Content analysis and level of evidence of the most cited scientific articles on Covid-19 on the Web of Science

The scientific literature on Covid-10 has seen unprecedented growth, being published so rapidly as to question its quality and the peer review process. This research analyzes the characteristics of the publications on Covid-19 with the greatest impact, mainly considering their content and the quality and level of evidence of the studies. The Web of Science Core Collection was searched for articles containing the terms "Covid-19" and "SARS-CoV-2," and the 100 most cited articles published in 2020 were selected. The data extracted included bibliographic data, journal submission, acceptance, and publication dates, the main topics covered, the type of study, and the level of evidence according to the SIGN scale, as well as the existence of corrections. Half of the articles were published in three journals, most of them in the early months of 2020. The most frequent types of studies were case series, narrative reviews, and expert opinions, with only one randomized controlled clinical trial. The articles focused mainly on the clinical characteristics and complications of patients, diagnostic and treatment methods, as well as the epidemiology and characteristics of the virus. The design of these studies reflects a low level of evidence, and data and scientific quality may be affected by how quickly they are published and the peer review process is performed.