Funding and geographical distribution of clinical trials in infectious diseases.

Objectives: To map funding flows in infectious disease randomized clinical trials (RCTs) by examining relationships between funding sources and trial locations in high impact journals.

Methods: We conducted a secondary analysis of a previously published systematic review of 1,343 infectious disease RCTs published (2014-2023) in ten selected high-impact English language general medicine and infectious disease journals. Funding source, study site, and disease focus were extracted using a standardized data extraction form, and analysed by country income level using World Bank classifications Geographical distributions of funding and study sites were visualized using global heat maps. Funding flows between country income groups were visualized using a Sankey plot.

Results: Of the 1343 trials, 1326 disclosed funding source (98.7%). Most trials identified in this review were investigator-initiated (772/1326, 58.2%), with the U.S. government as the largest contributing funder (366/1326, 27.6%), with the National Institutes of Health specifically involved in funding 258/1326 (19.5%) of trials. When disaggregated, there was a total of 1808 unique funders. These overwhelmingly originated from high-income countries (1496/1808, 82.7%) compared to upper-middle income (130/1808, 7.2%), low-middle income (35/1808, 1.9%), and low-income (8/1808, 0.4%) countries. In contrast, the 4606 disaggregated locations of study by country, were more distributed across income levels: high-income (2521/4606 61.9%), upper-middle income (918/4606, 22.5%), lower-middle income (360/4606, 8,8%), low-income (253/4606, 6.2%). Disease focus varied geographically; trials focusing on critical care, bacterial infections, sexually transmitted infections, hepatitis, influenza, and COVID-19 were underrepresented in low-income settings.

Conclusion: Our study reveals skewed geographical and funding distributions in the global landscape of infectious disease RCTs published in these 10 selected English language high-impact journals. As key funders reduce funding internationally, the impact on the research landscape may disproportionately affect lower-middle income countries. Further efforts should be made to build sustainable funding models and research capacity in lower-middle income countries.