Strategy for rubella vaccination.

Two separate models are developed for predicting the effectiveness of alternative Rubella vaccination policies. A simple mathematical steady-state model is used to predict long-term consequences and a more complex dynamic computer-simulation model is used in order to predict shorter-term results. The dynamic model takes account of population heterogeneities of the transmission rate, as well as secular changes, together with varying levels of efficacy/uptake, different possibilities of vaccine-immunity decay, and interactions with wild-virus. It is concluded that under optimal conditions of uptake and efficacy the vaccination of pre-school boys and girls will give better results than the vaccination of 14 year old girls alone, but that where conditions are less than optimal the second policy is preferable. For the first policy, low uptake or low efficacy or moderate levels of decaying vaccine-immunity can result in severe rebounds in the incidence of CRS and the medium-term results can be worse than if no vaccination had been provided. If firm reassurance can be obtained regarding the relative permanence of vaccine-immunity, then combined vaccination programmes will give satisfactory safeguards against the risks of low uptake.