Epidemiology of prenatal infections: an extension of the congenital rubella model.

The properties of prenatal infections are studied through the development of a theoretical model. The responses of such epidemic systems to natural changes in transmission rates, age at maternity, social stratification, geographical heterogeneity, epidemic instability and the introduction of vaccination, are examined. The effects of age-at-vaccination, efficacy of vaccination, wild virus interaction, and vaccine-immunity decay rates, are also examined in some detail. Several powerful putative influences upon the evolution of prenatally determined infective diseases are identified. They provide scientific tools for detecting processes of this kind.