Epidemiological model of hepatitis B with age structure.

Multistate epidemiological model with age structure is constructed on the grounds of natural history of the hepatitis B. Essential epidemiological classes constitute the basis of the model. Epidemiological parameters and the coefficients of transfer among the classes were determined from available information. Uncertainty of infectiousness of some classes of the population was an important constraint in model formulation. Population structure, the distribution of epidemiological classes and other parametric values were rather arbitrarily set but these can be changed as more accurate information becomes available. As new information on natural history may become available this can be incorporated into the present model, with appropriate modifications of its structure. The computer program+ of the model has been written in BASIC language, and can be accommodated within microcomputers. The model is used for simulation of endemic and epidemic situations. It is 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 cost-effectiveness analysis of various public health control programmes can also be carried out with the model. The model is evaluated through the simulations of actual and hypothetical situations. The model in its present form, permits simulation of the disease dynamics in various populations and epidemic situations. It seems to be a useful tool in the study of hepatitis B dynamics, its epidemic patterns and in the search for the effective and cost-effective, control strategies.