INFLUENZA VIRUS EPIDEMIOLOGICAL SITUATION IN THE SOUTH OF WESTERN SIBERIA IN 2011-2012

In the result of the monitoring for influenza in the Novosibirsk region during the season 2011-2012 85 strains of influenza virus on the culture of MDCK cells were isolated: 79 strains A (H3N2) and 6 strains of influenza virus B (five strains belonged to the Yamagata line and. 1 strain belonged to the Victoria line). During the entire epidemic season 2011-2012 on the territory of the Novosibirsk region no strains of influenza A (H1N1) pdm09 were allocated. For molecular genetic analysis 3 strains of influenza A (H3N2) were selected. We determined full nucleotide sequence of NA and. HA genes encoding respective surface glycoproteins of influenza virus, as well as the comparative analysis of amino acid sequences of these proteins to the strains of influenza A (H3N2), vaccine strain and. the strain A/Victoria/361/2011 earlier seasons, for which diagnostic serum were obtained

Humoral immunity to influenza and severe influenza cases in Russia in 2018-2019

The aim of our work was to investigate the herd immunity to influenza viruses among population of Russia during autumn 2918; evaluation of severe cases of the infection over the season of2018-2019 epidemics, and confirmed cases of influenza in vaccinated persons. A total of 1835 samples of blood serum were studied. Neither sample did react in hemagglutination inhibition test with highly pathogenic A(H5N8) and A(H7N9) viral strains. 41 to 58% of samples, dependent on sampling region, showed significant antibody titers (> 40) against против вакцинного штамма the vaccinal A/Michigan/45/2015 strain (H1N1pdm09). 40 to 63% of the same sera were positive for epidemic A/Lipetsk/1V/2018 strain (H1N1pdm09), isolated at the start of epidemic season (26.11.2018). From 26 to 46% of the samples were seropositive towards vaccinal strain A/Singapore/ INFIMH-16-0019/2016 (H3N2), and 10 to 23% towards Yamagata influenza B genetic strain. Severe influenza cases during the 2018-2019 epidemic season were caused, mainly, by influenza A virus, with predominance of A/H1N1pdm09 (52.5%), with only 3% of cases caused by influenza A viruses. 217 cases of influenza with lethal outcome were confirmed, of them about a half of these cases (44.7%) affected older persons (> 60 years old), 29% were diagnosed in the group of 46-59 years old. Eight lethal cases of influenza infection (3.7%) were documented in the persons vaccinated before the vaccination season. Over 75% of patients with lethal influenza cases had concomitant diseases, with cardiovascular disorders, obesity, diabetes, urogenital diseases, infectious diseases (HIV, hepatitis) being most often. Hence, vaccination against influenza remains the most effective protective tool, especially in the risk groups. The study was performed in the frames of the state task contract (ГЗ-1/16 and ГЗ-2/18)

2019–2020 herd immunity to seasonal influenza viruses prior to epidemic season and rate of severe disease cases

The aim was to analyze heard immunity against influenza viruses as well as severe course of influenza infection prior to the 2019–2020 epidemic season. Methods. Blood sera samples were collected prior to and after conducting population-wide influenza vaccination campaign at the sanitary and epidemiological centers in different regions of the Russian Federation as well as at the Siberian Federal District, respectively. Sera samples were tested by using hemagglutination inhibition (HI) assay with vaccine strains A/Brisbane/02/2018 (H1N1)pdm09, A/Kansas/14/2017 (H3N2), B/Colorado/06/2017 (Victoria lineage). Baseline clinical and autopsy materials in case of influenza infection in vaccinated patients or severe and fatal influenza cases were collected to be tested by RT-PCR at the sanitary and epidemiological centers, Rospotrebnadzor. All influenza-virus positive samples were further sent to the SRC VB “Vector”. Results. A total of 7,896 and 600 blood serum samples were collected from subjects at Siberian Federal District prior to and after the populationwide influenza vaccination campaign, respectively. Prior to the epidemic season, the proportion of individuals seropositive for the influenza A virus subtypes A/(H1N1)pdm09 and A/H3N2 exceeded 50% in most of the regions, whereas frequency of those seropositive for the influenza B virus was profoundly lower ranging from 12 to 46% in the Northwestern Federal District and Volga Federal District, respectively. After influenza vaccination, the percentage of seropositive subjects in the Siberian Federal District increased as follows: for influenza subtype A/(H1N1)pdm09 — from 66 up to 79%, influenza subtype A/H3N2 — from 68 up to 78%, and for influenza B/Victoria — from 32 up to 47%. In 2019–2020, influenza B virus more frequently caused severe infection that agrees with the herd immunity data prior to the epidemic season. However, the vast majority of the influenza cases with fatal outcome was associated with influenza virus A A/H1N1pdm09 subtype. Conclusion. Quality of influenza vaccine, especially that one intended to vaccinate risk group subjects remains a crucial issue for contemporary scientific community. The study was conducted within the framework of the State Assignments no. 1/16 and 2/18

