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AbstractMathematical models of disease transmission are being used increasingly in the design of population-based vaccination programs. Their use is illustrated in a review of some modeling studies that have implications for the use of measles, mumps, and rubella vaccine. Investigations of vaccination strategy options yield predictions for effectiveness and cost-effectiveness analyses. A quantitative understanding of the factors affecting disease transmission enables the setting of targets for vaccination programs and underpins disease elimination initiatives.

AbstractMathematical models of disease transmission are being used increasingly in the design of population-based vaccination programs. Their use is illustrated in a review of some modeling studies that have implications for the use of measles, mumps, and rubella vaccine. Investigations of vaccination strategy options yield predictions for effectiveness and cost-effectiveness analyses. A quantitative understanding of the factors affecting disease transmission enables the setting of targets for vaccination programs and underpins disease elimination initiatives.

Background The epidemiology of hepatitis A in countries across the world is changing due to improvements in hygiene and living conditions which reduce the transmissibility of the infection. Methods A mathematical model Is formulated to describe the changes in incidence of a directiy transmitted infection produced by a long term decline in its transmissibility. The basic reproduction number, the parameter describing transmissibility, is considered as a function of time. The relationship between the basic reproduction number and the force of infection is derived. Results Theoretical examples demonstrate that a decline in transmissibility results in an initial decline in the force of Infection, but that this may be followed by a substantial resurgence. Resurgences may be possible after several decades of declining incidence, and are most marked following a rapid decline. Conclusions Countries which have experienced a rapid decline in the incidence of hepatitis A may be at risk of a resurgence. More detailed mathematical models, informed with data from regular age-stratified serologlcal surveys, should provide the basis for decisions on vaccination policy.