The influenza epidemic in Russia in 2014–2015 season (original) (raw)
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Background: Information on influenza-associated mortality in Russia is limited and largely related to deaths with influenza in the diagnosis that represent a small fraction of all influenza-associated deaths. Methods: Using previously developed methodology (Goldstein et al., Epidemiology 2012), we regressed the monthly rates of mortality for respiratory causes, as well as circulatory causes (available from the Russian Federal State Statistics Service (Rosstat)) during the 2013/14 through the 2018/19 influenza seasons linearly against the monthly proxies for the incidence of influenza A/H3N2, A/H1N1 and B (obtained using data from the Smorodintsev Research Institute of Influenza (RII) on influenza/ARI consultations, testing of respiratory specimens and genetic/antigenic characterization of influenza viruses), adjusting for the baseline rates of mortality not associated with influenza circulation and temporal trends. Results: For the 2013/14 through the 2018/19 seasons, influenza circulation was associated with an average annual 17636 (95% CI (9482,25790)) deaths for circulatory causes and 4179 (3250,5109) deaths for respiratory causes, with the largest number of deaths (32298 (18071,46525) for circulatory causes and 6689 (5019,8359) for respiratory causes) estimated during the 2014/15 influenza season. Influenza A/H3N2 was responsible for 51.8% of all circulatory influenza-associated deaths and 37.2% of all respiratory influenza-associated deaths. Influenza A/H1N1 was responsible for 23.4% of all circulatory influenza-associated deaths and 29.5% of all respiratory influenza-associated deaths. Influenza B was responsible for 24.9% of all circulatory influenza-associated deaths and 33.3% of all respiratory influenza-associated deaths, with the overwhelming majority of those deaths being caused by the B/Yamagata viruses. Compared to the 2013/14 through the 2015/16 seasons, during the 2016/17 through the 2018/19 seasons (when levels of influenza vaccination were significantly higher), the volume of influenza-associated mortality declined by about 16.1%, or 3809 annual respiratory and circulatory deaths. Conclusions: Influenza circulation is associated with a substantial mortality burden in Russia, particularly for circulatory deaths, with some reduction in mortality rates observed following the major increase in influenza vaccination coverage. Those results support the potential utility of further extending the levels of influenza vaccination, the use of quadrivalent influenza vaccines, and extra efforts for protecting individuals with circulatory disease in Russia, including vaccination and the use of antiviral medications.
American Journal of Infectious Diseases, 2013
Exchange of information on and sharing of influenza viruses through the GISRS network has great significance for understanding influenza virus evolution, recognition of a new pandemic virus emergence and for preparing annual WHO recommendations on influenza vaccine strain composition. Influenza surveillance in Russia is based on collaboration of two NICs with 59 Regional Bases. Most epidemiological and laboratory data are entered through the internet into the electronic database at the Research Institute of Influenza (RII), where they are analyzed and then reported to the Ministry of Public Health of Russia. Simultaneously, data are introduced into WHO's Flu Net and Euro Flu, both electronic databases. Annual influenza epidemics of moderate intensity were registered during four pre-pandemic seasons. Children aged 0-2 and 3-6 years were the most affected groups of the population. Influenza registered clinically among hospitalized patients with respiratory infections for the whole epidemic period varied between 1.3 and 5.4% and up but to 18.5-23.0% during the peak of the two pandemic waves caused by influenza A(H1N1) pdm 09 virus and to lesser extent (2.9 to 8.5%) during usual seasonal epidemics. Most epidemics were associated with influenza A(H1N1), A(H3N2) and B co-circulation. During the two pandemic waves (in 2009-2010 and 2010-2011) influenza A(H1N1) pdm 09 predominated. It was accompanied by a rapid growth of influenza morbidity with a significant increase of both hospitalization and mortality. The new pandemic virus displaced the previous seasonal A(H1N1) virus completely. As a rule, most of the influenza viruses circulating in Russia were antigenic ally related to the strains recommended by WHO for vaccine composition for the Northern hemisphere with the exception of two seasons when an unexpected replacement of the influenza B Victoria lineage by Yamagata lineage (2007-2008) and the following return of Victoria lineage viruses (2008-2009) was registered. Influenza surveillance in Russia was improved as a result of enhancing capacity to international standards and the introduction of new methods in NICs such as rRT-PCR diagnosis, regular testing of influenza viruses for susceptibility to antivirals, phylogenetic analysis as well as organization of sentinel surveillance in a number of Regional Base Laboratories. Improvements promoted rapid recognition of the appearance a new pandemic virus in the country and enhancement of confirmation tests in investigation of influenza related death cases.
