The influenza epidemic in Russia during the 2014–2015 season

The goal of this study was to compare the data on the intensity of the influenza A(H3N2) and B epidemic (especially the death toll) in the 2014–2015 season with the previous epidemic of the 2013-2014 season. The data on weekly morbidity, hospitalization, deaths from influenza, and acute respiratory diseases in different age groups of inhabitants of 59 cities located in 7 Federal districts of the Russian Federation were collected using the database of the Research Institute of Influenza.Analysis of this data showed that the influenza epidemic in 2014-2015 began earlier (in December) compared to the epidemic of 2013-2014, and spread mainly from Europe through Russia to the East. The intensity of the epidemic of 2014-2015 was higher compared to the previous one. The epidemic was more prevalent by regions and cities and a wider engagement of different age groups (except children up to 2 years of age) was observed. At the peak of the epidemic, the morbidity level was higher, the average duration of the epidemic was longer, and the number of patients among cities’ inhabitants (especially among children 7-14 years of age and adults) was higher than in the previous season. The rates of hospitalization with influenza and acute respiratory viral infections (ARVI) among patients older than 65 years were also higher (1.4 times) as well as the frequency of hospitalization with a diagnosis of “influenza” (2.7 times) and the number of deaths from laboratory confirmed influenza (1.8 times).Although the influenza pandemic virus strain A(H1N1)pdm09 was not the main causative agent of the 2015 epidemic and was distributed sporadically it still remained the leading cause of deaths from influenza in the course of this epidemic (45.5% of all cases). The deaths associated with this strain were recorded only in the European part of Russian Federation.The goal of this study was to compare the data on the intensity of the influenza A(H3N2) and B epidemic (especially the death toll) in the 2014–2015 season with the previous epidemic of the 2013-2014 season. The data on weekly morbidity, hospitalization, deaths from influenza, and acute respiratory diseases in different age groups of inhabitants of 59 cities located in 7 Federal districts of the Russian Federation were collected using the database of the Research Institute of Influenza. Analysis of this data showed that the influenza epidemic in 2014-2015 began earlier (in December) compared to the epidemic of 2013-2014, and spread mainly from Europe through Russia to the East. The intensity of the epidemic of 2014-2015 was higher compared to the previous one. The epidemic was more prevalent by regions and cities and a wider engagement of different age groups (except children up to 2 years of age) was observed. At the peak of the epidemic, the morbidity level was higher, the average duration of the epidemic was longer, and the number of patients among cities’ inhabitants (especially among children 7-14 years of age and adults) was higher than in the previous season. The rates of hospitalization with influenza and acute respiratory viral infections (ARVI) among patients older than 65 years were also higher (1.4 times) as well as the frequency of hospitalization with a diagnosis of “influenza” (2.7 times) and the number of deaths from laboratory confirmed influenza (1.8 times). Although the influenza pandemic virus strain A(H1N1)pdm09 was not the main causative agent of the 2015 epidemic and was distributed sporadically it still remained the leading cause of deaths from influenza in the course of this epidemic (45.5% of all cases). The deaths associated with this strain were recorded only in the European part of Russian Federation

Эпидемия гриппа в России в сезон 2014–2015 гг.

