From an economic perspective, a useful way of setting priorities for prevention is to consider the public health significance of particular conditions, the preventability of these conditions, and the efficiency of specific initiatives aimed at realising the potential for prevention.

This discussion paper addresses the first of these steps for tuberculosis (TB) and syphilis. It provides prevalence-based estimates of the costs to the health care delivery system of TB and syphilis in the year 1989-90. Preliminary estimates for the indirect impact on production in the broader economy are also provided.

Total costs for TB were estimated to be $12.0 million in 1989-90, comprised of $8.4 million for the direct cost of treatment, $2.5 million in morbidity costs (measured as the value of foregone earnings), and $1.1million in mortality costs (measured as the value of foregone earnings for nine premature deaths).

Total costs for syphilis were estimated to be $1.5 million, including $1.2 million for the direct cost of treatment, $0.2 million for morbidity costs, and $0.1 million in mortality costs from one premature death in 1989-90.

Trends in the United States indicate an increase in the incidence of TB, due to the inadequacy of health services, AIDS, and multi-drug resistant TB. An ageing population and changes in ethnicity may also be contributory factors.

The possibility that the incidence of tuberculosis in Australia could similarly increase in the future, stresses the need for Australian diagnostic and treatment programs for this disease to be maintained and improved where necessary. The cost-effectiveness of using isoniazid prophylaxis for patients with a positive Mantoux skin test should be carefully considered.

Congenital syphilis is a preventable, serious disease which can lead to the neonatal death or substantial long-term institutionalisation of children. Further analysis seems desirable in Australia to determine the adequacy of current screening programs in terms of the population they serve.

The scope and limitations of this study should be borne in mind when using the cost-of­ illness (COl) estimates. In particular, while COI studies have various useful applications, they do not provide sufficient information on their own to determine whether the resource allocation is efficient. It is also important to consider quality of life factors, despite the greater challenge posed by their measurement.

The Disease Costs and Impacts Study (DCIS) series is part of an ongoing collaborative research program with the National Centre for Health Program Evaluation, in which the methods and data sets are constantly being reviewed, revised and updated. While soundly based, COI estimates released at this point of the research program should be regarded as work-in-progress estimates.