1,721,013 research outputs found
Comparison of hemagglutination inhibition, single radial hemolysis, virus neutralization assays, and ELISA to detect antibody levels against seasonal influenza viruses
Full text linkBackground: The immunological response to influenza vaccine and/or natural infection is evaluated by serological techniques, the most common being hemagglutination inhibition (HI), single radial hemolysis (SRH), and virus neutralization assays, which is commonly used in a micro-neutralization (MN) format. ELISA is not officially required; however, this assay is able to measure different class-specific antibodies. The four assays identify different sets or subsets of antibodies. Objectives: The aim of this study was to establish the correlation among four serological assays using four seasonal influenza strains. Methods: The HI, SRH, MN assays, and ELISA were performed on four seasonal influenza strains. Results: A strong positive correlation was found between HI and MN and between SRH and MN assays for influenza A strains. The B strains also showed good correlations among the three assays. A positive correlation was also found between ELISA and the “classical” assays for all strains. Concerning the correlates of protection, as defined by HI ≥ 40 and SRH ≥ 25 mm2, good agreement was observed for the influenza A strains. By contrast, the agreement for the B strains was very low. Conclusions: There is a positive strong correlation among the four serological assays for both A and B strains, especially for the HI and MN assays. There is good agreement on correlates of protection between HI and SRH assays for the A strains, but very low agreement for the B strains, suggesting higher sensitivity of SRH than HI assay in detecting antibodies against the influenza B viruses
Immunity to measles in Italian children and adolescents: a persistent problem in view of measles elimination
No full textBACKGROUND: Despite efforts to increase coverage by two doses of measles vaccine in Italy, measles continues to circulate, with over 13 000 cases of disease since 2013. This study aimed to evaluate immunity to measles in Italian children and adolescents.METHODS: A total of 378 serum samples from subjects aged 9months-18years were collected in Northern, Central and Southern regions of Italy between 2012 and 2016. Specific IgG antibodies against measles were measured by a commercial ELISA kit.RESULTS: The frequency of IgG-positive samples ranged from 10.5% in infants under 1year to 98.3% in children aged 6-7years. The frequency of IgG was 72.2% in subjects aged 1-2years, 85.6% in those aged 3-5years and 88.3 and 86.8% in those aged 8-10 and 11-18years, respectively. In Northern Italy, IgG prevalence was consistent with data on vaccination coverage, whereas some differences were observed in samples from subjects aged more than 8years in Central and Southern Italy.CONCLUSIONS: Our findings confirm that a large proportion of children and adolescents in Italy are still susceptible to measles. While data on first- and second-dose measles vaccination are essential, they are not sufficient to identify susceptible population cohorts to be targeted by vaccination
Measles immunity over two decades in two large Italian Regions: How far is the elimination goal?
No full textIn Italy, the inclusion of measles vaccine in children immunization schedule and the promotion of national mass vaccination campaigns increased measles vaccination coverage. However, measles outbreaks continue to occur increasingly involving adolescents and adults. The aim of this study was to evaluate the prevalence to measles antibody in a sample of Italian population between 1993 and 2018. Human serum samples from subjects aged 3-40 years were collected between 1993 and 2018 and tested for measles IgG antibodies by commercial ELISA. During the study period, the 3-10-year-old age group showed the most important change, with a significant increase in 2003-2007 in both seroprevalence and IgG levels, followed by a slow decrease. The 11-18-year-old age group showed relatively stable seroprevalence rates and IgG levels over the years. The 19-30-year-old group showed stable seroprevalence rates, albeit with a decrease in IgG levels. After a significant increase in 1999-2002, the 31-40-year-old age group had high seroprevalence rates and IgG levels. Despite efforts at national level for implementing measles vaccination, a large proportion of the population is still susceptible to measles. Even if vaccination coverage increases enough to achieve the level of immunization required for herd immunity in new birth cohorts, outbreaks will continue to occur if there are immunity gaps in older age groups. Establishing policies for measles vaccination targeting adult population is needed to close immunity gaps and reach the elimination goal. (c) 2021 Elsevier Ltd. All rights reserved
Influenza Virus Vaccine
No full textThe present invention relates to vaccine compositions comprising at least three variants of a subtype of an influenza A and/or B virus antigen, wherein the at least three variants are selected on the basis of differences between their amino acid sequences. The present invention further relates to said vaccine compositions for use in a method of generating an immune response against influenza viruses. Further provided is a method for producing said vaccine compositions
Influenza Virus Vaccine
No full textThe present invention relates to vaccine compositions comprising at least three variants of a subtype of an influenza A and/or B virus antigen, wherein the at least three variants are selected on the basis of differences between their amino acid sequences. The present invention further relates to said vaccine compositions for use in a method of generating an immune response against influenza viruses. Further provided is a method for producing said vaccine compositions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Characterization of antibody response in asymptomatic and symptomatic SARS-CoV-2 infection.
Full text linkSARS-CoV-2 pandemic is causing high morbidity and mortality burden worldwide with unprecedented strain on health care systems. To investigate the time course of the antibody response in relation to the outcome we performed a study in hospitalized COVID-19 patients. As comparison we also investigated the time course of the antibody response in SARS-CoV-2 asymptomatic subjects. Study results show that patients produce a strong antibody response to SARS-CoV-2 with high correlation between different viral antigens (spike protein and nucleoprotein) and among antibody classes (IgA, IgG, and IgM and neutralizing antibodies). The antibody peak is reached by 3 weeks from hospital admission followed by a sharp decrease. No difference was observed in any parameter of the antibody classes, including neutralizing antibodies, between subjects who recovered or with fatal outcome. Only few asymptomatic subjects developed antibodies at detectable levels
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