Investigation of the antiviral activity of the recombinant human interferon lambda 1 in human conjunctiva cell culture

The aim of the study was to determine the efficacy of recombinant human interferon lambda 1 (IFN-λ1) against human adenovirus serotype 5 in a culture of human conjunctival cells Chang conjunctiva clone 1-5c-4. Material and methods. The study design consisted of three experimental schemes, reflecting a prophylactic and two options for a therapeutic and prophylactic treatment regimen (with the constant presence of the virus in the culture medium and with its removal after adsorption). The antiviral activity of IFN-λ1 was determined by the number of viable cells after exposure to the virus (MTT test). Results and discussion. It has been established that IFN-λ1 has antiviral activity against human adenovirus in vitro under a prophylactic and therapeutic-prophylactic scheme of administration at an infection dose of 1 and 10 TCID50 (50% tissue culture infectious dose), but not at an infection dose of 100 TCID50. The antiviral effect of the use of IFN-λ1 in a therapeutic and prophylactic regimen at an infection dose of 1 TCID50 was comparable to that of IFN-α. At the same time, both interferons did not have a toxic effect on the cell culture even at a concentration of 84 and 58 mg/ml, respectively. The antiviral activity and the absence of cytotoxic action provide the basis for further study of the possibility of development of based on IFN-λ1 drug for eye conjunctiva viral diseases treatment

Cyclamen europaeum (<i>Cyclamen purpurascens</i>) extract as adjuvant for nasal immunization of mice with influenza antigens

The article describes the first attempt to use the juice and extract of Cyclamen europaeum (Cyclamen purpurascens) tubers as an adjuvant for intranasal immunization of mice with influenza antigens. The concentration of antigens used for immunization was 300 μg/ml for each subtype. The adjuvant was added at the concentration of 10 and 20 mg/ml. Blood serum was studied using the hemagglutination inhibition reaction (HI) and enzyme immunoassay (ELISA). After two immunizations with a dose of 7.5 μg, the maximum inverse titers to the H1/H3/B components in the HI were 320/80/80, respectively. The administration of an intranasal comparator without an adjuvant did not result in seroconversion which can be detected by the HI. The analysis of the blood sera of mice, immunized intranasally by the antigen only, showed no increase in the antibody levels between the first and second injections. For mice immunized intranasally by a preparation containing 10 mg/ml (0.5 mg per 50 μl dose) of adjuvant the ELISA detected a significant growth of antibody levels for all components, and GMT antibody levels were comparable to GMT antibody levels after a single intramuscular injection of 5 μg of each antigen. Despite a significant serum titer dispersion (which the authors explain by the impossibility of ensuring absolute uniformity in administration of 50 μl of substance via the nasal route) the use of the extract as an adjuvant for intranasal immunization of mice with highly concentrated influenza antigens showed a significant humoral response. The level of this response after two immunizations in some animals was comparable to that after intramuscular administration. The obtained data open the possibility of using Cyclamen europaeum tuber extract or its chemical analogues in further studies in guinea pigs, ferrets or other animal models in order to develop an efficacious adjuvant for intranasal immunization

