BackgroundEbola virus disease (EVD) is one of the most dangerous and lethal diseases affecting humans. There are several licensed vaccines against EVD, but it remains one of the priority diseases for research and development of effective vaccines.MethodsA double-blind randomized placebo-controlled trial was performed to evaluate safety and immunogenicity of rVSV- and rAd5-vectored vaccine GamEvac-Combi in healthy adults of both sexes between 18 and 60 years. Safety and immunogenicity were assessed during the observation period of 12 months. Immunogenicity was assessed with GP-specific ELISA, IFN-γ ELISA, and plaque pseudoneutralization assay.ResultsVaccinated participants showed marked GP-specific IFN-γ response at day 28 and neutralizing response at day 42 (GMT = 32.6, seroconversion rate 96.3%). GP-specific IgG antibody levels in vaccinated participants peaked at day 42 (GMT = 9345) and persisted for a year after vaccination (GMT = 650).ConclusionThe vaccine showed favorable safety profile and induced robust cell-mediated immune response and strong humoral immune response that lasts at least for a year from the start of vaccination.Clinical trial registrationClinicalTrials.gov, identifier NCT03072030; Pan African Clinical Trial Registry, identifier PACTR201702002053400.

The purpose of this work was to determine the characteristics of the circulation of various viral respiratory pathogens during the epidemic season 2022–2023 against the background of the ongoing evolutionary variability of SARS-CoV-2. Materials and methods. The article uses methods used in «traditional» and «hospital» epidemiological surveillance of acute respiratory viral infections. Results and discussion. The period from October 2022 to September 2023 was characterized by early and high activity of influenza A(H1N1)pdm09 virus, which was replaced by influenza B virus. The antigenic and genetic properties of strains were closely related to influenza vaccines viruses recommended by WHO experts for the current season. The effectiveness of influenza vaccines was confirmed (75.0%). All of the studied influenza A(H1N1)pdm09, A(H3N2) and B epidemic strais retained sensitivity to drugs with antineuraminidase activity. The structure and share of other ARVI pathogens have changed somewhat compared to the previous season: There was a tendency to increase the activity of HAdV and HMPV; almost equivalent activity of HRsV, HRV, HCoV and HBoV; and a decrease in HPIV activity. At the same time, the frequency of other ARVI pathogens did not reach the indicators of the pre-pandemic COVID-19 period. The rationale for updating the composition of influenza vaccines for the countries of the Northern Hemisphere in the 2023–2024 season is given.

Introduction. COVID-19 is characterized by a varied clinical course. The aim of the work was to identify associations of SNPs of hemostatic system genes with COVID-19. Materials and methods. DNA was isolated from patients (n=117) and healthy participants (n=104). All infected patients were divided into 3 groups, depending on disease severity assessment, which was appreciated by NEWS2. Another group consisted of participants, who had asymptomatic infection in the past. Determination of SNPs of the genes FGB (-455 G/A), FII (20210 G/A), FV (1691 G/A), FVII (10976 G/A), FXIIIA1 (103 G/T), ITGA2 (807 C/T), ITGB3 (1565 T/C), SERPINE1 (-675 5G/4G) were performed by PCR using the Genetics of Hemostasis kit (DNA-Technology, Russia). Results. In analyzed SNPs, no significant differences were detected between the group of infected patients and healthy participants. But significant association was revealed in gene SERPINE1 (-675 5G/4G), when patient groups, differing in the disease severity, were analyzed relative to the group of participants with asymptomatic infection (p=0.0381; p=0 .0066; p=0.0009). It was found, that as COVID-19 severity scores increased, the proportion of 5G allele of gene SERPINE1 decreased, and the proportion of the 4G allele increased (p=0.005; p=0.009; p=0.0005). Similar processes were observed for genotypes 5G/5G and 4G/4G. Discussion. The gene SERPINE1 (-675 5G/4G) is associated with the severity of COVID-19. Conclusion. For the first time, it was discovered that 5G/5G genotype of gene SERPINE1 (-675 5G/4G) can be a marker of a milder course of COVID-19, and the 4G/4G genotype as a more severe one.

