Monitoring the effects of AIDS prevention programmes is increasingly important but methodologically difficult. The use of surveillance derived measures of the occurrence of sexually transmitted diseases as indicators of high risk sexual behaviour, or of HIV incidence, has been widely recognized as a possible approach. This paper first examines the theoretical and empirical basis for this strategy, and highlights, using examples, some of the pitfalls in the interpretation of trends in sexually transmitted disease occurrence. Problems arising in the interpretation of the types of STD surveillance data currently available in countries in Western Europe are discussed. Ways in which STD surveillance systems might be developed so as to enhance their value in monitoring AIDS prevention are proposed. The paper goes on to identify areas of clinical and epidemiological research which might improve our ability to interpret such enhanced STD surveillance data.
