[Effectiveness of recombinant DNA vaccines against hepatitis B in blood donors in an endemic region of South Brazil].

The objective of this work was to estimate the effectiveness of DNA recombinant anti-HBV vaccines in a retrospective cohort study of 1,012 Brazilian blood donors who completed the vaccination schedule (3 doses + booster of antibody titer < 10IU/L) during the period 1998-2002. The results showed that seroconversion rates were significantly lower among the donors whose antibody titers was measured six months after completing the vaccination scheme and among older donors, particularly those aged over 50. Overall vaccine effectiveness was 88.7%, ranging from 80.6% in the oldest (50 years or over) to 91.4% among the youngest (18-30 years) donors. The booster regimen was effective at reducing the percentage of non-responders. We conclude that vaccine effectiveness was significantly better in younger blood donors and that the anti-HBs testing interval influenced the vaccine effectiveness.