BACKGROUND: This study was conducted to determine the characteristics of various viral respiratory pathogens spreading during the epidemic season 20212022 and the frequency of co-infection with SARS-CoV-2 and influenza. AIM: To assess the development of the influenza epidemic and frequency of cases of co-infection with respiratory pathogens in patients with acute respiratory viral infections between 2021 and 2022. MATERIALS AND METHODS: Traditional and hospital epidemiological surveillance methods for acute respiratory viral infections were used. RESULTS: The epidemic season of 20212022 was characterized by the early activity of the influenza A(H3N2) virus and the emergence and rapid spread of the omicron variant of SARS-CoV-2. The distribution of different respiratory pathogens during the epidemic season 20212022 was clearly traced: SARS-CoV-2 (18.8%) was predominant, followed by influenza viruses (10.6%) and pathogens of other acute respiratory viral infections (0.43.7%). With respect to influenza A (H3N2) and B viruses, the heterogeneity of their populations and drift variability in relation to vaccine strains were noted. DISCUSSION: The frequency of co-infection with various respiratory pathogens was low, i.e., it was no more than 0.1%according to traditional surveillance, and no more than 9.2% in the hospital surveillance. The rationale for updating the composition of influenza vaccines for the countries in the Northern Hemisphere for 20222023 season was identified. CONCLUSION: At present, early diagnosis of influenza is important given the availability of effective drugs with a direct mechanism of action for the prevention and treatment of this pathogen. Timely use of anti-influenza drugs will reduce the risks of a severe course, complications, and death, including co-infection with SARS-CoV-2.

Introduction. A significant increase in the incidence of pertussis in the world, including among adolescents and adults, the prevalence of mild forms of the disease and asymptomatic carrier of bacteria B. pertussis, and the resulting need for mass revaccination of different age groups determine the demand for new vaccines against B. pertussis. In N.F. Gamaleya Federal Research Center for Epidemiology and Microbiology, a live intranasal pertussis vaccine for the prevention of pertussis (GamLPV) has been developed. The GamLPV vaccine underwent preclinical studies that proved its safety and effectiveness in experiments on small laboratory animals and nonhuman monkeys. Safety of vaccine is shown in clinical studies on healthy volunteers.The aim of the study is to assess the immunogenicity of different doses of the drug GamLPV when first used in healthy volunteers.Materials and methods. The study was conducted as randomized placebo-controlled, blind trial with consistent volunteer inclusion and dose escalation. Study ID in clinicaltrials.gov database: NCT03137927 (A Phase I Clinical Study of a GamLPV, a Live Intranasal Bordetella Pertussis Vaccine). The following parameters of humoral and cellular immune responses were assessed in dynamics: levels of specific IgM, IgG and IgA antibodies in blood serum of volunteers and the number of cytokines interleukin-17, tumor necrosis factor-α, interferon-γ produced after specific induction in vitro of blood mononuclears of vaccinated volunteers. Dynamics of attenuated bacteria persistence in nasopharynx of vaccinated volunteers was evaluated.Results. Intranasal vaccination of volunteers with the drug Gam LPV resulted in the formation of a specific humoral (IgG and IgA) and cellular immune response. The dose-dependent nature of immunoglobulin and cytokine production was shown. Attenuated bacteria persisted for a long time in the nose/oropharynx of vaccinated volunteers.Discussion. Good tolerability of all tested doses of the drug justifies the choice for further investigation of a vaccine dose equal to 4 × 109 CFU. At the next stage, the safety and immunogenicity of two-time vaccination of volunteers will be studied.

Introduction. The increase in the incidence of whooping cough in children and adults of different age groups justifies the need for their revaccination and the development of new, acceptable for these purposes. This work is devoted to substantiating the design of a clinical trial and describing the results of a comparative study of the safety and tolerability of the drug "GamLPV" with two-fold intranasal administration to healthy adult volunteers using two methods. The choice of the scheme and method of administration of the drug is justified. The serological structure of the population of adults aged 18–40 years living in Moscow and the Moscow region is characterized.Aim. Determination of the safety and tolerability of the drug with a double intranasal administration of the vaccine by drip method and spraying through an actuator.Materials and methods. A randomized placebo-controlled trial included 50 healthy male and female volunteers aged 18 to 40 years who met the inclusion criteria. The volunteers were divided into 2 groups of 25 people: a drip method of administration and spraying through an "actuator". By both methods, the drug was administered twice with an interval of 60 days.Results and discussion. Serological analysis of the population of healthy volunteers at the prescreening stage justified the inclusion in the study of volunteers containing anti-pertussis antibodies in the blood (IgG ≤40 Ed/ml). A comparison of the results of preclinical studies on an experimental model of non-human monkeys and the first phase of a clinical study of GamLPV allowed us to propose two methods of double administration of the drug as a promising vaccination scheme for volunteers. A comparative randomized study shows the safety of using the proposed scheme for vaccination of adult volunteers.Conclusions. Both proposed methods of double administration can be used to plan a multicenter study to research the immunogenicity and protective activity of GamLPV.

