The effect of the rapid growth of covid-19 publications on citation indicators

A concern has been raised that "covidization" of research would cause an overemphasizes on covid-19 and pandemics at the expense of other research. The rapid growth of publications related to the Covid-19 pandemic renders a vast amount of citations from this literature. This growth may affect bibliometric indicators. In this paper I explored how the growth of covid-19 publications influences bibliometric indicators commonly used in university rankings, research evaluation and research allocation, namely the field normalized citation score and the journal impact factor. I found that the burst of publications in the early stage of the covid-19 pandemic affects field-normalized citation scores and will affect the journal impact factor. Publications unrelated to covid-19 are also heavily affected. I conclude that there is a considerable risk to draw misleading conclusions from citation indicators spanning over the beginning of the covid-19 pandemic, in particular when time series are used and when the biomedical literature is assessed.