Epidemiology of viral infections in the Swedish blood-donor population.

The epidemiological situation regarding blood-borne infections in Sweden is favourable and under very good control. The prevalence of infectious markers in the blood-donor population is low. In 1993 the frequencies of confirmed positive tests were three in 1,000,000 for human immunodeficiency virus type-1 (HIV-1), one in 100,000 for hepatitis B virus (HBV) and three in 100,000 for hepatitis C virus (HCV). The safety of the blood supply is high and relies on strict donor selection, information on risky behaviour, and screening for syphilis, HBV and antibodies to hepatitis B core antigen, HCV, HIV-1, HIV-2 and human T-cell leukaemia virus type I and II (HTLV-I/-II). No donors with syphilis have been identified for many years. Screening for anti-HTLV-I/-II was introduced in February 1994 and no results have been reported yet. Donation is usually not permitted at the first visit, as the risk of transfusion-transmitted infections is greater in first-time donors. The risk of acquiring a transfusion-transmitted infection is low, but still a few cases of HBV and HCV infection occur each year among about 150,000 patients receiving transfusions. As far as we know, HIV infection has not been transmitted by blood components in Sweden since 1985.