1,720,959 research outputs found
Defining the Recipe for an Optimal Rotavirus Vaccine Introduction in a High-Income Country in Europe
No full textObservational data over 15 years of rotavirus vaccine introduction in Belgium have indicated that rotavirus hospitalisations in children aged <5 years plateaued at a higher level than expected, and was followed by biennial disease peaks. The research objective was to identify factors influencing these real-world vaccine impact data. We constructed mathematical models simulating rotavirus-related hospitalisations by age group and year for those children. Two periods were defined using different model constructs. First, the vaccine uptake period encompassed the years required to cover the whole at-risk population. Second, the post-uptake period covered the years in which a new infection/disease equilibrium was reached. The models were fitted to the observational data using optimisation programmes with regression and differential equations. Modifying parameter values identified factors affecting the pattern of hospitalisations. Results indicated that starting vaccination well before the peak disease season in the first year and rapidly achieving high coverage was critical in maximising early herd effect and minimising secondary sources of infection. This, in turn, would maximise the reduction in hospitalisations and minimise the size and frequency of subsequent disease peaks. The analysis and results identified key elements to consider for countries initiating an optimal rotavirus vaccine launch programme
Human rotavirus vaccine (Rotarix): Focus on effectiveness and impact 6 years after first introduction in Africa
Full text linkArtículo de publicación ISIA decade after licensure of the human rotavirus vaccine (HRV), a wealth of evidence supports a reduction of rotavirus (RV) gastroenteritis-associated mortality and hospitalizations following HRV inclusion in national immunization programs. Nevertheless, the majority of real-world data has been generated in high-or middle-income settings. Clinical efficacy trials previously indicated RV vaccine performance may be lower in less-developed countries compared with wealthier counterparts. Using recently published data from Africa, we examine the effectiveness and impact of HRV in resource-deprived areas, exploring whether vaccine performance differs by socioeconomic setting and the potential underlying factors. HRV vaccine effectiveness in early adopting African countries has proven to be similar or even superior to the efficacy results observed in pre-licensure studies
Explaining the formation of a plateau in rotavirus vaccine impact on rotavirus hospitalisations in Belgium
No full textBackground: Observational data on the reduction in hospitalisations after rotavirus vaccine introduction in Belgium suggest that vaccine impact plateaued at an unexpectedly high residual hospitalisation rate. The objective of this analysis was to identify factors that influence real-world vaccine impact. Methods: Data were collected on hospitalisations in children aged < 5 years with rotavirus disease from 11 hospitals since 2005 (the RotaBIS study). The universal rotavirus vaccination campaign started late in 2006. A mathematical model simulated rotavirus hospitalisations in different age groups using vaccine efficacy and herd effect, influenced by vaccine coverage, vaccine waning, and secondary infection sources. The model used optimisation analysis to fit the simulated curve to the observed data, applying Solver add-in software. It also simulated an 'ideal' vaccine introduction maximising hospitalisation reduction (maximum coverage, maximum herd effect, no waning), and compared this with the best-fit simulated curve. Modifying model input values identified factors with the largest impact on hospitalisations. Results: Compared with the 'ideal' simulation, observed data showed a slower decline in hospitalisations and levelled off after three years at a higher residual hospitalisation rate. The slower initial decline was explained by the herd effect in unvaccinated children. The higher residual hospitalisation rate was explained by starting the vaccine programme in November, near the rotavirus seasonal peak. This resulted in low accumulated vaccine coverage during the first rotavirus disease peak season, with the consequential appearance of secondary infection sources. This in turn reduced the herd effect, resulting in a diminished net impact. Conclusions: Our results indicate that countries wishing to maximise the impact of rotavirus vaccination should start vaccinating well ahead of the rotavirus seasonal disease peak. This maximises herd effect during the first year leading to rapid and high reduction in hospitalisations. Secondary infection sources explain the observed data in Belgium better than vaccine waning. (c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).BS was an employee of GSK until retirement in September 2020. The current research was conducted after he left GSK. He recently joined the Faculty of Medicine and Life Sciences, Research Group Care and Ethics, at the University of Hasselt, Hasselt, Belgium, as guest professor. DS is a consultant and has not been paid for her contribution to this work. MR is a paediatric professor and clinician. He has not been paid for his contribution to this work. BB is an employee of GSK and holds shares of the GSK group of companies.
