[Epidemiology of HIV infections in Switzerland and the German Federal Republic--contribution of official surveillance systems, of anonymous testing and of blood donor screening].

Official records on HIV infections are useful instruments to register and demonstrate the spread of the virus in the population observed. The data resulting from the registries allow the estimation of the means and the variabilities of age, sex and the probable path of infection in the observed population. In Switzerland as well as in the Federal Republic of Germany, the mean age of persons whose positive HIV status is detected increases in the course of time. In Switzerland, relatively more women are infected, and injecting drug users play a more important role. In the Federal Republic of Germany the homo-/bisexual men seem still to be the most important group. Nevertheless, data without any reference baseline do not enable an inference to be drawn in respect of trends and prevalence in the general population. Data on blood donations, collected in Switzerland as well as in Germany, and data on anonymous testing collected in Switzerland, are helpful in estimating trends and prevalence in the general population. Data suggest that the overall prevalence is higher in Switzerland than in the Federal Republic of Germany. Of course, comparisons between different countries must take in account the different structure of reporting systems and attitudes toward these systems.