Relevance. The long-term leadership of ARVI pathogens determines their significance in the damage caused to both health and the economy of the country. Aim. To identify the features of the structure of ARVI during the emergence and widespread spread of SARS-CoV-2. Materials and methods. The article uses methods used in epidemiological surveillance of acute respiratory viral infections. Results and discussion. The results of the diagnostic available ARVI pathogens monitoring during epidemic seasons 2018-2021 are presented. The tendency of greater engagement of aged group 15 y.o. and older in epidemic process by morbidity and hospitalization due to SARI was shown. 49 818 nasal swabs from patients with influenza infection, 36 044 – with ARVI and 59 062 – with SARS-CoV-2 were tested. The top three in the structure of ARVI were INF, HEV-D and HRSV (in the 2018–2019 season); INF, SARS-CoV-2 and HEV-D (2019–2020); SARS-CoV-2, HEV-D and HPIV/HCoV (2020–2021). The activity of viral pathogens also differed: for HPIV, HAdV, HEV-D, HMPV, a decrease in activity was noted during the appearance of SARS-CoV-2 (2019–2020) and some of its growth in the following season; in relation to HRSV and INF - a decrease in activity during the last two seasons, and for INF – extremely low activity in the 2020-2021 season; the activity of seasonal HCoV even increased slightly. The data of genetic analyses of SARS-CoV-2 positive samples showed the heterogeneity of its population with a representative of variants (Alfa, Delta) as well as endemic for Russia and Moscow variants only. The recommended composition of influenza virus vaccines for use in the 2021–2022 northern hemisphere influenza season and in the 2022 southern hemisphere influenza season are presented due to their drift changeability. Conclusions. SARS-CoV-2 was influenced by the activity of ARVI pathogens with the almost complete displacement of influenza viruses from the circulation in the period 2020–2021.

INTRODUCTION:The surveillance of influenza viruses in ARVI structure and study of their properties in epidemic season 2019-2020 in Russian Federation are actual for investigations due to tasks of Global Influenza Strategy initiated by WHO in 2019. MATERIAL AND METHODS:The data of epidemiological surveillance on influenza- and ARVI-associated morbidity and hospitalization in different age groups of population were analyzed; virological, genetic and statistical methods were used. RESULTS:Preschool children were involved in epidemic the most. Meanwhile, the highest rate of hospitalization was observed in patients of 18-40 years old. Influenza A(H1N1)pdm09 virus dominated in etiology of ARVI in hospitalized patients and pneumonia. The role of respiratory viruses in severe cases of pneumonia and bronchoalveolar syndrome in children was shown. The differences in spectrum of circulating viruses caused ARVI in different regions of Russia were found. Influenza A(H1N1)pdm09 and B/Victoria-like viruses were the main etiological agents that caused of epidemic; its activity among all ARVI was 7.3 and 8.0%, respectively. The differences in antigenic properties of influenza A(H3N2) and B epidemic strains compared to vaccine viruses were found. The populations of epidemic strains were presented by following dominant genetic groups: 6B1.A5/183P for A(H1N1)pdm09, 3С.2а1b+137F for A(H3N2) and V1A.3 line B/Victoria-like for B viruses. The good profile of epidemic strains susceptibility to anti-neuraminidase inhibitors has been saved. The most of the studied influenza strains had the receptor specificity characteristic of human influenza viruses. CONCLUSIONS:Obtained results identified the peculiarities of viruses caused the influenza and ARVI in epidemic season 2019-2020 in different regions of Russia. These results suggested the important role of influenza A(H1N1) pdm09 in severe cases and pneumonia in adults 18-40 years old. The continuing drift in influenza viruses was found, which, apparently, could not but affect the efficacy of vaccine prophylaxis and was also considered in the recommendations of WHO experts on the composition of influenza vaccines for the countries of the Northern Hemisphere in the 2020-2021 season.