The goal of this study was to compare the data on the intensity of the influenza A(H3N2) and B epidemic (especially the death toll) in 2014–2015 season with the previous epidemic of 2013-2014. The data on weekly morbidity, hospitalization, deaths from influenza and acute respiratory diseases in different age groups of inhabitants of 59 cities located in 7 Federal districts of the Russian Federation were collected using the database of the Research Institute of Influenza. Analysis of this data showed, that the influenza epidemic in 2014-2015 began earlier (in December), compared with the epidemic of 2013-2014, and spread mainly from Europe through Russia to the East. The intensity of the epidemic 2014-2015 was higher, compared to the previous one. The epidemic was more prevalent by regions and cities and wider engagement of different age groups (except children up to 2 years) was observed. At the peak of the epidemic the morbidity level was higher, the average duration of the epidemic was longer and the number of patients among cities inhabitants (especially among children 7-14 years of age and adults) was higher than in the previous season. The rates of hospitalization with influenza and ARI among patients older than 65 years were also higher (1.4 times) as well as frequency of hospitalization with a diagnosis of “influenza” (2.7 times) and the number of deaths from laboratory confirmed influenza (1.8 times). Although the pandemic influenza virus A(H1N1)pdm09, was not the main causative agent of the epidemic 2015, it still was the main cause of deaths from influenza (45.5% of all cases). In spite of influenza A(H1N1)pdm09 virus sporadic prevalence, deaths from it were reported only on the European part of territory of Russia.Целью работы было сравнение показателей интенсивности эпидемии гриппа, вызванной штаммами вирусов гриппа А(H3N2) и В, в сезон 2014–2015 гг. с предшествующей эпидемией 2013–2014 гг. Особое внимание уделено летальным исходам от гриппа. Использована база данных НИИ гриппа по еженедельной заболеваемости, госпитализации, летальным исходам от гриппа и ОРЗ в различных возрастных группах населения 59-ти наблюдаемых городов, расположенных в семи Федеральных округах Российской Федерации. По сравнению с эпидемией 2014 г. эпидемия гриппа в 2014–2015 гг. началась раньше (в декабре) и распространялась, в основном, с запада на восток – из Европы по территории России в восточном направлении. Показатели интенсивности эпидемии 2015 г., в сравнении с предыдущей, были выше в отношении распространенности по округам, городам и вовлеченности возрастных групп населения (кроме детей до 2-х лет). Показатели заболеваемости на пике эпидемии, средней продолжительности эпидемии, уровней заболеваемости населения в городах (особенно среди детей 7–14 лет и взрослого населения) были выше, чем в предыдущем сезоне. Участились и случаи госпитализации с гриппом и OPВИ среди лиц старше 65 лет (в 1.4 раза), среди госпитализированных повысилась доля больных с диагнозом «грипп» (в 2.7 раза) и число летальных исходов от лабораторно подтвержденного гриппа (в 1.8 раза). Штамм пандемического вируса гриппа, A(H1N1)pdm09, хотя и не был основным возбудителем эпидемии 2015 г., попрежнему стал основной причиной летальных исходов от гриппа (в 45.5% всех случаев); причем случаи смерти, ассоциированные с этим штаммом, регистрировали только на европейской территории России при спорадическом уровне его распространения

Features of Epidemic Process of Influenza and its Etiology in the Countries of the Northern and Southern Hemispheres in the Period of Circulation of Pandemic Virus A(H1N1)pdm09 (According to WHO)

Relevance. Influenza is characterized by global distribution and the difference in its seasonality in countries with temperate and tropical climates. The importance of studying antigenic variation of influenza viruses due to the fact that changes in the antigenic structure is an evolutionary mechanism of adaptation of the virus to ensure its survival and cause annual epidemics.Aims. The Aim of this study was to identify the peculiarities of the geographical spread of influenza (seasonal), etiology and the rate of antigenic variability of influenza viruses A and B.Materials and methods. Based on data from WHO Reference research centers, information was collected on circulating influenza virus strains from 1975 A(H3N2), 1977 A(H1N1)pdm09 and type B of the Yamagata and Victoria lines from 1987 to 2019, as well as data on the number of all identified influenza viruses and individual strains circulating in the Northern and Southern hemispheres from 2008 to 2018.Results and discussion. Analysis of the global spread of influenza, its etiology and antigenic variability of viruses, according to WHO, showed that the influenza A(H1N1)pdm09 virus was the main causative agent of epidemics and regional outbreaks in seasons of high influenza activity in all countries except the United States and Canada, where influenza A(H3N2) and B viruses dominated in countries with severe seasonality, the change of season led to a change in the etiology of influenza, and in tropical countries, the A(H1N1)pdm09 virus more often remained dominant in all seasons of the year.Conclusions. The pronounced seasonality of influenza in Northern countries and its absence in tropical countries, where regional outbreaks prevailed in all seasons of the year, were confirmed. Low antigenic variability of influenza A(H1N1)pdm09 strains was confirmed, and the highest – A(H3N2). Among influenza B strains in the Victoria line had less antigenic variability, because the duration of its circulation before the appearance of a new drift variant was longer than that of the Yamagata line. The tendency to increase the total duration of circulation of influenza viruses B/Victoria, A(H1N1)pdm09 and B/Yamagata due to increased circulation before the emergence of new drift variants is shown

