Research Output and Global Trends in Lassa Fever: A 50-Year Bibliometric Analysis (1975-2025)

Lassa fever poses a significant public health threat, primarily concentrated in West Africa. This bibliometric study aimed to document research outputs concerning Lassa fever. It analyzes trends in research publication output, the participation of various countries, productive institutions and their collaboration networks, influential funding agencies, predominant research fields, top-tier journals, prolific authors, and keyword frequencies.

Lassa fever-related publications published between 1975 and 2025 were retrieved from the Scopus and Web of Science (WoS) databases by using the keywords "Lassa fever," OR "Lassa virus," OR "Lassa hemorrhagic fever," OR "Lassa mammarenavirus," OR "LASV." The retrieved records were restricted to the study period, screened for English language, and further refined to include original research articles. The Scopus and WoS datasets were analyzed independently using Biblioshiny (Bibliometrix package in RStudio Cloud) to evaluate research productivity and trends, including contributions by authors, countries, institutions, and journals, whereas VOSviewer (Van Eck & Waltman, Leiden University, Netherlands) was used for network visualization, construct collaboration, and keyword co-occurrence networks. Country productivity was assessed using the full-counting approach based on authors' institutional affiliations.

Following the application of the eligibility criteria, 1776 and 2451 English-language original research articles on Lassa fever from Scopus and WoS databases, respectively, were included in the bibliometric analysis. The findings demonstrated an overall increase in research output during the study period (1975-2025), with publication output peaking in 2024. The United States and Nigeria were the leading contributors to Lassa fever research in both databases. Despite the endemicity of Lassa fever in West Africa, only a few number of other African countries were represented among the top 20 global research contributors. Bernhard-Nocht-Institut für Tropenmedizin and the Centers for Disease Control and Prevention were the most prolific institutions in both databases. The National Institute of Allergy and Infectious Diseases (Scopus) and the US Department of Health and Human Services (WoS) emerged as the leading funding agencies. "Medicine" (Scopus) and "Infectious Diseases" (WoS) were the predominant research fields. The most prolific authors included Günther S., De La Torre J.C., and Garry R.F., whereas the Journal of Virology was the leading publication source in both databases. Keyword analysis identified "Lassa fever" and "Lassa virus" as the most frequent occurring terms.

The bibliometric analysis provides an updated, comprehensive historical perspective of progress in Lassa fever research. It also highlighted the pivotal role of diverse stakeholders. However, African research output is disproportionately low in relation to that of other countries, implying a need for increased funding and focus on Lassa fever research for effective prevention and control.