Preprints vs. Journal Articles: Citation Impact in COVID-19 Research

Focusing on article and citation count, this study examined 110 academic journals whose papers on COVID-19 were indexed in PubMed from 2020 to 2023. To analyze these journals’ characteristics, this study introduced the concepts of paper ratio, citation ratio, and citation impact. Journals with similar trends in paper and citation count were positioned near the diagonal on a two-dimensional graph (y=x) with paper ratio on the x-axis and citation ratio on the y-axis, indicating a slope close to 1. Conversely, the greater the disparity between paper ratio and citation ratio, the wider the angle between the journal’s position and the diagonal. Of the 110 journals in 2020, 83 were above the diagonal with a citation impact greater than 1, while 27 were below the diagonal with a citation impact of 1 or lower. Notably, nine journals—BMC Health Services Research, Genome Medicine, Nature, Annals of Epidemiology, BMC Bioinformatics, Nature Microbiology, PLoS Computational Biology, Medicine (Baltimore), andJournal of Clinical Investigation—showed high citation impact, with preprint-distributed papers being cited nearly five times more than directly submitted papers. This study demonstrates that articles initially distributed as preprints in these journals tend to receive substantially more citations than directly submitted ones.