ANALYSIS OF POPULATION IMMUNITY AGAINST INFLUENZA PRIOR TO 2014 AND 2015 EPIDEMIC SEASONS

Aim. Control for the population herd immunity against seasonal influenza viruses as well as for emergence of antibodies against influenza with pandemic potential in human blood sera. Materials and methods. HAI reaction against vaccine and epidemic influenza viruses as well as HPAI viruses A/rook/Chany/32/2015 (H5N1) (clade 2.3.2.1c.) andA/Anhui/01/2013 (H7N9). Results. Among all the sera samples collected in the autumn of 2014 and 2015, none had reacted in HAI against A(H5N1) and A(H7N9) antigens even at 1:10 dilution. Among samples collected in autumn 2014, 41% were positive to A/Califorrna/07/09(HlNlpdm09) virus, 36% - A/Texas/50/2012 (H3N2), 40% - B/Brisbane/60/2008 (Vict.lin.) and 47% reacted in HAI against the B/Massachusetts/2/2012 (Yam.lin.) strain. 22% of all the samples had a titer of at least 40 against all the antigens and only 10% in HAI had a titer of 40 or more against all the vaccine strains. Among the samples collected in autumn 2015, the number of seropositive against A/Califorrna/07/09(HlNlpdm09) varied from 31% in the Urals FD to 46% in the Southern FD. The amount of seropositive against A/Switzerland/9715293/13 (H3N2) strain was at the level of 4 - 13% in all the FDs except Urals, where this parameter was slightly above 30%. The amount of seropositive against vaccine influenza В viruses varied from 23 to 76%. Only 2% of sera had titers in HAI of 40 or above against all the vaccine strains, 29% of all the samples were seronegative. Conclusion. Population immunity in Russia against influenza A(H3N2) is at a very low level, thus socially significant consequences of influenza epidemics in many aspects will depend on the vaccination campaign of autumn 2016

SEVERE CASES OF SEASONAL INFLUENZA IN RUSSIA IN 2015 - 2016 AND 2016 - 2017

Aim. Evaluation of seroprevalence of antibodies to influenza A and В viruses and analysis of specimens from severe or fatal influenza cases in Russia in 2015 - 2016 and 2016 - 2017 flu seasons. Materials and methods. Determination of antibody titer in human serum samples in hemagglutination inhibition assay with reference antigens. Isolation of influenza viruses from nasopharyngeal swabs and autopsy material in cell culture. Characterization ofisolated strains. Results. In 2016, compared to 2015, the proportion of serum samples, containing antibodies to influenza viruses A(H 1N1 pdm09) and A(H3N2), increased. During the 2015-2016 season, elevated number of severe and fatal cases of influenza were registered. The majority of circulated strains belonged to the new clade 6B.1 of A(HlNippdm09 viruses. 1% of analyzed isolates carried H275Y amino acid substitution in neuraminidase and were resistant to oseltamivir. In the 2016 - 2017 season, there were less severe cases of influenza. The most prevalent were influenza viruses A(H3N2) and B/Victoria. Isolated H3N2 viruses belonged to the 3C.2a subclade and B/Victoria isolates were from the 1A genetic group. All tested strains were susceptible to neuraminidase inhibitors. Conclusions. Flu seasons 2015 - 2016 and 2016 - 2017 differed in intensity of influenza activity and in the dominant influenza A virus subtype. Immunization with vaccine, comprising new HlNlpdm09-component, is crucial for prophylaxis of influenza infection with viruses from 6B. 1 subclade in the next season. Neuraminidase inhibitors are recommended for influenza treatment

Экстракт цикламена европейского (Cyclamen purpurascens) в качестве адъюванта при интраназальной иммунизации мышей гриппозными антигенами