Differences Depending on the Etiology of Influenza Epidemics in 2014-2017

The goal is to identify features of epidemic process of influenza depending on the etiology of epidemics to clarification of the forecast for future epidemics. Analysis of epidemics of influenza in Russia conducted according to the Federal center for influenza on morbidity, hospitalization and deaths from influenza in 59 Russian cities. The epidemic of influenza A(H1N1)pdm09 2015–16 different from the mixed epidemics of influenza (A(H3N2) and B) 2014–15 and 2016–17 high development rate, high incidence of influenza and ARI at its peak, the incidence of hospitalization with a diagnosis of «influenza» (14%) and high mortality among the infected (6,0 on 100000). The epidemic of influenza A(H3N2) and B started earlier (December). They had a longer duration and the incidence in the cities and in the country, but less than the incidence at the peak of the epidemic and the incidence of hospitalization with a diagnosis of «influenza» (7.5 and 7.3%) and smaller (8.6 and 20 times) the mortality from the influenza. In these epidemics among the dead was higher than the percentage of children under 14 years and persons over 65 years of age than in the influenza epidemic 2015–16. And among the deaths increased the proportion of persons with chronic lung disease and immunodeficiency, but decreased the proportion of individuals with obesity and diseases of the liver and kidneys. For the period from 2009 to 2017 the tendency to increase the intensity of influenza A(H3N2) epidemics was 2.4 times greater than the decrease in the intensity of epidemic of influenza A(H1N1)pdm09

The Impact of Influenza of Different Etiologies on other ARVI in Children and Adults in 2014 to 2016

To assess the relationship between the incidence of influenza and RS, Corona, Metapneumo, Adeno, Paragripp, Rhino and Boca-viral infections, a correlation analysis of cases of influenza and each infection in the age groups of 24 cities of the Russian Federation was carried out. The age structure of infections had significant differences. Among the adult population, influenza was more often detected, more than A(H1N1)pdm09 (61.4%), and ARVI of no influenza etiology – among children 0–2 years, especially Boca-viral and RS-viral (72.5% and 62.8%) infections. The proportion of adults was higher than children aged 3–6 years, with Corona, Rhino and Paragripp infections. The pronounced winter-spring season of influenza was confirmed. RS, Corona and Metapneumo viral infection had a shift at the spring, and Adeno, Paragripp, Boca and Rhino-viral infections – in the autumn. A direct positive correlation between the incidence of influenza in the population as a whole and RS, Corona, Metapneumo, Adeno and Paragripp was shown, but there was no significant correlation with Rhino and Bocaviral infections. The correlation between the adult population and influenza was higher (strong – in RS) and was detected earlier than in children. The duration of correlation with influenza depended on the etiology of ARVI, influenza etiology and age

Analysis of the Influenza Epidemic in 2016 and Pandemic in 2009 Based on Two National Centers of WHO in the Russian Federation

Goal of the work - comparison of the epidemic process in the epidemic of 2016 and during the 2009 pandemic in the cities of Russia. Comparative data of the incidence of influenza and acute respiratory viral infections, hospitalization and mortality in different age groups of children (0 - 2, 3 - 6 and 7 -14 years) and adults (15 - 64 and 65 years of age) from 59 cities collaborating with 2 National Centers for influenza to the WHO in Russia, for the period from the 2009 pandemic and epidemic 2016. For the epidemic of 2016, as the 2009 pandemic was characterized by mono etiology (influenza virus A(H1N1)pdm09, the simultaneous occurrence of the peak of the epidemic in all age groups, the same percentage admitted to hospital with a diagnosis of "influenza"; involvement of the adult population and school children in the cities. The epidemic of 2016 was different: less involvement of children up to 6 years, higher development rate, the spread on the territory of Russia - from the West to the East, shorter duration of the epidemic in the country (12 and 17 weeks) and in the cities by population average (4.6 and 6.8 weeks), less morbidity for the period of the epidemic in cities (5.4 and 8.5%) and the country (9.6 and 14.4%), greater frequency of hospitalization but lower mortality from influenza in an average of 1.7 times

Epidemiological Peculiarities of the Flu Epidemic of 2016 in St. Petersburg

To identify the peculiarities of manifestation of epidemic process of influenza in 2016, and causes high morbidity and mortality in St. Petersburg, a comparative analysis of the incidence of influenza and acute respiratory viral infections, hospitalization and mortality in children and adults during the epidemic of 2016 in St. Petersburg and other 58 the observed cities of the Russian Federation. The epidemic of 2016 in St. Petersburg from other cities were characterized by a greater intensity: the duration of the epidemic; the incidence of the population on the peak (at 1.9 and 1.3%), within the boundaries of the epidemic in the city (7.7 and 5.4%) and the country (11.9 and 9,6%); shares admitted to hospital with a diagnosis of «influenza» among the whole population (17.1 and 14,0%); greater mortality from influenza among the whole population (3.3 tims), persons 15 - 64 (in 3 times) and 65 years and older (2.8 times). The low level of population immunity in Saint-Petersburg in the before the epidemic period and lower frequency of hospitalization of patients with influenza and ARVI among the population as a whole (2.4% and 3.6 percent), particularly children and persons over 65 years of age (2 times), could be the cause of high morbidity and mortality from influenza in St. Petersburg