The authors would like to thank Carole Nadin (Fleetwith Ltd, on behalf of HEBO) for editorial assistance
Lessons Learned from Long-Term Assessment of Rotavirus Vaccination in a High-Income Country: The Case of the Rotavirus Vaccine Belgium Impact Study (RotaBIS)
No full textAbstract Introduction The rotavirus (RV) vaccine Belgium Impact Study (RotaBIS) evaluated the vaccine effect on RV-related hospital care in children up to 5 years old over a period of 13 years. Different forces were identified that influence the reduction in hospital care. Our analysis aims to report on the current RotaBIS dataset and explore through model simulation whether, how, and when the results could have been improved. Methods As performed in previous assessments, this analysis evaluated RV-related events per year, per age group, RV nosocomial infections, hospitalization duration, and herd effect. It subsequently identified results that were surprising or unexpected. To know whether those data could have been improved through specific interventions, we developed a model with the forces acting on the disease transmission and the vaccine effect on RV-related hospital care. Scenario analysis of the forces should explain the current findings and identify ways to optimize the results. Results The RotaBIS data show that annual RV-related hospital cases (n = 1345 pre-vaccination) dropped by 70% (95% confidence interval [CI] 66–74%) by year 5 (n = 395) after vaccine introduction, and by 84% (95% CI 79–89%) by year 10 (n = 217). The herd effect during the first year was limited to 14% extra gain. During the last 5 years, small disease increases were seen biennially. The simulation model indicates that higher vaccine coverage of the major transmitters during the peak season of the first year of vaccination could have reduced RV-related hospital care by nearly 90% at 5 and 10 years after vaccine introduction owing to a higher herd effect. The smaller peaks observed in recent years would have been dramatically reduced. Conclusion The current RotaBIS data show a maintained reduction, around 76%, in RV hospitalization cases. Simulations show that these results could have been improved to an important extent with a more optimal initiation of the vaccination program. Trial registration ClinicalTrials.gov identifier, NCT01563146 and NCT01563159
Measuring the Vaccine Success Index: A Framework for Long-Term Economic Evaluation and Monitoring in the Case of Rotavirus Vaccination
No full textNew vaccination programs measure economic success through cost-effectiveness analysis (CEA) based on an outcome evaluated over a certain time frame. The reimbursement price of the newly approved vaccine is then often reliant on a simulated ideal effect projection because of limited long-term data availability. This optimal cost-effectiveness result is later rarely adjusted to the observed effect measurements, barring instances of market competition-induced price erosion through the tender process. However, comprehensive and systematic monitoring of the vaccine effect (VE) for the evaluation of the real long-term economic success of vaccination is critical. It informs expectations about vaccine performance with success timelines for the investment. Here, an example is provided by a 15-year assessment of the rotavirus vaccination program in Belgium (RotaBIS study spanning 2005 to 2019 across 11 hospitals). The vaccination program started in late 2006 and yielded sub-optimal outcomes. Long-term VE surveillance data provided insights into the infection dynamics, disease progression, and vaccine performance. The presented analysis introduces novel conceptual frameworks and methodologies about the long-term economic success of vaccination programs. The CEA evaluates the initial target vaccination population, considering vaccine effectiveness compared with a historical unvaccinated group. Cost-impact analysis (CIA) covers a longer period and considers the whole vaccinated and unvaccinated population in which the vaccine has direct and indirect effects. The economic success index ratio of CIA over CEA outcomes evaluates long-term vaccination performance. Good performance is close to the optimal result, with an index value <= 1, combined with a low CEA. This measurement is a valuable aid for new vaccine introductions. It supports the establishment of robust monitoring protocols over time.The authors would like to thank Carole Nadin for editorial assistance
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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