A nested model for pneumococcal population dynamics
Streptococcus pneumoniae is a pathogen of major public health concern globally. Pneumococcal strains exhibit diversity in their capsular serotype, metabolic profiles, and properties of antibiotic resistance (among other traits). Pneumococcal conjugate vaccines have been successful at targeting a subset of the circulating serotypes. Following such perturbation, pneumococcal populations have been shown to undergo significant shifts, indicative of competition both between and within serotypes. Using a nested model with explicit within-host dynamics, we show how competition between these types, along with heterogeneity in duration of carriage, may help explain patterns of vaccine-induced population dynamics.