Clinical evaluation of viral safety of coagulation factor VIII and IX concentrates.

Virucidal methods to inactivate infectious agents are based on various methods of heating or chemically treating plasma concentrates of coagulation factors VIII and IX used in the treatment of hemophilia A and B. This clinical evaluation of the viral safety of such 'treated' concentrates is mainly based on the prospective study of previously untreated hemophiliacs by means of clinical and serological markers of viral infection. Although there have been a few focal episodes of human immunodeficiency virus (HIV) transmission by clotting factors, these have been traced to ineffective virucidal methods that are no longer used or to clerical errors during the manufacturing process. Viral inactivation by pasteurization, vapor heating, heating in the lyophilized state at 80 degrees C and addition of solvent/detergent definitely decreases the risk of infection with hepatitis B and C. The current screening of plasma units for antibody to hepatitis C virus prior to inclusion in pools for concentrate production should further decrease the risk of hepatitis C infection. Other viruses, such as parvovirus and the hepatitis A virus, may still cause infections because they are quite resistant to virucidal methods. On the whole, virucidal methods have greatly reduced the risk of new HIV infections and, to a lesser degree, hepatitis.