Objective. Data of the clinical picture forms of the disease, management and diagnostic capabilities of patients with COVID-19 continue to be studied. Our study presents results from the analysis of clinical and laboratory parameters of patients with COVID-19 in the period May-June 2020, who were treated in an infectious diseases hospital in Moscow. Patients and methods. The analytical cohort included 444, 198 men, 246 women aged 18 to 95 years, who were identified with SARS-CoV-2 RNA. The severity of the disease was determined in accordance with the temporary clinical recommendations (version 6 effective April 28, 2020), NEWS. Results. The study of the clinical picture showed the variability of the spectrum of clinical manifestations of COVID-19. The most common symptoms were fever, weakness, myalgia, dry cough, shortness of breath, diarrhea. The severity of the infection was not associated with the patient's gender, but was significantly correlated with age and the presence of comorbid status, which included chronic lung diseases, obesity, diabetes mellitus, and cardiovascular diseases. Observations of patients with severe and extremely severe course revealed characteristic laboratory markers of severity. The main method of etiological diagnosis was the RT-PCR method for detecting SARS-CoV-2 RNA in the nasopharyngeal secret. To verify COVID-19, we used an additional PCR method, fecal testing for the detection of SARS-CoV-2 RNA. Key words: COVID-19, clinical features, risk factors, SARS-CoV-2 RNA, biological substrates

Introduction. Due to the growth of laboratory-confirmed cases of pertussis among adolescents and adults, the spread of latent form of disease and the identification of asymptomatic carriage of the pathogen, the need arose to create a new vaccine against B. pertussis. On the basis of N. F. Gamaleya Federal Research Center for Epidemiology & Microbiology, a pertussis vaccine, containing attenuated B. pertussus bacteria, was developed. The article presents data on a clinical trial of the first phase of the pertussis vaccine “GumGVK, live intranasal vaccine for the prevention of pertussis” in healthy volunteers. Based on the results of the study, data shows the safety and tolerability of the first intranasal vaccine using on humans.Aim. To Study the safety and tolerability of the vaccine "GamGVK, live vaccine for intranasal use for the prevention of whooping cough»Materials and methods. Volunteers who expressed a desire to participate in the study were informed about its goals and objectives, conditions and requirements for participants, including the criteria for their inclusion/exclusion from the study. After signing the informed consent, the volunteers were screened for their compliance with the inclusion criteria. Screening studies and safety assessment of the drug were performed on the basis of anamnesis, subjective complaints, assessment of vital signs, ECG, peak flowmetry, results of laboratory tests of urine and blood, enzyme immunoassay of blood serum, analysis of nasopharyngeal aspirates for the presence of pertussis pathogen DNA, results of physical examination.Results and discussion. The study involved 36 "healthy" volunteers aged 18–40 years. The average age of the volunteers was 26.2 ± 5.5 years. Not reliably identified AES associated with the use of GumGVK. None of the used doses of the drug led to the formation of local and General allergic reactions to intranasal administration of GumGVK.Conclusions. The drug GumGVK is safe for nasal use, has good tolerance.

Aim. Analysis of inflammation biomarkers using reverse transcription with real time PCR (RT-PCR-RT) and multiplex immunofluorescent analysis xMAP with magnetic beads for the influenza infection. Materials and methods. Analysis of nasopharyngeal swabs, lymphocytes and blood sera of 10 patients with influenza and 10 donors was performed during the first 2 days of the disease by means of RT-PCR-RT and xMAP using the kit «37-plex» (BioRad). Results.The influenza virus A was revealed in 4 samples, the influenza virus B — in 6 swabs without mixed infections with other respiratory viruses. Analysis of the interferons (IFN) showed IFNα gene expression activation in patients’ lymphocytes but both the detection rate and the concentrations of IFNβ, IFNγ and IFNλ RNA were similar for patients and healthy donors. Among 37 inflammation biomarkers the concentrations of 7 proteins were enhanced including IFNα2, cytokines of TNF family (APRIL and BAFF), their soluble receptors sTNF-R1 and sTNF-R2, protein osteopontin and IL10. The concentrations of the complex of glycoprotein gp130 with the soluble receptor IL6 gp130/sIL-6Rβ and the matrix metalloprotease ММР-1 were reduced in patients’ sera. The polarization coefficient PI=[IL10]/[IFNγ]=0.53 for influenza samples suggested Th1 immune response. Conclusion. At the early stage of the influenza infection IFNα gene expression activation along with the induction of TNF family cytokines (APRIL and BAFF), their receptors (sTNF-R1 and sTNF-R2) and osteopontin as well as the inhibition of the complex gp130/sIL-6Rβ and metalloprotease ММР-1 were shown. Th1 immune response regulated by IL10 resulted in the recovery of the patients without complications.

