Publication trends of research on COVID-19 and host immune response: A bibliometric analysis

Abstract

Introduction: As the first bibliometric analysis of COVID-19 and immune responses, this study will provide a comprehensive overview of the latest research advances. We attempt to summarize the scientific productivity and cooperation across countries and institutions using the bibliometric methodology. Meanwhile, using clustering analysis of keywords, we revealed the evolution of research hotspots and predicted future research focuses, thereby providing valuable information for the follow-up studies.

Methods: We selected publications on COVID-19 and immune response using our pre-designed search strategy. Web of Science was applied to screen the eligible publications for subsequent bibliometric analyses. GraphPad Prism 8.0, VOSviewer, and CiteSpace were applied to analyze the research trends and compared the contributions of countries, authors, institutions, and journals to the global publications in this field.

Results: We identified 2,200 publications on COVID-19 and immune response published between December 1, 2019, and April 25, 2022, with a total of 3,154 citations. The United States (611), China (353), and Germany (209) ranked the top three in terms of the number of publications, accounting for 53.3% of the total articles. Among the top 15 institutions publishing articles in this area, four were from France, four were from the United States, and three were from China. The journal Frontiers in Immunology published the most articles (178) related to COVID-19 and immune response. Alessandro Sette (31 publications) from the United States were the most productive and influential scholar in this field, whose publications with the most citation frequency (3,633). Furthermore, the development and evaluation of vaccines might become a hotspot in relevant scope.

Conclusions: The United States makes the most indispensable contribution in this field in terms of publication numbers, total citations, and H-index. Although publications from China also take the lead regarding quality and quantity, their international cooperation and preclinical research need to be further strengthened. Regarding the citation frequency and the total number of published articles, the latest research progress might be tracked in the top-ranking journals in this field. By analyzing the chronological order of the appearance of retrieved keywords, we speculated that vaccine-related research might be the novel focus in this field.

Keywords: COVID-19; SARS-CoV-2; bibliometric analysis; immune response; sepsis.

Figure 1

Detailed flowchart of search, screening, and registration on the Web of Science.

Figure 2

Publication of articles in various countries/regions. (A) The total number of citations (×0.05) and H-index (×10) of articles from the top 15 countries ranked by publications' number. (B) Density map of the top 15 countries ranked by number of publications. (C) International cooperation among top 15 countries. (D) The top 15 countries were shown in chronological order of publications.

Figure 3

Institutions and journals publishing articles on COVID-19 and immune response. (A) Top 15 institutions with the most publications on immunization and COVID-19. (B) The ranking list of global journals publishing the most articles on immunization and COVID-19. The X-axis represented the percentage of the published number of each institution or journal to the total number of publishments. (C) The co-authorship network of top 20 institutions, and per institution had more than 20 publications with international cooperation. (D) The top 20 institutions were shown in chronological order of publications.

Figure 4

Cluster analysis diagram of research hotspots. Keywords that appeared at least 85 times in titles and abstracts were analyzed by VOSviewer software. The larger the circle of the keyword, the more frequently it appeared. The co-occurrence times of two keywords determined the distance between them. (A) The keywords were classified into three clusters: clinical research (red), acquired immunity-related research (green), and innate immunity-related research (blue). (B) Keywords were colored in chronological order. Purple keywords were the early-emerging ones, whereas keywords in yellow appeared more recently.

Figure 5

Cluster analysis plot of references for co-citation. Top 139 articles cited at least 50 times were analyzed by VOSviewer. (A) Each circle in the figure represented a reference of co-citation, and the circle size was proportional to the number of citations. All references were divided into 3 clusters according to their contents: clinical studies on COVID-19 (red), basic research on SARS-CoV-2 (blue), and the cellular and molecular basis of immune-related pathogenesis for COVID-19 disease (green). (B) The thermodynamic chart of references. All references of co-citation were colored difference according to their citations. References with the highest number of citations were marked in red.