Analytical performance of the BD veritor (TM) system for rapid detection of influenza virus A and B in a primary healthcare setting

Background: Infections with influenza A virus cannot be clinically differentiated from infections caused by influenza B virus or other respiratory viruses. Additionally, although antiviral treatment is available for influenza A virus, it is not effective for the other viruses and must be initiated early in the course of disease for it to be effective. For these reasons, there is a need for a rapid, accurate diagnostic test for use in physicians' offices at the time patients are seen. We report the first field performance of BD Veritor (TM) System for Rapid Detection of Flu A + B test compared to real time PCR. The performance of this test was compared to real time PCR performed in the Istanbul University Influenza Reference Laboratory

Influenza surveillance in Western Turkey in the era of quadrivalent vaccines: A 2003-2016 retrospective analysis

Human influenza is predominantly caused by influenza A virus (IAV) - A/H1N1 and/or A/H3N2 - and influenza B virus (IBV) - B/Victoria and/or B/Yamagata, which co-circulate each season. Influenza surveillance provides important information on seasonal disease burden and circulation, and vaccine content for the following season. To study the circulating influenza subtypes/lineages in western Turkey. Community-based sentinel surveillance results during 2003-2016 (weeks 40-20 each season; but week 21, 2009 through week 20, 2010 during the pandemic) were analyzed. Nasal/nasopharyngeal swabs from patients with influenza-like illness were tested for influenza virus and characterized as A/H1N1, A/H3N2, or IBV. A subset of IBV samples was further characterized as B/Victoria or B/Yamagata. Among 14,429 specimens (9,766 collected during interpandemic influenza seasons; 4,663 during the 2009-2010 pandemic), 3,927 (27.2%) were positive. Excluding the pandemic year (2009-2010), 645 (27.4%) samples were characterized as A/H1N1 or A/H1N1/pdm09, 958 (40.7%) as A/H3N2, and 752 (31.9%) as IBV, but the dominant subtype/lineage varied widely each season. During the pandemic year (2009-2010), 98.3% of cases were A/H1N1/pdm09. IBV accounted for 0-60.2% of positive samples each season. The IBV lineages in circulation matched the vaccine IBV lineage >50% in six seasons and <50% in four seasons; with an overall mismatch of 49.7%. IBV cases tended to peak later than IAV cases within seasons. These results have important implications for vaccine composition and optimal vaccination timing. Quadrivalent vaccines containing both IBV lineages can reduce B-lineage mismatch, thus reducing the burden of IBV disease

Evaluation of Sentinel Influenza Surveillance of the Last Two Seasons: 2013-2014 and 2014-2015

Flu caused by influenza viruses, is a serious public health problem all over the world with its high morbidity and mortality. Therefore World Health Organization (WHO) regularly collects the results of national influenza surveillance, evaluates the results and shares them on international portal. Thus, it provides the possibility of rapid prevention and preparation of countries that needs to be taken on the fight against the epidemic flu. Starting from 2004-2005 season until today the current flu activity in our country is also followed in accordance with sentinel surveillance. The aim of this study was to evaluate the results of sentinel surveillance data obtained by National Influenza Reference Laboratory in Istanbul University Faculty of Medicine, in 2013-2014 and 2014-2015 seasons. For this purpose, nasal/nasopharyngeal swab samples taken from the patients diagnosed as influenza-like illness by the volunteer family physicians in Izmir, Istanbul, Antalya, Edirne and Bursa were included in the study. A total of 1240 samples were delivered to our laboratory in three days, in Virocult (R) transport culture medium according to cold chain rules. All the samples were studied by real-time polymerase chain reaction (Rt-PCR) according to the protocols of Centers for Disease Control and Prevention (CDC). In our study, the positivity rates of influenza viruses in 2013-2014 and 2014-2015 seasons were detected as 31.4% (202/641) and 44.4% (289/650), respectively. In 2013-2014 season, influenza A(H3N2) virus was the predominant type with a rate of 93.1% (188/202), and the rest was influenza B virus (14/202; 6.9%). In 2014-2015 season, influenza B virus has been dominated with a rate of 60.2% (174/289), and the rates of influenza A(H1N1) pdm09 and influenza A(H3N2) were 30.4% (88/289) and 9.3% (27/289), respectively. The flu season in 2013-2014 has started at 48th week and peaked at 52nd week, while it was started later in the second week in 2014-2015 season and peaked at 10th-13th week. The lineage of the influenza B viruses isolated in both seasons were identified as B/Yamagata. Antigenic characterization of influenza A viruses isolated in our laboratory was found compatible with the vaccine strains. In conclusion, surveillance studies are highly important for the determination of the effects of flu on public health and identification of the approaches for fighting with flu. In this sense, influenza surveillance of the countries are required to implement more effectively in an expanded field of scale