Influenza epidemiology and influenza vaccine effectiveness during the 2014–2015 season: annual report from the Global Influenza Hospital Surveillance Network

Abstract

The Global Influenza Hospital Surveillance Network (GIHSN) has established a prospective, active surveillance, hospital-based epidemiological study to collect epidemiological and virological data for the Northern and Southern Hemispheres over several consecutive seasons. It focuses exclusively on severe cases of influenza requiring hospitalization. A standard protocol is shared between sites allowing comparison and pooling of results. During the 2014–2015 influenza season, the GIHSN included seven coordinating sites from six countries (St. Petersburg and Moscow, Russian Federation; Prague, Czech Republic; Istanbul, Turkey; Beijing, China; Valencia, Spain; and Rio de Janeiro, Brazil). Here, we present the detailed epidemiological and influenza vaccine effectiveness findings for the Northern Hemisphere 2014–2015 influenza season.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-016-3378-1) contains supplementary material, which is available to authorized users.

Clinical characteristics and severity of influenza infections by virus type, subtype, and lineage: A systematic literature review

“…Concerning the frequency of complications and underlying conditions (Table ), we also found very few significant differences between the influenza viruses in the unadjusted virus comparisons. There was some evidence that A(H1N1)p may result in more complications compared to other influenza virus (sub)types: People infected with A(H1N1)p more often had pneumonia and were more frequently admitted in the ICU compared to influenza B, and more frequently had upper respiratory tract infections, pneumonia, and ICU admissions compared to A(H3N2).…”

“…An overview of the studies (Table and Table ) showed a lot of diversity in the populations that were investigated: Studies are presented in terms of hospitalized patients (n = 22) or cover mainly outpatient settings (n = 19), such as primary care (n = 6) or community‐based (n = 4) settings. Most studies were carried out in Asia (n = 17), Europe (n = 15), or North America (n = 8).…”

“…The influenza viruses that were most frequently compared were A(H1N1)p versus A(H3N2) (n = 23), influenza A versus B (n = 18), and A(H1N1) versus A(H3N2) (n = 12). The proportion of influenza patients that had received the vaccine was reported in 24 studies, but RR estimates were adjusted for vaccination status in only four papers . Vaccinated patients were excluded from the analyses in four studies, and no or insufficient information on patients’ vaccination status was available in 19 studies.…”

Influenza A and B in a cohort of outpatient children and adolescent with influenza like-illness during two consecutive influenza seasons

“…During the 20-month period of the study, we hypothesized that 1,200 cases of febrile syndrome followed by respiratory symptoms would occur, of which 5% would be influenza with virological confirmation. 9 Thus, at least 60 cases of proven influenza infection would be available for analysis.…”

Broad-Based CD4+ T Cell Responses to Influenza A Virus in a Healthy Individual Who Lacks Typical Immunodominance Hierarchy

“…Each year, about half a billion human beings have symptomatic influenza illness (1), and three to five million subjects suffer from severe influenza, causing approximately half a million deaths annually worldwide (2). Frequent mutation in hemagglutinin and neuraminidase of the circulating viruses and the mismatch between the circulating and vaccine viruses significantly affected the effectiveness of antibody-based vaccine strategy (3). Novel vaccines that are more effective and covering a broader spectrum of influenza viruses are urgently needed.…”