Vaccination, evolution and changes in the efficacy of vaccines: a theoretical framework.

Abstract : The evolution of vaccine-resistant strains of infectious agents is potentially a huge problem for their control by immunization. Yet, for many infectious diseases, it has been possible to drive them to the verge of extinction without vaccine escape mutants arising. This paper establishes a theoretical framework within which to ask why this should be so, what properties of vaccines allow this situation and what might happen in situations where vaccine escape mutants do arise.