[The effect of perennial partnerships on the prospective development in the AIDS epidemic]

Long-term predictions of the AIDS epidemic in the general population are possible only on the basis of an epidemiologic model which contains explicit assumptions about partner choice and duration of partnerships. Several models proposed heretofore predict too many AIDS cases in the next century, because they neglect the correlation between ages of partners. In heterosexuals it is frequent that many years pass between acquisition and transmission of HIV. Therefore, the correlation implies that most infection chains are disrupted because the age in the year of infection increases as new links are added to a chain. These considerations can be put into quantitative terms by adapting the classical concept of the basic reproductive rate to the special situation of HIV infection. In this way the impact of age preference and partnership duration on the spread of HIV is analyzed.