Objective. To identify the drift variability of influenza viruses during the period of epidemic rise in the incidence of acute respiratory viral infections in the period 2018-2019. The biological and molecular-genetic properties of epidemic strains isolated in certain territories of the Russian Federation were studied and compared with data from the countries of the Northern Hemisphere. Materials and methods. A range of laboratory diagnostic methods has been applied, including immune fluorescence, RT-PCR, sequencing, methods for determining sensitivity to influenza drugs and receptor specificity. Results and discussion. The proportion of influenza viruses was as follows: A (H1N1) pdm09 - 53 %, A (H3N2) - 46 %, B - about 1 %. Cases of severe acute respiratory infections have most often been associated with influenza A(H1N1) pdm09 virus. According to antigenic properties, isolated strains corresponded to the properties of vaccine viruses (A/Michigan/45/2015 - by 99.6 % and A/Singapore INFIMH-16-0019/2016 - by 86 %). The heterogeneity of influenza A virus strains population was revealed as regards individual mutations in hemaglutinin. The influenza B virus population was equally represented by both evolutionary lines (B/Victoria and B/Yamagata-like). Receptor specificity was favorable for the course and outcome of the disease. Among 70 studied epidemic strains, no strains resistant to anti-neuraminidase drugs, oseltamivir and zanamivir, were detected. The article presents WHO recommendations on the composition of influenza vaccines for the countries of the Northern Hemisphere for 2019-2020, provides data on cases of human infection with avian influenza viruses A(H5N1), A(H5N6), A(H7N9) and A(H9N2).

Relevance. Influenza viruses, having an extremely high variability of the genome and significant environmental plasticity, continue to maintain a potential threat to the biological safety of mankind. The purpose Aims of the work is to analyze the features of the epidemic season of2017-2018. Materials and methods . The collection of data on the incidence and laboratory diagnosis of influenza and ARVI was carried out in the framework of the epidemiological surveillance of the circulation of influenza viruses in the Russian Federation. The observation period was from 40 weeks (october) 2017 to 25 weeks (june) 2018. The typing of the isolates was performed in the reaction of inhibition of hemagglutination activity (HI) according to the standard technique with diagnostic sera to reference and epidemic influenza viruses. Results and discussion . The article presents the features of the influenza virus circulation n for the period from october 2017 to may 2018 in some territories of Russia, collaborating with D. I. Ivanovsky Institute of Virology. The epidemic season had its own peculiarities: delayed and long-term activity of three influenza viruses, the share participation of which was almost equal, with some dominance of the influenza A(H1N1)pdm09 virus by the end of the season. Morbidity rates for the total population were comparable with the last epidemic season, meantime the morbidity among schoolchildren was higher. The number of hospitalizations and lethal outcomes was lower and mostly was found in patients of 65 years and older. In patients with severe acute respiratory infection (SARI) influenza A(H1N1)pdm09 was detected more frequently (58%). The influenza A(H1N1)pdm09 and A(H3N2) viruses were antigenically similar to strains included in influenza vaccines, at the same time, 96% of the isolated strains of influenza B virus belonged to a different evolutionary line. Epidemic strains were sensitive to neuraminidase inhibitors, except for 5 strains of influenza A(H1N1)pdm09 virus, isolated from pregnant women. Conclusions. The activity of non- influenza ARI viruses was similar to preliminary epidemic seasons. Recommendations on the influenza vaccines composition for the Northern hemisphere for 2019-2020 season are presented as well.

