The concept of superspreaders, individuals who transmit infections to an unusually large number of people, has gained prominence during the COVID-19 pandemic. However, this phenomenon is not unique to COVID-19; it is a critical aspect of tuberculosis (TB) epidemiology as well.
TB, caused by Mycobacterium tuberculosis, presents an interesting case study in infectious disease transmission. While most individuals with TB cause few or no secondary infections, a small proportion of highly infectious individuals can significantly impact future transmission. This variability in transmission potential highlights the need for innovative strategies to combat TB superspreaders.
In a recent perspective piece, researchers from Boston University and the University of Colorado delve into the historical and contemporary evidence surrounding M. tuberculosis superspreading. They argue that this phenomenon represents both a challenge and an opportunity for global TB control efforts.
The researchers introduce the concept of "superspreading niches" - specific parts of community contact networks where highly infectious individuals intersect with highly susceptible contacts. By identifying the characteristics of these niches, they believe novel interventions can be designed to disrupt transmission early on.
"We propose that understanding superspreading niches could lead to targeted interventions that prevent highly infectious source cases from transmitting the disease to their susceptible contacts," explains Karen Jacobson, the study's senior author and an associate professor at Boston University School of Medicine.
Superspreading is a complex and poorly understood phenomenon, with multiple factors contributing to its occurrence. According to Jacobson, our current understanding of these factors is vague and insufficient for improving public health actions. However, mathematical modeling studies suggest that preventing superspreading can have a significant impact on infectious disease epidemics, including TB.
"TB may be uniquely well-suited to superspreading-focused prevention strategies," Jacobson adds. Unlike respiratory viruses, TB is a slowly progressive disease, providing a larger window of opportunity for deploying transmission-interrupting interventions. Additionally, individuals receiving effective antibiotic therapy for TB become non-infectious within days, offering a rapid way to curb transmission. Preventive therapy for exposed individuals who have not yet developed the disease is also highly effective, further supporting the potential for disrupting TB superspreading.
As we continue the global fight against TB, understanding and exploiting superspreading could be a powerful tool in our arsenal. By targeting these high-impact individuals and their specific transmission niches, we may be able to make significant strides in controlling this ancient disease.
