Analysis of research intensity on infectious disease by disease burden reveals which infectious diseases are neglected by researchers

Abstract

Infectious diseases are associated with considerable morbidity and mortality worldwide. Although human, financial, substantial, and time resources are limited, it is unknown whether such resources are used effectively in research to manage diseases. The correlation between the disability-adjusted life years to represent disease burden and number of publications as a surrogate for research activity was investigated to measure burden-adjusted research intensity for 52 infectious diseases at global and country levels. There was significantly low research intensity for paratyphoid fever and high intensity for influenza, HIV/acquired immunodeficiency syndrome, hepatitis C, and tuberculosis considering their disease burden. We identified the infectious diseases that have received the most attention from researchers and those that have been relatively disregarded. Interestingly, not all so-called neglected tropical diseases were subject to low burden-adjusted research intensity. Analysis of the intensity of infectious disease research at a country level revealed characteristic patterns. These findings provided a basis for further discussion of the more appropriate allocation of resources for research into infectious diseases.

Keywords: epidemiology; infectious diseases; neglected tropical diseases; philology; public health.

Fig. 1.

Association between disease burden and research intensity. Double logarithmic plot of disease burden (in DALYs) against research intensity (number of publications) for 52 infectious diseases at a global level in 2010–2017. The regression line and its 95% prediction interval were drawn. Diseases considered as outliers and excluded to draw the regression line are indicated by open circles (see Materials and Methods for detail).

Fig. 2.

Indices of BARI for the 52 infectious diseases in the 1990s, 2000s, and 2010s, calculated for each year and averaged by decade. The diseases are ordered according to the index in the 2010s. Error bars show SD of the indices of each year. Black dots indicate neglected tropical diseases, and slanted arrows indicate diseases with significant change in the BARI over the three decades.

Fig. 3.

Analysis of the BARI index of infectious diseases at global and country levels. (A) BARI index by disease classification at a global level. The median for each group is shown by a horizontal line. The disease burden in DALYs was grouped by tertile. Difference in indices between and among categories was tested by the Kruskal–Wallis Test. n.s., not significant. (B) The index for representative diseases at a country level by region and economic level. When there are one or more publications about a disease that has no DALYs there, dots were plotted on the top horizontal broken line. When there is no publication about a disease that has no DALYs there, dots were plotted on the middle horizontal broken line. When there is no publication about a disease that has DALYs there, dots were plotted on the bottom horizontal broken line. Results for all 52 diseases can be found in SI Appendix, Fig. S2.