The article presents the features of the influenza virus circulation for the period from October 2016 to May 2017 in some territories of Russia collaborating with the D.I. Ivanovsky Institute of Virology, Federal State Budgetary Institution "N.F. Gamaleya Federal Research Centre for Epidemiology and Microbiology", Ministry of Health of the Russian Federation. One of the 2016-2017 season's peculiarities in Russia and countries of the Northern hemisphere was the earlier start of an increase in ARD morbidity with peak indexes reached towards the end of December 2016 - January 2017. First, influenza A(H3N2) virus was predominant; then, it was followed by influenza B virus activity observed until the end of the season. The indexes of morbidity were higher than in the previous season, while the rates of hospitalization and mortality were lower, lethal cases being detected in persons 65 years old and older. Epidemic strains of influenza A(H3N2) virus belonged to 3c.2a genetic group, reference strain A/Hong Hong/4408/2014, and its subgroup 3c.2a1, reference A/Bolzano/7/2016, that are antigenically similar. Strains of influenza B virus were antigenically similar to the B/Brisbane/60/2008 vaccine virus. Strains were sensitive to oseltamivir and zanamivir. The share participation of non-influenza ARI viruses was similar to preliminary epidemic seasons. WHO has issued recommendations for influenza virus vaccines composition for 2017-2018 for the Northern hemisphere.

Serologic studies occupy a significant place in influenza diagnosis. The article presents an analysis of the developed experimental version of ELISA test-systems for the detection of specific antibodies to the virus influenza A(H1N1)pdm09, and their dynamics at different stages of infection as compared with those of the traditional HAI method. The study included 20 paired samples of serum from patients hospitalized at different stages of the disease with etiology associated with the influenza virus A(H1N1)pdm09. Two groups were formed on the basis of HAI data, which showed the presence or absence of significant growth of specific antibodies to the influenza virus A(H1N1)pdm09. The control group consisted of 20 serum samples from individuals without influenza but with chronic hepatitis C. To examine the virus specific antibody two types of ELISA test systems were used. The first system was intended for the detection of IgM to the influenza virus A(H1N1)pdm09; the second was used for revealing specific IgG. The study showed the accuracy and specificity of detectable IgM and IgG to the virus influenza A(H1N1)pdm09. The dynamics of specific IgG titers in 15 of the 20 pairs of sera was reliable. The increase in titers was more pronounced than in the HAI. IgM against influenza virus could be detected up to 10 days, although reliable dynamics of these antibodies was not detected in paired samples. The test system was specific for the determination of both IgG and IgM antibodies to the influenza virus A(H1N1)pdm09 and significantly more sensitive than HAI. Using this ELISA test system, it is possible to monitor the dynamics of IgG to this virus even in the absence of diagnostic increases in antibody titers in HAI.

In the 2015—2016 epidemic season, there were dominant influenza A(H1N1)pdm09 strains (over 90%) among the circulating influenza viruses in most countries of the Northern Hemisphere and in Russia. A study of the antigenic properties of influenza A(H1N1)pdm09 strains revealed no differences in those of vaccine virus. Sequencing showed that there were amino acid substitutions in hemagglutinin (receptor binding and Sa sites) and in the genes encoding internal proteins (PA, NP, M1, and NS1). The rise in the incidence in the Russian Federation, which was etiologically associated with influenza viruses, was registered in January-February 2016 with its maximum being observed at 4—5 weeks of 2016. Within the framework of the epidemiological surveillance of circulating influenza viruses in the Russian Federation, which was conducted by the WHO European Office, the D.I. Ivanovsky Institute of Virology, Honorary Academician N.F. Gamaleya Federal Research Centre for Epidemiology and Microbiology, Ministry of Health of Russia, and the Research Institute of Influenza, Ministry of Health of Russia, monitored at the Infectious Diseases Hospital One (IDH-1), Moscow Healthcare Department. Among 1491 examinees, influenza was verified in 104 (21.3%) adults, 208 (42.5%) pregnant women, and 177 (36.2%) children. Influenza A(H1N1)pdm09 was more often diagnosed in the age group of 15—40 years (63.7%); the proportion of influenza patients aged over 50 years increased (22.1%). Most adult patients had moderate influenza; pneumonia complicated the disease in 27.4%. Influenza in the pregnant women was complicated by pneumonia in 4.8% of cases. Influenza was more frequently diagnosed in infants and preschool children aged 0 to 3 years (42.9%), 4 to 6 years (41.2%), and older (15.9%), namely: 7—9 years (10%) and 10—12 years (5.9%). Influenza in the children was complicated by acute tonsillitis (19.4%) and varying degrees of laryngeal stenosis (12.4%). Bronchial obstructive syndrome developed in 2.5%, the rate of pneumonia was 6.2%. Antiviral therapy (AVT) in the early stages of the disease reduces the risk of its severity, the frequency of secondary complications, and the duration and degree of clinical symptoms of influenza. AVT with oseltamivir, zanamivir, imidazolyl ethanamide pentandioic acid (ingavirin), and interferon-a2b (viferon) has been performed in the patients hospitalized at Moscow IDH-1 in the 2015—2016 epidemic season.

