Abstract

The epidemiological reference scenario plays a central role in the present scenario analysis. The construction of economic and social scenarios will be accomplished using epidemiological outcomes. Modellers and epidemiologists defined and specified the contours of the reference scenario. Backcalculation has been chosen as the methodology to underpin the reference scenario. Assessments of the natural history (incubation time distribution) and pre-AIDS treatment were made. Country-specific surveillance data were gathered using a questionnaire that was sent to the national representatives of the European countries involved. These data on natural history, pre-AIDS treatment and country-specific surveillance parameters can now be incorporated in backcalculation. From discussions in the plenary meetings some basic themes for alternative scenarios became apparent. These themes refer to the effects of: pre-AIDS treatment ; the duration of incubation time; survival time after AIDS diagnosis ; prevention (expressed in number of HIV infections) and AIDS manifestation (related to neurological/psychiatirc morbidity). These themes need to cover the whole working area of the EU Concerted Action.