Risk of transfusion-transmitted viral infections

This study estimates the risk of transmitting human immunodeficiency virus (HIV), human T lymphotropic virus (HTLV), hepatitis C virus (HCV) and hepatitis B virus (HBV) from blood units using a seroconversion incidence model. Data from 13 blood transfusion centers collecting about 1 million donations per year and belonging to the Retrovirus and the Viral Hepatitis study groups were analyzed during the 3 year study period (1992-1994) for HIV, HTLV, and HBV and a 2 year study period for HCV (1993-1994). Seroconversion incidence rates were calculated and multiplied by estimates of the serological window period for each agent to obtain residual risk. The risk that an infectious donation was made during the window period was estimated to be 1 in 2 millions (95% CI: 1/10(7)-1/450 000) for HTLV, 1 in 588 000 (1/3 300 000-1/227 000) for HIV, 1 in 217 000 (1/714, 000-1/83 000) for HCV and 1 in 112 000 (1/333 000-1/43 500) for HBV. This risk was estimated for the totality of donations collected in France for HIV and HTLV. For HIV it was the same as above (1 in 588 000) and for HTLV it was much lower (1 in 7 millions).