed by skin prick tests. Blood samples were taken for determination of total and allergen-specific IgE against a range of inhalant, insect and food allergens. Fourteen (41%) of the forestry workers reported skin rash, itching, runny nose and sneezing during their daily professional activities in the forest. Sixteen (47%) were sensitized to one or more representatives of the Thaumetopoeidae family. The most common is poly-sensitization to all three Thaumetopoea species - in 6 (38%), as well as mono-sensitization to pine processionary - in other 5 (31%). In 13 (39%) increased levels of total IgE, were found. A prevalence of insect allergy was also found. In conclusion, this pilot study provided important information on the impact of the different Thaumetopoea species on the health of the forestry workers. It also outlined the key role of different environmental allergens for the development of symptoms of IgE-mediated allergy and the need for more detailed epidemiologic and allergologic study on the medico-social importance of the sensitization to Thaumetopoea species.

Relevance. After vaccination against smallpox is completed, more than 50% of the population are not immune to pathogens of the genus Orthopoxvirus, which creates the risk of mass infection if the smallpox virus is used as a biological weapon.

Aim. To assess the correlations between humoral immunity, clinical signs during a vaccination period and, sex and age characteristics of vaccinia virus Practical Aspects of Epidemiology and Vaccine Prevention (VCV) recipients.

Materials and methods. We studied a vaccination clinical data of 82 subjects first vaccinated with a smallpox vaccine. Vaccinia neutralizing antibody titers were determined for 27 subjects using plaque reduction neutralization tests. According to antibody titers they were divided into groups of mild (25%), moderate (50%), and heavy reaction (25%).

Results. A total of 34% and 66% vaccine recipients experienced mild or moderate vaccination period, respectively. Among them 83% vaccine recipients experienced or local and systemic adverse events. Compared to mild group, moderate group had larger scab, hyperemia (p < 0,01) and pustules (p < 0,05). It was a tendency that men had smaller scabs, more rapid scab shedding and less intense hyperemia compared to women. In contrast to low and high neutralizing antibody titers, medium ones were associated with smaller local inflammation (induration zones, hyperemia, pustules).

Conclusion. The same vaccine and vaccination schedule may produce different protective neutralizing antibody levels and different humoral immunity in similar demographic groups. The underlying reasons need further research.

In recent years, there has been a steady increase in the number of infections specific to the perinatal period, wth 60% of the perinatal infections in St. Petersburg being intra-amniotic infections (IAI) of the fetus.

The aim of the study is to identify the frequency and risk factors of Intra-amniotic infection of fetus, not elsewhere classified (ICD-10 code P39.2).

Materials and methods. The study, conducted in a maternity hospital in St. Petersburg, included 240 newborns wth clinically established diagnoses from the P39 group «Other infections specific to the perinatal period».

Results of the study. A definition of the case of IAI of the fetus, not elsewhere classified (ICD-10 code P39.2), was proposed - the presence of IAI signs in the histological study of the placenta and the presence of a systemic inflammatory response in a newborn child. Using the definition of a confirmed case the frequency of fetal IAI was 0.42 per 100 children live-born, which is 3.5 times lower than the frequency of clinically determined diagnoses. Risk factors for the confirmed case were: asymptomatic bacteriuria, pyelonephritis, colpitis, tonsilltis, cervical erosion in the history of cervical anamnesis, cardiovascular diseases in the mother.

Conclusion. In the course of epidemiological surveillance of intra-amniotic infection of the fetus, it is necessary to use the definition of the case with further stratification of data on the newborn's body weight at birth. In order to reduce the incidence of this pathology, it is necessary to develop programs aimed at identifying and eliminating factors that increase the risk of maternal and fetal IAI.

Relevance. In surgical hospitals, outbreaks of purulent-septic infections (GSI) caused by Klebsiella pneumonia do often occur. The causes of such outbreaks generally remain insufficiently clear. The purpose of the work is an epidemiological diagnostics of group incidence by GSI clebsiellous etiology, which arose in cardiosurgical hospital.

Materials and methods. The analysis K. pneumonia eduction frequency and detection of purulent-septic infection Klebsiella etiology among patients of anaesthesiology and reanimation department and treatment departments of a cardiosurgical hospital in 10 months 2019 was carried out. Against the background of increased frequency of a bacteria carrying 13 strains of K. pneumonia were genotyped, their adhesive activity, ensitivity to 29 antibiotics and to three disinfectants (D) were studied.

Results. According to the results of agent genotyping, 5 epidemic centers of clebsiellous purulent-septic infection etiology with 11 cases of infection were detected. All K. rheumoniae strains found in epidemic focus were polyresistant to antibiotics and in 46.1% of cases resistant to Q.A.C. containing disinfectant. The circumstance of formation of related cases of purulent septic infection in certain epidemic centers was simultaneous stay of sick in anaesthesiology and reanimation department with the presence of common personnel.

Conclusion. The spread of infection in the conditions of anaesthesiology and reanimation department of the cardiac hospital most likely occurred because of a contact-household path involving intermediate factor of the transmission of the pathogen.