The Amsterdam Cohort Studies on HIV infection and AIDS.

The Amsterdam Cohort Studies (ACS) on HIV infection and AIDS are a collaborative effort between the Academic Medical Centre (departments of Retrovirology and Internal Medicine), the Central Laboratory of Netherlands Red Cross Blood Transfusion Service, and the Amsterdam Municipal Health Service. The aims of the ACS are to study the prevalence, incidence, and risk factors for HIV infection and AIDS, to study the natural history of HIV-1 infection, to carry out intervention studies, and to evaluate prevention programs. Many of the questions originally addressed by the ACS have now been answered, providing valuable insights into the prevalence, incidence, and risk of HIV infection. The emphasis of the study is now shifting toward the natural history of HIV-1 (HIV-2 being extremely rare). Several interventional studies have also been carried out, although this was not the original aim of the ACS.