Background: To describe the trend in the number of HIV-infected persons and the number of AIDS cases in Spain between 1980 and 1998.
Subjects and methods: The following information was used: annual incidence of AIDS taken from the National Registry, AIDS deaths taken from the same registry and from the Registry of Vital Statistics, HIV seroprevalence in studies in sentinel populations, HIV incidence in cohorts of exposed persons, and reports of HIV infections in the registries existing in the autonomous communities. We considered three events of interest--HIV infection, AIDS and death--which were related using back-projection and compartmental models.
Results: HIV spread rapidly in Spain during the years 1980. Transmission subsequently declined by more than 50% to figures that probably do not exceed 6,000 new infections in 1998. The incidence of AIDS increased to more than 7,000 new cases in 1994 and has since declined to some 4,000 cases in 1998. The level of AIDS mortality has always been lower than the incidence; it increased up to 1995 and then dropped to less than half in subsequent years. The number of living persons infected with HIV, including AIDS cases, arose until the early years 1990 and has since remained steady at about 125,000 persons. The number of cases of living persons with AIDS has increased continuously, and is estimated at about 19,000 through the end of 1998.
Conclusions: The recent trend in new infections, AIDS cases and deaths is favourable, while the number of infected living persons remains very high.