Specific inactivation of viruses which can potentially contaminate blood products

The viral safety of intramuscular immune globulin and albumin has long been recognized. Safety is the result of multiple barriers operating in concert, including donor selection, donor blood screening, immune neutralization, serendipitous inactivation and removal, and virus sterilization. Experience on the transmission of viruses, most notably hepatitis A and non-A, non-B (HBV and NANBHV) and human immunodeficiency virus (HIV), by coagulation factor concentrates prepared from large plasma pools highlights the difficulty of relying on donor selection and purification methods to eliminate virus transmission and the benefit of potent virucidal procedures. Before virus sterilization, the transmission rate of NANBHV and HIV by these concentrates approached 100%. Following virus sterilization, methods shown to inactivate less than or equal to 10(4) infectious doses (ID50) of hepatitis virus(es) greatly reduced HIV but not NANBHV transmission. Methods shown to inactivate greater than or equal to 10(5) ID50 of hepatitis viruses have eliminated HIV transmission and have greatly reduced hepatitis transmission. Elimination of transmission occurred before HIV and HCV screening and the development of purification methods shown to reduce virus presence. Based on an analysis of the initial virus load, the best coagulation factor concentrates available today are concluded to have a probability of safety equivalent to that of albumin. Introduction of sterilization methodology into the manufacture of all blood protein products should now be considered.