1,721,042 research outputs found
Hepatitis B in Italy: where we are ten years after the introduction of mass vaccination
No full textIn Italy, a program of vaccination against hepatitis B targeted at the immunisation of persons at high risk began in 1983. In 1991, vaccination became mandatory for all newborns and adolescents. Since then, the vaccine has been given to more than 10 million children, with an outstanding record of safety and efficacy. The coverage rate is globally around 94%, with differences between the Northern and Southern regions, with the latter having the lower acceptance rate. According to the National Surveillance System (SEIEVA), the incidence of acute hepatitis B per 10(5) inhabitants declined from 5.4 in 1990 to 2 in 2000. The reduction was even greater among 15-24-year-old individuals, where the incidence rate per 10(5) decreased from 17.3 to 2 in the same period. In parallel with the decline of hepatitis B, hepatitis delta has also declined significantly. Catch-up immunisation of unvaccinated adolescents, as well as an effort to improve the vaccination coverage rate in high-risk groups, are required to ameliorate the efficacy of the vaccination campaign. Routine administration of booster doses of vaccine is not considered necessary to sustain immunity in immunocompetent persons. Copyright 2002 Wiley-Liss, Inc
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
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