The aim of this study was to monitor in-hospital influenza virus infection during 2015 – 2016 epidemic flu season. Methods. Influenza virus was searched in patients hospitalized to a clinical infectious diseases hospital with acute respiratory viral infection during 2015 – 2016 influenza seasonal growth period using real-time RT-PCR method. Influenza virus was isolated from nasal swabs and autopsy material using canine kidney cell line. Other laboratory methods used included complete blood count, blood chemistry, blood gas analysis, urinalysis, and chest X-ray examination. Results. We examined 1,491 patients (375 adults, 546 children, 570 pregnant women with early gestational age). The proportion of hospitalized patients with confirmed A / H1N1pdm09 influenza in January – February, 2016, was 91.3%. A / H3N2 influenza virus was diagnosed in 5.7%, influenza B virus was isolated in 1.2% of patients. Totally, influenza virus was detected in 35.2% of samples, of which 30.1% of samples were obtained from adults, 33.7% of samples were obtained from children, and 39.8% of samples were obtained from pregnant women. The prevalent patient’s age was 15 to 60 years (76.1%) in adults and 3 to 6 years in children. Moderate course of influenza with a high rate of hospital admission was seen more often and was similar to that of 2009 – 2010 epidemic season. Proportion of patients with flu complicated by pneumonia was higher than that in 2014 – 2015 epidemic season. Bilateral lung injury was diagnosed in 48.4% of patients. High mortality in ICU (46.4%) was due to delayed start of antiviral treatment and late admission to a hospital. Conclusion. In 2015 – 2016 epidemic flu season, higher morbidity, complications and poor outcomes were related to predominant infection of A – H1N1pdm09 influenza virus. Risk factors of complications and death were delayed care seeking, lack of modern antiviral medications and comorbidity.

This work describes the specific features of the influenza virus circulating in the period from October 2015 to March 2016 in 10 cities of Russia, the basic laboratories of CEEI at the D.I. Ivanovsky Institute of Virology "Federal Research Centre of Epidemilogy and Microbiology named after the honorary academician N.F. Gamaleya" of the Ministry of Health of the Russian Federation. The increase in the morbidity caused by influenza viruses was detected in January-February 2016. The duration of the morbidity peak was 4-5 weeks. The most vulnerable group included children at the age from 3 to 6; a high rate of hospitalization was also detected among people at the age of 15-64 (65%). In clinic symptoms there were middle and severe forms with high frequency of hospitalization as compared with the season of 2009-2010, but much higher in comparison with the season of 2014-2015. Some of the hospitalized patients had virus pneumonias, half of which were bilateral. Among these patients, 10% were children; 30%, adults. The mortality in the intensive care unit of the hospital was 46%. Almost all lethal cases were among unvaccinated patients in the case of late hospitalization and without early antiviral therapy. The predominance of the influenza A(H1N1)09pdm virus both in the Russian Federation and the major part of the countries in the Northern hemisphere was noted. The results of the study of the antigenic properties of influenza strains of A(H1N1)pdm09 virus did not reveal any differences with respect to the vaccine virus. The sequencing data showed the amino acid substitutions in hemagglutinin (receptor binding and Sa sites) and in genes encoding internal proteins (PA, NP, M1, NS1). Strains were sensitive to oseltamivir and zanamivir and maintained resistance to rimantadine. The participation of non-influenza ARI viruses was comparable to that in preliminary epidemic seasons.