The costs and effectiveness of surveillance of communicable disease: a case study of HIV and AIDS in England and Wales.

BACKGROUND In England and Wales, surveillance of communicable disease is carried out and co-ordinated by the Public Health Laboratory Service (PHLS). The surveillance of HIV infection and AIDS is undertaken by the PHLS AIDS Centre at the Communicable Disease Surveillance Centre (CDSC). Epidemiological data derived from surveillance are not, however, a free good: they are a resource with an associated opportunity cost and should therefore be open to economic appraisal alongside other users of health care resources such as medical interventions. This paper assembles information on the current surveillance of HIV and AIDS in England and Wales, and explores methods for performing an economic evaluation of such activities. METHODS An examination of the cost and effectiveness of the PHLS AIDS Centre's epidemiological surveillance mechanisms for HIV and AIDS in England and Wales was undertaken. The total costs of each component of surveillance of HIV and AIDS in England and Wales were calculated. Two categories of cost were estimated: peripheral costs incurred by reporters in reporting AIDS cases or HIV infections or by laboratories in collecting samples; and central costs incurred by the PHLS AIDS Centre in processing and analysing incoming data. Using these cost data and information from a cost-effectiveness register, the additional health gains that would have to be obtained from surveillance to make the programme broadly cost-effective in comparison with other accepted uses of health service resources were then estimated. RESULTS In the financial year 1993-1994 the total costs of surveillance were estimated to be 1.4 million pounds. To avoid being considered relatively cost-ineffective at least 3.5 infections per annum need to be averted. To be considered favourably cost-effective, approximately 9.5 infections per annum need to be averted. CONCLUSIONS In 1993-1994, expenditure on surveillance of HIV and AIDS accounted for less than 1 per cent of the total allocation of resources to the National Health Service for all HIV and AIDS activities. Given these cost estimates, the number of infections which surveillance would have to contribute towards preventing in order to be considered cost-effective is low.