To address the question of HAV prevalence and seroconversion in relation to clotting factor concentrates, we assayed an early serum for 339 hemophiliacs followed every 6 months by the Transfusion Safety Study in the period from mid-1985 until mid-1992. We found 58.4% positive around entry, with an age-specific prevalence that did not vary with age. In comparison to rates for anti-HIV-negative blood donors, they were significantly higher. Based on testing of subsequent sera, 11 hemophiliacs (7.8% of 141 susceptibles) changed their anti-HAV status from negative to positive. In 9 instances, positivity immediately followed the first dose of intravenous immune globulin. A possible seroconversion followed treatment with blood components, and a possible seroconversion followed intermediate-purity, solvent/detergent(SD)-treated factor VIII concentrate. Neither of these 2 patients was anti-HAV IgM positive, so that passively transferred antibody is possible. The high prevalence among hemophiliacs at entry must be further investigated by determining the expected background rate in a US population similar to the hemophilia patients, and by comparing anti-HAV prevalence associated with SD-treated and heat-inactivated concentrates.
ASJC Scopus subject areas