Research intensity for neglected tropical diseases and other infectious diseases before and after the COVID-19 pandemic.

BACKGROUND: Infectious diseases can cause tremendous health and economic damage, as shown by past pandemics. Although research tends to spotlight emerging infectious diseases, neglected tropical diseases (NTDs) require sustained research and development to advance global public health. However, there is concern that the recent COVID-19 pandemic may have interrupted research on NTDs, leading to further neglect of these diseases. RESULTS: We assessed the bias of research intensities for 67 infectious diseases, including 18 NTDs, from 2016 to 2023. We calculated the burden-adjusted research intensity (BARI) index for each disease, based on disease burden and scholarly publications. Significantly high research intensity was observed for COVID-19, HIV, influenza, and Zika, while paratyphoid fever showed significantly low BARI. We found no significant difference in the median BARI index between NTDs and non-NTDs during the pandemic period of 2020-2023. Among the lowest quartile of BARI index scores, seven were still NTDs. The BARI index for cysticercosis, dengue, and schistosomiasis has declined significantly when comparing the pre- and post-pandemic periods. As for non-NTDs, the BARI of 12 diseases decreased; there was no significant difference in the proportion of diseases for which the BARI decreased during the COVID-19 pandemic between NTDs and non-NTDs. Disease characteristics and research locations were modestly associated with research intensity, and the impact of COVID-19 was not evident even in the subgroups. CONCLUSIONS: We found no evidence that NTDs, as a formal disease category, were disproportionately deprioritised in research during the COVID-19 pandemic. However, several diseases, including both NTDs and non-NTDs, showed persistently low or declining relative research intensity. As research on non-pandemic infectious diseases, including NTDs, should be viewed not as competing with pandemic preparedness and response, but as integral to it, this study emphasises the importance of sustained, wide-reaching research investments for global equity.