The risk of transmitting HCV, HBV or HIV by blood transfusion in Victoria

Objective: To report the incidence rate of hepatitis B virus (HBV), hepatitis C virus (HCV) and HIV in Victorian repeat blood donors and to derive the residual risk of transmission of the viruses by screened blood transfusion. Design: The interval from the previous whole blood donation was extracted retrospectively from Victorian Red Cross Blood Bank records for each of the 358 332 repeat donations given between March 1994 and December 1995. Records of repeat donors found positive for the viruses in this period were traced to the previous seronegative donation and accepted if screened by the same test. For each virus, the number of previous donations screened by the same test was calculated and the sum of all donation intervals used to derive the incidence of infection in the repeat donor population. Published intervals after infection (when a donation can be infective although seronegative) were used to calculate the risk of release of a seronegative unit which would be infective. Participants and setting: Homologous blood donors at the Red Cross Blood Bank of Victoria. Main outcome measures: Incidence rate of HBV, HCV and HIV in regular blood donors and risk of infective donations being seronegative. Results: The incidence of infection in repeat donors was: HBV: 1.67 per 100 000 person-years; HCV: 1.89 per 100 000 person-years; and HIV: 1.31 per 100 000 person-years. The risk of a seronegative repeat donation being infective was: HBV: 2.71 per million donations (adjusted to 6.45 to account for viraemias which remain seronegative); HCV: 4.27 per million donations; and HIV: 0.79 per million donations. Conclusion: The risk of transmitting HCV, HBV or HIV by repeat blood donors is low and compares favourably with overseas data. Repeat donors have an incidence rate of HIV and HBV comparable to that of the general population, but the incidence rate of HCV is lower for repeat donors than in the general population.