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

Influenza Epidemiology And Influenza Vaccine Effectiveness During The 2016-2017 Season In The Global Influenza Hospital Surveillance Network (Gihsn)

BackgroundThe Global Influenza Hospital Surveillance Network (GIHSN) aims to determine the burden of severe influenza disease and Influenza Vaccine Effectiveness (IVE). This is a prospective, active surveillance and hospital-based epidemiological study to collect epidemiological data in the GIHSN. In the 2016-2017 influenza season, 15 sites in 14 countries participated in the GIHSN, although the analyses could not be performed in 2 sites. A common core protocol was used in order to make results comparable. Here we present the results of the GIHSN 2016-2017 influenza season.MethodsA RT-PCR test was performed to all patients that accomplished the requirements detailed on a common core protocol. Patients admitted were included in the study after signing the informed consent, if they were residents, not institutionalised, not discharged in the previous 30days from other hospitalisation with symptoms onset within the 7days prior to admission. Patients 5years old or more must also complied the Influenza-Like Illness definition. A test negative-design was implemented to perform IVE analysis. IVE was estimated using a logistic regression model, with the formula IVE=(1-aOR)x100, where aOR is the adjusted Odds Ratio comparing cases and controls.ResultsAmong 21,967 screened patients, 10,140 (46.16%) were included, as they accomplished the inclusion criteria, and tested, and therefore 11,827 (53.84%) patients were excluded. Around 60% of all patients included with laboratory results were recruited at 3 sites. The predominant strain was A(H3N2), detected in 63.6% of the cases (1840 patients), followed by B/Victoria, in 21.3% of the cases (618 patients). There were 2895 influenza positive patients (28.6% of the included patients). A(H1N1)pdm09 strain was mainly found in Mexico. IVE could only be performed in 6 sites separately. Overall IVE was 27.24 (95% CI 15.62-37.27. Vaccination seemed to confer better protection against influenza B and in people 2-4years, or 85years old or older. The aOR for hospitalized and testing positive for influenza was 3.02 (95% CI 1.59-5.76) comparing pregnant with non-pregnant women.ConclusionsVaccination prevented around 1 in 4 hospitalisations with influenza. Sparse numbers didn't allow estimating IVE in all sites separately. Pregnancy was found a risk factor for influenza, having 3 times more risk of being admitted with influenza for pregnant women.Wo