The Epidemiological Situation of Influenza in the World and Russia in the Season 2014 – 2015

Comparison of spatial-temporal spread of influenza in the Northern and southern hemispheres according to the WHO and the analysis of the epidemic of influenza in Russia in the 2014 – 2015 season, according to the research Institute of influenza on the incidence of influenza and ARI in 59 cities of Russia.It is shown that in the season 2014 – 2015 in the Northern hemisphere, the intensity of the epidemics was higher in North America and Europe than East Asia and North Africa. In the Southern hemisphere have experienced low influenza activity. In the etiology of epidemics in countries of both hemispheres was dominated by influenza A(H3N2) and influenza B. The proportion of influenza A(H1N1)pdm09 was less in the Southern hemisphere was higher than in Northern countries. The incidence of influenza A(H3N2) in the Northern hemisphere was predominantly linked to the new strain A/Switzerland/9715293/2013 (H3N2), differing from the vaccine. In Europe, the majority of circulating influenza B strains were related to the strain B/Phuket/3073/2013, did not match the vaccine.In Russia the intensity of the influenza epidemic in 2015, was more than the previous epidemic of 2014, the prevalence in the cities, the morbidity especially children 7 – 14 years of age and adult population, the incidence of hospitalization with a diagnosis of «influenza» and the number of deaths

Влияние путей распространения эпидемий гриппа по территории России на особенности эпидемического процесса в различных федеральных округах

Aims. Show the ways of spreading influenza epidemics across the territory of Russia over a long period (1968–2019) and their influence on the incidence of influenza and ARVI in total and separately influenza A (H1N1), A (H3N2) and B in the Federal Districts in the period from 2009 to 2019.Materials and methods. The analysis of influenza epidemics was carried out according to the computer database of the National center for influenza.Results. A retrospective analysis of influenza epidemics shows the absence of inter-epidemic seasons after 1986, the increase in epidemics of mixed etiology and different routes of entry and spread of influenza viruses in Russia. During the circulation of the influenza A (H1N1)pdm09 virus, influenza epidemics were mainly of mixed etiology. The main causative agents of epidemics entered the territory of Russia more often from the west and in both ways, and from the west and from the east. In the next season, the main pathogen changed, and the path of the virus circulating in the previous season also changed. Influenza viruses of different types A and B usually diverged in time. Influenza viruses of the same type A, but of different subtypes, usually spread in different directions, with one of them having a limited distribution in the districts. The tendency of greater intensity of the epidemic process in the districts involved in the epidemic first is shown.Conclusions. 2009 to 2019 the incidence was higher in the Northwestern and Ural districts of the European part of Russia. One of the reasons for the high morbidity in these districts is the predominance of the western route of influenza viruses entering the territory of Russia and the high intensity of the epidemic process in the districts that were the first to be involved in the epidemic. Цель. Показать пути распространения эпидемий гриппа по территории России за многолетний период (1968–2019 гг.) и влияние их на заболеваемость гриппом A(H1N1), A(H3N2) и В и заболеваемость гриппом и острыми респираторными вирусными инфекциями в сумме в федеральных округах в период с 2009 по 2019 г.Материалы и методы. Анализ эпидемий гриппа проведен по данным компьютерной базы Национального центра по гриппу.Результаты. При ретроспективном анализе эпидемий гриппа показано отсутствие межэпидемических сезонов после 1986 г., учащение эпидемий смешанной этиологии, разных путей поступления и распространения вирусов гриппа на территории России. В период циркуляции вируса гриппа A(H1N1)pdm09 эпидемии, в основном, были смешанной этиологии. Основные возбудители эпидемий поступали на территорию России чаще с запада или обоими путями: и с запада, и с востока. В следующем сезоне происходила смена основного возбудителя, при этом изменялся и путь распространения вируса, циркулировавшего в предыдущем сезоне. Вирусы гриппа разных типов А и В обычно расходились во времени. Вирусы гриппа одного типа А, но разных подтипов, обычно распространялись в разных направлениях, при этом один из них имел ограниченное распространение по округам. В округах, вовлеченных в эпидемию первыми, была больше интенсивность эпидемического процесса.Заключение. С 2009 по 2019 г. заболеваемость была больше в Северо-Западном и Уральском округах европейской части России. Одной из причин высокой заболеваемости в этих округах является преобладание в этот период западного пути поступления вирусов гриппа на территорию России и большая интенсивность эпидемического процесса в округах, вовлеченных в эпидемию первыми.