HIV seroprevalence among blood donors in southern Brazil in the decade of 1990

The objective of this study was to establish the time trend in HIV seroprevalence among blood donors to a large blood bank in southern Brazil during the decade of 1990, and compare it to other data sources from the same region. To this end, a retrospective study of blood donor records in HEMOSC (Center of Hematology and Hemotherapy of Santa Catarina), federal state of Santa Catarina, Brazil, was conducted for the period 1991 through 1999. Annual seroprevalence of HIV among blood donors and its time trend for the entire period were calculated. The HIV seropositive fraction doubled every 3 years, reaching 4 new cases per 1,000 donors per year by the end of the decade, or roughly twice the national average. The increase occurred particularly among female blood donors, those over 46 years of age, and those residing in the Florianópolis metropolitan area. We conclude that, in the decade of 1990, the frequency of HIV in southern Brazil increased in the population seeking to donate blood. Possible reasons for this increase include an increased use of blood donation as a means to obtain HIV testing or increased transmission among low risk populations. The effect of increased transfusion risk of HIV transmission requires urgent attention.