The article describes the first attempt to use the juice and extract of Cyclamen europaeum (Cyclamen purpurascens) tubers as an adjuvant for intranasal immunization of mice with influenza antigens. The concentration of antigens used for immunization was 300 μg/ml for each subtype. The adjuvant was added at the concentration of 10 and 20 mg/ml. Blood serum was studied using the hemagglutination inhibition reaction (HI) and enzyme immunoassay (ELISA). After two immunizations with a dose of 7.5 μg, the maximum inverse titers to the H1/H3/B components in the HI were 320/80/80, respectively. The administration of an intranasal comparator without an adjuvant did not result in seroconversion which can be detected by the HI. The analysis of the blood sera of mice, immunized intranasally by the antigen only, showed no increase in the antibody levels between the first and second injections. For mice immunized intranasally by a preparation containing 10 mg/ml (0.5 mg per 50 μl dose) of adjuvant the ELISA detected a significant growth of antibody levels for all components, and GMT antibody levels were comparable to GMT antibody levels after a single intramuscular injection of 5 μg of each antigen. Despite a significant serum titer dispersion (which the authors explain by the impossibility of ensuring absolute uniformity in administration of 50 μl of substance via the nasal route) the use of the extract as an adjuvant for intranasal immunization of mice with highly concentrated influenza antigens showed a significant humoral response. The level of this response after two immunizations in some animals was comparable to that after intramuscular administration. The obtained data open the possibility of using Cyclamen europaeum tuber extract or its chemical analogues in further studies in guinea pigs, ferrets or other animal models in order to develop an efficacious adjuvant for intranasal immunization.В статье описано первое использование сока и экстракта клубней цикламена европейского (Cyclamen purpurascens) в качестве адъюванта при интраназальной иммунизации мышей гриппозными антигенами. Для иммунизации использовали концентрацию антигенов 300 мкг/мл каждого субтипа. Адъювант добавлялся в концентрации 10 и 20 мг/мл. Сыворотки крови изучали в реакции торможения гемагглютинации (РТГА) и иммуноферментном анализе (ИФА). После двух иммунизаций дозой 7,5 мкг максимальные обратные титры к H1/H3/B-компонентам в РТГА составили 320/80/80 соответственно. Введение интраназального препарата сравнения без адъюванта не привело к сероконверсии, детектируемой в РТГА. В сыворотках крови мышей, иммунизированных интраназально препаратом сравнения без адъюванта, не отмечено достоверного нарастания уровня антител между первым и вторым введением. В группах, иммунизированных интраназально препаратом, содержащим 10 мг/мл (0,5 мг в 1 дозе, объемом 50 мкл) адъюванта, отмечено значимое нарастание уровня антител между однократной и двукратной иммунизацией для всех компонентов, детектированных в ИФА, а средние уровни антител сопоставимы с ответом, полученным на однократное внутримышечное введение дозы препарата, содержащей 5 мкг каждого антигена. Несмотря на разброс значений титров сывороток крови между животными, который мы связываем с невозможностью стандартного внесения 50 мкл препарата в носоглотку мыши, применение экстракта в качестве адъюванта при интраназальной иммунизации мышей высококонцентрированными гриппозными антигенами показало выраженный гуморальный ответ. Уровень этого ответа после двукратной иммунизации у некоторых животных сравним с ответом на гриппозные вакцины при внутримышечном введении. Полученные данные позволяют рассматривать сок и экстракт клубней цикламена европейского или его синтетические аналоги для дальнейших исследований на морских свинках, хорьках или других животных-моделях с целью разработки эффективного адъюванта для интраназальной вакцинации

Severe cases of seasonal influenza in Russia in 2017-2018.

The 2017-2018 influenza epidemic season in Russia was characterized by a relatively low morbidity and mortality. We evaluated herd immunity prior to the 2017-2018 influenza season in hemagglutination inhibition assay, and performed characterization of influenza viruses isolated from severe or fatal influenza cases and from influenza cases in people vaccinated in the fall of 2017. During the 2017-2018 epidemic season, 87 influenza A and B viruses were isolated and viruses of the 75 influenza cases, including selected viral isolates and viruses analyzed directly from the original clinical material, were genetically characterized. The analyzed A(H1N1)pdm09 viruses belonged to clade 6B.1, B/Yamagata-like viruses belonged to clade 3, and B/Victoria-like viruses belonged to clade 1A and they were antigenically similar to the corresponding vaccine strains. A(H3N2) viruses belonged to clade 3C.2a and were difficult to characterize antigenically and the analysis indicated antigenic differences from the corresponding egg-grown vaccine strain. The next generation sequencing revealed the presence of D222/G/N polymorphism in the hemagglutinin gene in 32% of the analyzed A(H1N1)pdm09 lethal cases. This study demonstrated the importance of monitoring D222G/N polymorphism, including detection of minor viral variants with the mutations, in the hemagglutinin gene of A(H1N1)pdm09 for epidemiological surveillance. One strain of influenza virus A(H1N1)pdm09 was resistant to oseltamivir and had the H275Y amino acid substitution in the NA protein. All other isolates were susceptible to NA inhibitors. Prior to the 2017-2018 epidemic season, 67.4 million people were vaccinated, which accounted for 46.6% of the country's population. Just before the epidemic season 33-47% and 24-30% of blood sera samples collected within the territory of Russia showed the presence of protective antibody titers against vaccine strains of influenza A and influenza B/Victoria-like, respectively. Mass vaccination of the population had evidently reduced the severity of the flu epidemic during the 2017-2018 influenza epidemic season in Russia