Virologica Sinica, 2011
The aim of the work is the comparison of the epidemiology of influenza and acute respiratory virus infections (ARVI) in the Republic of Kazakhstan with the corresponding influenza epidemic in Russia induced by influenza pandemic virus A/California/07/2009 in 2009. Data on influenza and ARVI from the Republic of Kazakhstan and Federal Center of influenza was collected and investigated over the course of several weeks from hospitalized patients with the same diagnosis among all population and in age groups on 16 territories of Kazakhstan and in 49 major cities of Russia. The epidemic in Kazakhstan resembled the Russian epidemic in terms of its abnormally early beginning, expression of monoaetiology, the spread of the epidemic into all territories and start of the epidemics among adult population. High percentage of hospitalized people and lethal outcome were registered in this epidemic. Similarity of epidemic process character in corresponding border-line territories of both countries was found out. The epidemic in Russia was first recorded between 21st to 27th of September 2010 in South Sakhalin and cases were recorded in Kazakhstan three weeks later (October 16-22, 2010) in the north-east territories at the border of Siberia and Ural. The same as in Russia epidemic in Kazakhstan spread westward and southward.
Central European Journal of Public Health, 2016
Aim: Influenza virological surveillance is an essential tool for studying the evolution of influenza viruses as well as for annual updating of the vaccine composition. The aim of the present study is to analyse the circulation of the influenza viruses in Bulgaria during the four recent postpandemic seasons. Methods: A total of 3,681 respiratory samples from patients with influenza like illness (ILI) or acute respiratory illness (ARI) were tested for influenza viruses using Real Time RT-PCR. Results: Influenza viruses were detected in 1,367 (37%) samples. Of those viruses, 941 (69%) were of type A and 426 (31%) of type B. Among the subtyped A viruses, 543 (60%) were A(H1N1)pdm09 and 369 (40%) A(H3N2). Co-circulation of all seasonal influenza types/subtypes was registered during each season, with the exception of A(H1N1)pdm09 virus in the 2011/12 season. In this study, data gathered from the antigenic and genetic analyses of influenza viruses, their antiviral susceptibility, and the epidemiological and clinical characteristics of the infections are presented. Conclusions: Yearly variations in the distribution and frequency of influenza types/subtypes and an annual shift of the predominant type/subtype were observed. In the seasons with predominant spread of A(H1N1)pdm09 virus-2010/11 and 2013/14, a greater number of influenza-related pneumonia cases, ICU admissions and fatal cases was registered (p < 0.05). The results of the present study confirm the need for continuous and comprehensive influenza surveillance.
Risk factors for severe influenza a virus infections in post-2009 pandemic period
Srpski arhiv za celokupno lekarstvo, 2016
Introduction. Literature data concerning risk factors for severe influenza in post-2009 pandemic period, from low- and middle-income Central and Eastern European countries are very limited. Objective. The aim of this study was to investigate the risk factors for severe A(H1N1)pdm09 and A(H3N2) influenza during the post-2009 pandemic period. Methods. During four consecutive seasons of 2010/2011-2013/2014, nasopharyngeal or nasal and pharyngeal swab samples from 153 patients with mild and 147 patients with severe influenza were tested using real-time reverse transcription polymerase chain reaction (real-time RT PCR) assays. Results. The study indicated three statistically significant risk factors of influenza severity, including presence of chronic underlying illness/condition [odds ratio (OR) of 15.2, 95% confidence interval (CI) of 1.8-125.4, p = 0.001), age ?15 years (OR 9.2, 95% CI 3.5-24.1, p < 0.001), and delay in medical care of more than two days after the symptoms onset (O...
Surveillance of influenza in Finland during the 2009 pandemic, 10 May 2009 to 8 March 2010
Eurosurveillance, 2011
The first infection caused by pandemic influenza A(H1N1)2009 virus was confirmed in Finland on 10 May 2009. The spread of the disease and its impact were monitored using several surveillance systems, such as the national infectious disease register, notifications of clusters of influenza, influenza-like or influenza-related illnesses, as well as virological, hospital, case-based and mortality surveillance. The epidemic started in early October in the north and then spread to the south about two weeks later. Based on the data from laboratory-confirmed cases, the morbidity was highest in children. The daily number of patients hospitalised with influenza A(H1N1)2009 reached a maximum of over 400 in late November. Of the 1,580 hospitalised patients (median age 32 years), 672 (43%) had at least one chronic underlying illness, 35 (2%) were pregnant, 132 (8%) were treated in intensive care units and 74 (5%) required mechanical ventilation. The median age of patients admitted to intensive c...
Influenza A(H1N1)pdm09 and postpandemic influenza in Lithuania
Open Medicine, 2016
The objective of this study is to describe the clinical and epidemiological characteristics of patients hospitalized in Lithuania who are infected with influenza A(H1N1)pdm09 and to compare pandemic A(H1N1) pdm09 infection with postpandemic.In total, 146 subjects hospitalized with influenza A(H1N1) pdm09 were identified from 2009–2011. There were 53 during the initial pandemic wave in the summer of 2009, 69 during the peak pandemic period, and 24 during the “postpandemic” period that we included in this study. There were 22 subjects who died after laboratory confirmation of influenza A(H1N1)pdm09.No deaths were documented during the first wave. Subjects presenting during the peak of pandemic influenza had a greater incidence of fever (100% vs 77.4%; p<0.001), dry cough (95.7% vs 82.7%; p=0.01), and vomiting (26.1% vs 1.9%, p<0.001) as compared with patients infected during the first wave. The rate of bacterial pneumonia was 18.8% (13/69) during the peak pandemic period and 12....