Unravelling the within-host dynamics of Group A Streptococcus from population-level observations of prevalence and strain diversity (MCB)
Group A Streptococcus (GAS) is a ubiquitous human pathogen with high strain diversity, and a major cause of death and disability globally. The development of an effective vaccine against GAS is currently hampered by our incomplete understanding of GAS infection and immunity. Epidemiological studies indicate a positive association between the prevalence of GAS disease in different host populations and the diversity of concurrently circulating strains. In this seminar, I will describe how we translated these epidemiological observations into new understanding of GAS infection and immunity through the development and analysis of a novel agent-based mathematical model of GAS transmission. Our results support the hypothesis that the clearance of GAS infection likely confers temporary strain-specific immunity, with reduced or absent cross protection against infection by other strains. Furthermore, our results suggest that the success of GAS vaccines will depend on their ability to elicit either long-lasting strain-specific immunity or strong cross-immunity over multiple strain types.
Dr Rebecca Chisholm, University of Melbourne