Influenza: a scientometric and density-equalizing analysis.

Background: Novel influenza in 2009 caused by H1N1, as well as the seasonal influenza, still are a challenge for the public health sectors worldwide. An increasing number of publications referring to this infectious disease make it difficult to distinguish relevant research output. The current study used scientometric indices for a detailed investigation on influenza related research activity and the method of density equalizing mapping to make the differences of the overall research worldwide obvious. The aim of the study was to compare scientific effort over the time as well as geographical distribution including the cooperation on national and international level.

Methods: Therefore, publication data was retrieved from Web of Science (WoS) of Thomson Scientific. Subsequently the data was analysed in order to show geographical distributions and the development of the research output over the time.The query retrieved 51,418 publications that are listed in WoS for the time interval from 1900 to 2009. There is a continuous increase in research output and general citation activity especially since 1990.

Results: The identified all in all 51,418 publications were published by researchers from 151 different countries. Scientists from the USA participate in more than 37 percent of all publications, followed by researchers from the UK and Germany with more than five percent. In addition, the USA is in the focus of international cooperation.In terms of number of publications on influenza, the Journal of Virology ranks first, followed by Vaccine and Virology. The highest impact factor (IF 2009) in this selection can be established for The Lancet (30.75). Robert Webster seems to be the most prolific author contributing the most publications in the field of influenza.

Conclusions: This study reveals an increasing and wide research interest in influenza. Nevertheless, citation based-declaration of scientific quality should be considered critically due to distortion by self-citation and co-authorship.