The Swiss Network of Dermatology Policlinics HIV prevalence study: rationale, characteristics and results (1990-1996).

The Swiss Network of Dermatology Policlinics (SNDP) has monitored the prevalence of HIV among patients treated for a sexually transmitted disease (STD) since January 1990. A questionnaire was sent to each policlinic in the network (Basel, Bern, Geneva, Lausanne, and two in Zurich) to collect information on their participation in this study and the characteristics of the network. The responses reveal that the six policlinics followed the HIV prevalence study protocol in a uniform manner and had similar logistical and organisational characteristics HIV prevalences in this population were high (1.6% among heterosexuals, 24.0% among male homo/bisexuals, and 35.7% among injecting drug users), have remained stable, and vary considerably by policlinic. In conclusion, we found that the policlinics have correctly implemented the HIV prevalence study and that the SNDP is a homogeneous sentinel surveillance system. Knowledge of the organisation and characteristics of the SNDP has allowed us to better interpret and present our data, and we recommend that other sentinel surveillance systems of this type collect this sort of information.