ECONOMIC-EVALUATION OF VACCINATION

With increasing expenditures in healthcare, in absolute terms as well as in relative terms, interest in the efficiency of certain interventi ons in healthcare has also increased. Faced with the limitations of th e healthcare budget, budget holders try to find the optimal way of div iding their funds over different healthcare provisions, without discar ding human and medical considerations. In economic terms, this process could be called the 'optimal allocation of scarce resources over the inputs of a function of production'. The means of production would the n be 'the provision of healthcare', whereas the output would be 'impro vement of health'. Clearly, choices have to be made with regard to spe nding the healthcare budget. One of the instruments that can help in m aking such choices is the economic evaluation. In economic evaluations of vaccinations, different vaccination strategies are defined. The co nsequences in terms of costs and effects of each strategy are being ca lculated and compared with a reference strategy, which is often the no nintervention strategy, i.e. 'no vaccination'. According to the way in which the benefit or the output of vaccination - 'improvement of heal th' - is measured, a distinction is made between various methods of ec onomic evaluation: in a cost-effectiveness analysis, health gains are measured in natural units (e.g. prevented infections, prevented illnes s days, life-years gained, etc.); in a cost-utility analysis, the qual ity of the health gains is taken into account (e.g. quality-adjusted l ife-year); and in a cost-benefit analysis, health gains are converted into monetary units. Costs can be divided into direct and indirect cos ts. Direct costs are directly related to medical treatments (medicatio n, laboratory tests, consultations, etc.) or to vaccination (e.g. purc hasing price of the vaccine, costs for administering the vaccine, trea tment of side effects, etc.). Costs indirectly related to treatments a nd vaccination are mainly costs of lost productivity due to disease mo rbidity or mortality, and opportunity costs. In comparison with other vaccine-preventable infections, influenza vaccination for the elderly seems acceptable from an economic point of view (about $US650 per life -year gained, in 1981). Cost-effectiveness ratios of other vaccination s range from about $US720 per life-year gained for universal hepatitis B vaccination to about $US190 000 per life-year gained for universal Haemophilus influenzae type b vaccination. Because of differences in m ethods, the representation of results, and country-specific parameters , different economic evaluations of the same vaccination strategy may show divergent results. Therefore, until sufficient standardisation of economic evaluations exists, comparisons of the sort we are making he re should be interpreted with prudence.