Abstract

The recent introduction of rotavirus vaccines into the national immunization schedules of the United States and other countries has led to substantial reductions in the incidence of severe diarrhea in children. However, there is concern over whether indirect protection evident in the short term will extend to the long term, and whether the selective pressures imposed by vaccines will lead to the emergence of non-vaccine-type strains. Furthermore, vaccine efficacy was found to be considerably lower in developing countries where the burden of rotavirus mortality is greatest. Using data-driven models for the transmission dynamics of rotavirus, we generate predictions about indirect protection by relating individual-level protection offered by vaccines to population-level effects. We compare a variety of model structures to examine the sensitivity of predictions to assumptions about the basic epidemiology of disease. Incorporating the interaction of the five common rotavirus genotypes into a model offers insight into patterns of coexistence and genotype cycling apparent pre-vaccination, and we hypothesize how existing vaccines may impact the distribution of prevailing genotypes. Finally, we use models to explore possible explanations for observed differences in vaccine efficacy between developed and developing countries.