Epidemiological model of hepatitis B

This is a preliminary report on a multistate epidemiological model without age structure constructed on the grounds of the natural history of hepatitis B. In determining twelve essential epidemiological classes and related epidemiological parameters the lack of precise definitions of certain classes and their infectiousness was an important constraint in model formulation. For this reason the distribution of some classes and their parametric values were rather arbitrarily set. As more exact information on natural history becomes available it can be directly incorporated into the present model. The computer programme of the model has been written in basic language. The model was used for the simulation of endemic and epidemic situations. It was applied for simulating the natural course of infection as well as the effects of various public health interventions, such as passive and active immunization and/or application of appropriate sanitary and hygienic measures. The model is evaluated through the above simulations of actual and hypothetical situations. The cost-effectiveness analysis of various public health interventions can also be carried out with the model. The model in its present form, in spite of some uncertainties as far as epidemiological parameters are concerned, seems to be useful in the study of hepatitis B dynamics and its epidemiological patterns and in the search for effective and cost-effective control strategies. The model needs further refinement.